Outdoors, Green Living, Homesteading, Sustainable living, Green Building

Structural Building

Log Cabins


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First let me talk about the image above. This is the plan view image for what would be a square log home. It shows in brown square logs of rail road cross tie dimensions. We would use 7″x9″x10′ where the 9″ dimension is horizontal giving 9″ thick walls. I show where logs overlap on the ends in in lap joints on the sides. These joints can be constructed in numerous ways. Logs every other row will be offset 5′ or half the length of the logs so that joints are staggered. This means that on corners every other row will use a 5′ log. Also using a particular type of adz fake chinking groves can be cut out between the logs. Then by tacking in some metal lath or chicken wire and plastering fake chinking can be achieved. Chinking was originally used in American style log structures to fill in gaps between logs where logs were not tightly fitted. They either did this for economy of wood use or because of lack of skill needed to fit the logs tightly as they did in Europe.

This next set of images is of the above design. This is a concept drawing.
No or incomplete engineering has been done.

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I don’t show door or window locations. Also inner walls could be added to divide the spaces into rooms and hallways. You can also imagine where porches might be, in fact they could be all the way around. Below lower floor level will be a rock or block stem wall up at least 1.5 feet if not higher. The stem wall could be wide so that the floor joist rest on it as well as the log walls.

The nice thing about the Dog Trot design is that it can be constructed one module at a time as the owner and usually owner builder has time, money, materials and manpower. You may also live in the completed sections while you expand and add on. Even the 2nd story could be built later, though the roof structure would have to be removed and then added on top.

One module from stem wall up 8′ high would require 168 cross ties, that is 12 every 7″ of height. If you could get these at $25 each, a bare min price under today’s economy, we would be talking about $4200 per each lower module. If you could make these yourself with a mill cost might drop to $4 per cross tie or $672 per lower module. Could possibly get that cost down even more. If you milled this yourself from a trees you might need trees that are 12″ to 14″ in diameter. You might get 3 logs per tree. If it works out this way you would need 50 to 60 trees for on module. And remember in trying to get logs of this exact dimension you will also end up with some lumber to use. So you can see the possibilities of this design for yourself.

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As a prerequisite you may want to read my Timber Frame, Post and Beam, Beam and Stringer article.
Log cabins come in a few types.

  • Type of Logs
    • Round Logs
    • Square Logs
    • Whole Logs
    • Half Logs
    • Partially Round Logs
  • Orientation of Logs
    • Horizontal Log Walls
    • Vertical Log Walls
    • Single Log Walls
    • Double Log Walls
  • Fit (how tightly they go together)
    • Chinked
    • Well Fitted

I have a lot to write here, so keep check on this article over time. I decided to go ahead and publish this article in a somewhat incomplete state. I have more written about logging currently than anything else. But at least it will give you some ideas.

Log cabin building is a fairly huge topic and I have no intention of being comprehensive here. I also have no intention of competing with the many great books available on this topic. I will simply note some interesting things that I have learned in my studies and from conversations thus far.I will not be covering foundation, stem wall or chimney of rock,  concrete or masonry in this article. I may talk about chimneys made from small logs spaced apart well and infilled with mud or cob. The log cabin books and other books cover these subjects well. I will write about these topics in other post later.

Log walls are strong, meaning they can bear a lot of weight for roof structures. They can bear something around 100,000 lbs per linear foot, depending on width and type of wood.  This means that little engineering is needed for log structures. If you keep things simple no engineering would be needed for the roof structure. Log walls are energy efficient and can have R values from 20R to 35R or even higher if it were a double wall.  Soft woods tend to have higher R value than Hard woods.  As an example your typical 2×4 wall is R11 and 2×6 wall is R17.

I talk about what I have read and heard in regards to logging in this article. It has been recommended that if you do not do logging as a profession then you most likely will want to hire this done. Logging is dangerous work. Machinery is dangerous to operate.   One idea I was given for getting logs is to buy a wooded lot and go halves with a logger to log them for you. Keep the lot for an investment and campsite or a place to keep some goats. In the USA in many areas large logs are difficult to come by. Most areas have nearly all pulp wood for timber, especially in the south east. And in fact wood is being grown now for the growing array of composite construction materials. This means for glue-lam beams and post, oriented strand board and particle board.  So logs may have to be imported from out of state for many log homes.  Many are imported from western USA. Logs need to be seasoned before construction for a year or more. This is where they dry and shrink.

Of the types of logs I personally like square hewn logs the best. For one thing much of the sap wood that would rot is sawn or cut off in order to make the log square. I like the looks of the chinking so I’d probably cut a chinking groove between two logs fitted tightly and make up fake chinking. After boards have been removed from the outside of larger logs often the heart wood is left which if left at the dimension of 7×9 make great cross ties. At the time of this writing a 10 foot 7×9 hard oak cross tie might cost $25 to $40. It would require about 240 of these to make a 20’x50′ or 900 ft2, single story cabin. So at $25 each we are talking about $6000 for the cross ties, and that doesn’t include delivery charges.

  • Round (Lincoln log style)
  • Square end
  • Diamond end
  • Doves tail end

Logging and Milling operations.

Logging

First let me say that logging is very very dangerous. One must learn to correctly determine direction of the tree fall, and even then there is a chance that it may veer off course from planned direction of fall. Wind, splitting and rot,  leaning or off balance, improper final cut and lodging in nearby trees can all change the direction of fall. A tree can split and kick backwards towards the feller. And let us not forget about the falling limbs called “widow makers”. A tree that one tree falls against can snap back and throw a limb like a sling shot towards men and equipment. Below I will list some safety equipment that should be worn.

  • Hard hat
  • Goggles or face shield.
  • Leather gloves
  • Leather Chaps
  • Steel toed leather boots.

Logging equipment can be very dangerous be it tractor or skider, truck trailer, chainsaws, axes, hand saws. Saws and axes should be placed in the open laying flat on the ground and not leaned against trees and equipment. Chain saws should be placed on and against  a sturdy surface when started, not simply held in the air. Chain saw should be off when checking or adjusting chain tension. Beware of hot mufflers and parts that could cause burns. Logging chains can break and fly towards people and equipment at high speeds with great force. Respect equipment and ease into learning the use of them.  Learn to gauge your comfort level and don’t hurry. Learn to get a feel for the handling and operation as you would in most other kinds of work. Don’t be overconfident or careless.

Notching and Back Cut and Felling

A notch should be cut in the side of the tree at the desired direction of fall.  This notch is horizontal at the bottom and about 1/4 to 1/3 the diameter of the tree in depth. Then at a 45 degree angle from back of notch upward to outside of tree bark. Large trees may need one small notch first then larger notch made from the first small one. Or on very large trees two small notches, one on top of the other, then the large one from those two further in. With an axe on larger trees it may be necessary to chop on one side then the opposite then middle to get chips to fall off then rinse repeat. It is possible for two fellers to chop at the same notch at the same time to speed up the notching. If your saw bar is not long enough to go all the way through the tree, then cut one side first on the back cut until the remaining uncut section is shorter than your bar length. For leaning tree’s that are leaning in the direction of fall, cutting on both sides of back cut first will lesson splitting and kickback.

Back Cut

The back cut should be horizontal and made about  two inches above the base of the notch and towards the notch and direction of fall. You can place the double bit axe in the notch and use its handle as a pointer to give you the direction of fall. The back cut should be made to withing a couple of inches of the notch and should be above and over the back of the notch by an inch or two. The wood left in-between the notch and back cut forms a hinge during the fall of the tree. As the tree begins to fall yell the famous word “Timber!”.  This is  a warning to others in the area to watch the tree as it falls and be ready to move fast if needed.  The back cut hinge can be left thicker or thinner on one side or the other to guide the direction of fall at the last moments. If two people are using a cross cut saw to make the back cut one should keep the other informed about how close he is to the notch.

Other difficulties might be pinching of saw on the back cut in which case you would use a sledge and wedges to pry the tree off the saw. Wedges may also be needed for leaning or off balance trees. If splitting is anticipated wrap the tree with a log chain and use wedges to tighten the chain around the tree.  The final portion of the back cut may have to be timed with the wind. If the wind is in the direction of the fall then wind can be used to push the tree on over. If its against the direction of fall then try to finish the cut as the wind slows or dies down. If the wind is to one side or the other then it can push the tree out of the direction of fall a bit. Time the back cut and the thickness of the hinge on each side appropriately. If the wind is too erratic or strong felling operations might not be advisable at all.

Trees should not be felled down slope, only up hill, or up hill to one side or the other a bit. Trees that are felled down slope tend to break or shatter. The feller should move slightly uphill and to one side or the other as the tree falls.  A tree may kick backwards down hill and strike the feller who is down slope from it. Try not to fell a tree on rocks or across other felled trees which would cause shattering and splitting. If a tree lodges in another tree then use a tractor and chain  to pull it off the stump at the base. Never cut the tree that it is lodged in and don’t try to stand on it and shake it to get it to fall. A stump should be no more than one foot higher than the ground on the uphill side. Sometimes because of rocks this is impossible though.

Limbing

Standing on the tree trunk cut limbs off is tricky dangerous business. Inexperienced limbers should avoid this until they are confident after seeing the reaction of trees as limbs have been removed. Trees tend to roll a bit during limbing.  Sometimes on large limbs notches may need to be cut out similar to the notching for felling except that its more of a 90 degree notch. Then a saw may be used to finish the cut horizontally.

Bucking

This is where you cut sections (logs) of the tree out for lumber making. The person who decides where the tree is to be cut should probably have some milling experience and also know about how rot and other defects affect milling operations. A tree should be bucked such to get the most use from the logs/boards (board feet).  There are many defects which can affect bucking and calculating board feet. A few would be rot, punky sapwood, splits, fire damage, large limbs, knots, bends, forks etc.

Calculating Board Feet

Board feet can be calculated with what is called the Scribner C Log Rule. This table is imprinted on a ruler that is carried by the person who calculates board feet. It has diameter across the top (6″ increments) and length down the side of the table (1 foot increments). Table values are in (tens ‘meaning times 10′) of board feet.  There are quit a few guidelines for how one deducts for various defects from the total board footage of a perfect cylinder. Tree’s that vary much in thickness may need more than one board footage calculation for a single log.

Beware that trees can have gravel, rocks and metal as in spikes and nails and staples in them. Metal and saw teeth can become shrapnel. Also note that there are some people around who resharpen band saw blades.

Chain saws and associated equipment.

I hear that the two main best brands for chain saws are Husquvarna and Stihl. Stihl has been recommended to have the best performance however parts are harder to come by than for Husquvarna.

  • Gasoline powered Chain saw (saw, bar and chain)
  • Chain saw oil to be mixed with gasoline.
  • Chain saw bar oil.
  • Chain saw grease gun (for greasing the bar sprocket)
  • Rip Chain
  • Wrench for taking chain saw brake apart to get chain off.
  • Screw driver(small philips) for adjusting chain tension and idle speed
  • Sharpening File (round file) and Handle
  • Angle guide for hand file
  • Electric Dremel tool or drill motor with sharpening stone and angle guide.
  • Air powered sharpening tool for trucks with air systems.
  • (Air powered chain saws have been used in the past)
  • Air hose for air powered chain saw.

Other felling equipment.

  • Double bit axe
  • Broad axe.
  • Heavy axe.
  • Axe.
  • Logging Chains.
  • Wedges
  • Cross cut saw (one and two man)
  • Bow saw (for limbing)

Logging operation tools and equipment.

  • Near 25 horse power tractor.
  • Team of mules, horses, donkeys or oxen.
  • Truck or Van that can pull 3 to 4 tons.
  • Twin axle flat bed trailer that can haul the tractor or a few logs or lumber.
  • Log arch for moving single logs.
  • Power winches.
  • Come-a-longs.
  • Logging Chains of various sizes.
  • Wedges of varying sizes.
  • Sledge hammers of varying sizes.
  • Boards to use as ramps for pulling logs onto trailer from side.
  • Log dogs (A rod with spikes on each end)

Milling equipment

  • Circular saw mill powered by pickup truck rear drive wheel, truck set up on blocks.
  • Small Band saw mill.
  • Granberg Chain saw mill attachment (Alaskan Small Log Mill).
  • Beam Machine chain saw guide.
  • Electric Plainer
  • Table Saw
  • Two man rip  saw (for saw pit).
  • Hand Plains
  • Adzes

Wood Roofing Equipment and materials

  • Mallot and Froe (for splitting shakes ‘wooden shingles’)
  • Riving Horse
  • Shaving horse
  • Draw knife
  • Nails
  • Weight Poles and struts (for weighting wood shakes down until they dry)

Standing seam metal roofing equipment

Beam working equipment

  • Adzes
  • Draw Knife
  • Slick
  • T-Auger
  • Chisels
  • Mallot
  • Boring Machine

List of corner notch types

  • Half Dovetail
  • Compound angle Dovetail
  • Full Dovetail
  • Keyed Dovetail
  • Half Notch
  • Diamond Notch
  • Square Notch

This next set of photo’s shows the operation of the Grandberg Alaskan Saw mill. I am using my Husquvarna 55 with 18″ bar. It took about 30 minutes to saw off that first side. I was resting me and the saw a lot. It really moves along a lot faster than that. I bought two 10 foot 2×4’s for the straight edge. Using some scrap I tied the 2×4’s together on bottom and nailed the scrap to the log, with the 2×4’s on top of the scrap.  One thing to remember is that you don’t want your chain saw hitting the nails, so make sure its moving along deeper into the log than the nails penetrate.

If you do not get the first side perfectly flat for some reason you may place on top of it a couple of strips of angle iron nailed down to be a straight edge. As a matter of fact it would be good to make an angle iron guide or square tube steel guide similar to the 2×4 version I have below.

I realized after I started that I had to move the 2×4’s out so that they overhung the log to get started. In reality I should have bought 2×12’s to mill 10′ logs. It should hang over a foot or so on each end. I intended to cut 10′ boards from this old dried elm stump.  However 9 feet or so is all the practical length I can get from this log. Next I intend to cut of at least one side or maybe both with a tool called the Beam Machine and my chain saw. Then I will cut 2″  to 3″ planks from this log to use as garden box boards.

I demonstrate the use of the Beam Machine which uses a single 2×4 as a guide to cut off the side of a log. I realized after I started that I should have been 1″ further in. It looks to me like lumber could be made using this Beam Machine. If you didn’t want to use the lumber made this way for your home then it could always be used for barns, chicken coops and dog houses. The beam machine needs a flat surface made with the Alaskan Saw mill on larger logs or on 6″ to 8″ dia logs you would simply nail the 2×4 down the top of the log. You could then saw off each side without moving the 2×4. Rotate 90 degrees and do it again and you would have a beam of 5″ to 7″ in size. On a larger log you might first use the Alaskan saw mill to flatten to sides then use the beam machine to cut multiple beams from one log.

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Recommended Books
The Classic Hewn Log Home2005Charles McRavenStory Publishing
Old ways of working wood

Simple Small DIY Metal Buildings and Kit Buildings


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The above design when worked up in 3D resembled a Mayan Temple. Anyway I’ll state again that this is a design concept drawing with no engineering.

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You may also be interested in reading Metal work shop tool wish list.

There are quit a few companies producing kits for metal frame buildings now. I’ll find some links and post a few. I’ll list a few types below.

In this article I will mostly talk about some ideas that I have for small simple metal buildings made from scrap angle iron or metals. I feel that I could construct a frame from scrap for something to cover less than 400 square feet(37m2) of floor space without needing an engineer or architect if I do some research first and think through my design carefully. I would also not span distances of more than 16 feet (5m). With the kind and sizes of scrap most of us have available in today’s world, buildings of this size should be safe enough. Though you might consider occupancy in your safety considerations. For example A shop is occupied part of the time. A storage shelter rarely. A home or living space possibly daily. The more serious the occupancy application, then the more rigorous thought that goes into the engineering requirements. As another example if snow and ice buildup might be a concern then don’t occupy your building when snow and ice is on it. If wind was a concern then don’t expect to have to occupy it during wind storms and hurricanes. Nothing replaces the added confidence in money spent on structural engineering however. Though even engineers in their calculations consider occupancy and beef up the engineering based on seriousness of occupancy. You just have to be careful enough with the “beefing” or you will create a structure that can’t hold itself up.

If I can find some info about the relative strength of some I-Beam or simple truss designs that will span 16 feet (5m) or less I’ll post them here. As far as roof weight goes, we are talking about mostly snow weight possibly combined with wind.  Though a flat sod covered roof needs to support 200 lbs per square foot (90kg) or (1000kg per m2) which doesn’t count the weight of the structure itself.  A steep roof with slick roofing material which might be heated part of the time would not be as worrisome as a lesser sloped roof with rough roofing and no heat.  The dome’s and half rounds would be less worrisome in my opinion because they would hold up less snow or ice. Round shapes seem to be much better at handling wind as well. The A-Frame would be less worrisome because of its steep roof (for ice or snow) though it kind of sets up like a leaning sail for the wind from 2 directions. For wind a 45 degree sloped (12:12 pitch) A-Frame might be best.

None the less pay close attention to other metal buildings in your area where you may inspect the framework. Note the types of metal, shapes of members and thicknesses of members.  In some cases you might want to overkill on bracing and with support poles or tie beams to make up for lack of engineering. Though note that extra weight in roof structure could be a problem. One advantage of metal frames is that they eliminate the need for support poles in spans where wood requires it.  400 ft2 of floor space in rectangular would be 20’x20′(6mx6m) or 10’x40′(3mx12m). 400 ft2 in round would be 22′(3.2m) in diameter and about 75′ (22m) in circumference.  If you have any doubts search out a structural engineer.  Also the businesses that produce metal buildings might work up some plans for you cheaply. They have engineers on the payroll and use software specially designed for metal building architecture. On a side note, when commercial poultry producers first began using metal frames which would span 40 (12m) to 50 (15m) feet without poles, some collapsed due to snow weight the first few winters in the southern USA area.  Even engineers make mistakes. In this case I’m sure it was due to pressure to save on construction cost because of building competition.

I have no intention of making up the square framed metal buildings from scrap metal. If I did it would only be very small structures and probably only for storage, animal shelters, or rain sheds. I will post some links to some sites that design and sell kits after I get time to look some up. Forgive me for the crude sketching, I’m sure it leaves a lot to be desired. My sketching is better than nothing though and at least it gives the reader a hint as to what I’m talking about in this article.

A-frame, vs more conventional box designs, has a much steeper roof and will not hold snow or ice or will shed the snow or ice more quickly, especially if the roofing material is slick and possibly heated from underneath. Lean-to is another example for an easy design for DIY.  A Lean-to where the roofing is steep and comes to the ground or nearly to the ground is somewhat like a half a-frame. On a side note a pyramid shape would be like crossing an A-Frame with a Hip Roof design. I have seen some large pyramid shaped metal buildings around the country in industry. I was unable to determine what they were used for exactly though.


There might be two ways to make a set of half circle ribs for this type. One would be pipe bent with a pipe bending machine to the perfect curve for the size of building being made. Angle iron could then be used as stringers going between the half pipe-hoops.  This is similar to the pvc poly tunnel construction for quick and dirty green houses for gardening plants. Corrugated metal roofing would be perfect for this where the rows of the corrugations would be parallel to the length of the structure. This metal roofing would bend easily over the structure and frame.  Caulking and proper overlapping would be required. Screws with washers and rubber seal washers would be used to fasten the roofing to the frame.

The second type of frame would use a half perfect polygon shape where a number of angled bends would be made in a piece of angle iron.  At each angle one side would be cut downward to meet the 90 degree bend so that you would only be bending one side which is flat. Then there would be a small amount of overlap at the bend on the side that was cut where it could be welded together. Again angle iron would be used as stringers.  Same roofing method as the first. And actually angles could bent in pipe at given distances for the same effect by using hand operated pipe bending equipment.

Lets say that you want to figure the angles and distance between angles for the bends.  Simply divided 360 by the number of angles in the circle (even number so that one angle ends up at the very top).  Draw on a piece of graph paper a Circle representing the full or half circle shape of the half hoop (rib). Next draw a line from the center of the circle 90 degrees to the top of the rib. Then draw and array of lines all the way down on both sides along the circle from the center using the calculated angle from above between each line. Next draw lines from bend point(where each line touches the circle) to bend point around the circle inside it.  You may now measure the distance between angles and angles of the bends themselves.  I will try to post some diagrams for these two types soon. One other idea is to take a grain or feed bin and cut it in half, viola,  instant roofing. And what about giant corrugated culverts?

Below is a calculator that would help you in the design of a frame for a half round, vertical axis dome, horizontal axis dome frame. Click the image below to bring up the calculator. You will enter the number of bends in the frame. You will also enter the radius of the frame in “units” not feet or meters, so that it can represent feet or meters. This is the number for a full circle. So half that number or less would be for the top half of your typical half round or dome structure.  The yellow line indicates the number of angles and sides above ground level. It shows half the distance of the perfect  polygon which will be the total length of all the members of the rib.  It also gives the length of the rib pieces between angles and the angle between rib pieces. As you can see, the more angles or sides you have the rounder the structure will become. However more round means more work involved in constructing each rib. This could be used for metal, plastic or wood frames, or any combination of materials. However do not use this for engineering but only for design purposes. If you have any doubts seek out a qualified structural engineer.

The “clickable” calculator (Polygon Calculator) above can also help you to determine the angles and lengths  for metal pieces needed in a cone shaped roof such as the Silo/Yurt type roof below. These metal pieces might be overlapped or be put together as a standing seam roof. For the calculations though use the distance from the edge of the roof to the peak for the radius, not the actual horizontal distance.  For example the radius above was 8, but if you used right triangle math to figure a hypotenuse for a rise of five feet then you would need to resupply the radius as the sloped distance of around 10 or 12 feet.  This would give you proper angles between pieces and lengths at the bottom of the slope.  Anyway it you use your imagination a bit, this calculator will work out for you for this purpose as well.


Feed bins, Grain Silo’s and the Mongolian Yurt Shape are all basically the same.  You have a vertical wall shaped like a cylinder standing up, with a cone shaped roof.  I will be looking up some manufacturers for feed bins and grain silo’s to post here. For the home made version why not use the design from the Yurt. Flat or angle iron could be used for the sides. But at least one of the directions of the roof lattice would need to be angle iron for strength if not both.  Built to the wooden yurt specks I’d say this will be far more than strong enough to hold up a bit of ice and snow.  I’m not saying use solid steel that is 1×2 (2.5cm x 5cm) or 1×3 (2.5cm x 7.5cm) but tubular, U shape or angle iron with those dimensions. Wind would be no problem with a frame like this. Guy wires would probably not be needed as they are for the wooden frame yurt.  On a metal frame like this square doors could be designed into it instead of coffin shaped doors. I would roof this with flat tin or sheet metal with standing seams. I actually found a chapter in a book on standing seam roofs that was pretty good. The book however was about square log homes called “The Hewn Log House”.  Each piece of the yurt standing seam roof would be like a piece of pie, where two pie pieces come together there is a standing seam. It could be bolted or screwed down at the top around the compression ring area.  Again if you were really concerned about roof support, a ladder could be made in the middle that would run to the sky light at the top and would brace the roof with pole like support. Corrugated sheet metal could be used for the sides and as I said earlier it will bend nicely around the curved shape. In this case the rows of corrugations will be vertical.



Geodesic domes are a very strong structure made of triangles inside hexagons or pentagons. Search the web for geodesic dome frame calculators or use the one at Desert Domes They show exactly how to position the pieces and their lengths and angles.  Angle iron, a welder and cutting torch will work nicely here.  Keeping the thing shaped like a sphere is simple. Use stake in the center with a cord or rope attached and the rope should have a knot or stick tied at the distance of the radius of the structure.  Just pull this taunt at each joint to make sure its in the right position before welding. If needed a torch can heat and bend something to the right position. A friend of mine at Minimal Intentions has some blog post about a metal geodesic dome frame he made from electrical conduit. He spent $300 for the conduit, cut and flattened ends, drilled holes and bolted the thing together. It spans 19′ (2.9m) and has around 350ft2 (33m2) of floor space. As a testament to its strength he sleeps on a trampoline that has been suspended about 8 feet above floor level with steel cables.

Roofing is another problem altogether and I personally don’t like asphalt shingles for geodesic.   I’d suggest some kind of flat metal roofing but not corrugated unless it were very finely corrugated.  If its flat sheet metal roofing I might consider welding, soldering or braising  it to the frame, though this might be expensive, it would be long lasting.  Caulking, screws, metal and rubber washers to fasten the roofing down. Roofing would probably be cut in triangular or hexagonal shapes. Could be cut in double triangular shapes as well.  If you used Plexi Glass or glass for roofing then you would have an agri (agricultural or green house) dome. Sky lighting would be easy by using plexiglass for roofing a few of the triangles here and there. Pipe could be used instead angle iron and so could rebar.  There are probably many variations on this theme. The dome forms a half sphere and it wouldn’t have to be set right on the ground. I could be set up on a partial or full circular wall or poles or whatever to get it up a bit higher for more head room.





There are two types of domes I found that are dissimilar to geodesic. Horizontal axis ribs and Vertical Axis Ribs. To imagine the horizontal axis ribs think of the old horse buggy with the folding cover or the convertible car and its folding cover. Note the ribs on these covers. For the vertical axis ribs think of the wire whips for whipping eggs and cream and potatoes that cooks use or maybe the umbrella. Though I have seen some whips that cooks use which are more like the Horizontal axis ribs.  Another great example for the horizontal is that famous set of buildings in Sydney Australia that we see on movies a lot, and I can’t even tell you the name of the building. At any rate what I said above for the design and construction of the half round ribs will work for these two types of domes as well.

Sea Vans or Ocean containers are probably one of the easiest solutions to quick and dirty DIY housing that is rugged, durable, long lasting, and water tight. At the time of this writing I could get a 53 foot sea container brand new for $5000 to $8000. And they even come with nice looking wood floors in them!  This would be one of the easiest methods for a non skilled builder to use in my opinion.  And there are many many ways containers can be combined. They can be buried for underground housing, though probably not best to do this below grade or too deep.  They can be bermed and earth roofed easily. You can weld metal structure to them or bolt it to them easily. I hear the corner areas are the strongest points for stacking these. Roofs can bow and sides are not necessarily strong even though they are corrugated. However stacked or just setting in the open would cause no alarm.

I show using the image at the top of the article an idea that I really badly want to try some day where I would take two 53 foot (15m) containers and put them side by side but spaced 16 feet (5m) apart.  I would span them every 1.5 (.5m) feet with a beam of some kind to hold up an earth roof (which might require post support to be added to the end of each beam because of the earth roof weight, the containers themselves might not support the earth roof weight).


To support an earth roof of 300 ppsf there are two methods I recently heard about on a podcast. On is totally with wood on the inside. You use 4×4 pine post(studs). Place them every 4 feet just above a floor runner. Floor runners are on 12 inch centers in the floor of the ocean container for floor support. On top of the 4×4 use two 2×8 or 2×10 all the way down so that you have 4×8 or 4×10 on top of the 4×4 post. This comes to within 6″ of the metal ceiling. Then across you use 2×6 on 16″ centers placed on top of the 4″ ledge formed by the 4×8 or 4×10 bearing plate. This is adequate for holding up 300 ppsf which would be 4″ of Styrofoam insulation and 1 foot of earth and 6 feet of snow and water in the soil.

The next method requires welding. You get U shaped studs and weld them in every 4 feet. You then use a 2″x3″ piece of angle iron on each side. With 3″ horizontal for resting 2×6 boards on. Weld that in on each side. Next place your 2×6’s again on 16″ centers. Also your 2×6’s might need to be camphorred a bit with some trimming. This means making a slight arch shape to match the roofs slight arch shape for a tight fit.

Double pane non operable windows would go between each beam, with maybe an operable window here and there for ventilation. I would berm up to within 6 inches of the top of each container on the outside of this structure. I would sod roof the containers and the center roof with 6″ of earth and sod. I might extend the berm around the ends of the containers on all 4 ends (2 ends on each container)  I’d cut a door in the middle of each container on the inside. Some kind of flooring on the inside and some type of end walls, with double doors on  each end. A stove or fireplace for heat. I would cut some holes in the tops of the containers on the sides all the way around for very small windows for sun lighting. If you build up a pad a couple of feet for the containers to rest on then the floor in the central section could be 2 foot (2/3m) lower and give 2 more foot of head room. This would give 12 feet (3m) of head space in the center with 7.5 feet (1.5m) in the containers. This design would give 1500 square feet (140m2) of space in the structure.

As for the roof structure in the middle, if it were only a frame for holding up a metal roof that might not need too much support enhancements on the containers. If it were earth then you would need to support it with columns and bearing plate as we talked about on the inside. The corners of the containers take a lot of weight. But the sides need reinforcement.

Variants on this might be larger spans in the center (more well engineered) and containers on the sides double stacked for 2nd story rooms giving 20 foot(6m) of head room in the center. The 2nd story containers would not be bermed but would be well insulated. They would still have the sod roof on top and the sky light windows between beams all the way down.

There are many many many variation on how containers could be used for structures because they are made to be so strong for the rough trucking and ocean shipping business.  You are only limited by the imagination. And they can be strength enhanced.

Other roofing for metal structures ideas could be in the use of papercrete, gunite, shotcrete and plasters. Plasters could be made lighter with the use of something like vermiculite instead of sand in the mix. And I’m sure there are many other options once one gets to looking into it. Certainly canvas for the half cylinders would be a snap, since its a mere rectangle. Plastics as well.

There could be a huge list of tools that would go well with this article. But I will only mention a few below.

  • Sheet Metal Brake (not necessary and might not be cheap)
  • Metal Brake (not necessary and might not be cheap and may require 3 phase electricity)
  • Oxy- acetylene Cutting Torch and Welding Torch.
  • Arc Welder
  • Other types of welders, cutters.
  • Drills and metal bits
  • Wrenches, Sockets, Ratchets
  • Scaffolding
  • Pipe Bending tools

List of tools for working standing seam metal roofing.

  • Duckbill vice grips
  • Seaming Iron
  • Wooden Mallet
  • Roofing Tongs

Below is a table of metal strengths. These are approximated so use them for thinking about design but not for actual engineering. For actual engineering you would use numbers for the specific exact metal type and situation from the Machinery’s Handbook, in the Strengths of materials section. Yield Strength is basically bending to the point of plastic deformation. Whereas Elasticity is bending to a point where it can snap back into original shape. This can also be known as deflection or springiness.  The values are PSI (Pounds per square Inch)

Strengths of Metals
Type Tension Compression Shear Yield Elasticity
Tension
Elasticity
Shear
Cast Iron 20,000 to
60,000
80,000 to
240,000
30,000 to
60,000
None 12,000,000 to
18,000,000
5,000,000 to
8,000,000
Carbon Steel 60,000 to216,000 60,000 to216,000  45,000 to160,000  40,000 to150,000  30,000,000  11,500,000
Steel Alloys 80,000 to285,000 80,000 to285,000 60,000 to214,000 25,000 to228,000  30,000,000  11,500,000
Stainless steel 70,000 to230,000 70,000 to230,000  None 30,000 to195,000 28,000,000 to29,000,000 13,000,000 to14,000,000
 Aluminum Alloys 10,000 to110,000 10,000 to110,000 7,000 to48,000 8,000 to23,000 10,000 to18,000  None

How might you use these values above? I mean we all knew that metal is hard and strong. I’m not an engineer so this will be a discussion from an apprentice or students point of view. We have to learn about these forces and how they act on the materials. We also have to be able to imagine simple situations within more complex situations. I talk more about engineering in the article Timber Frame, Post and Beam, Beam and Stringer and you may want to read this as a perquisite for this article. For this DIY metal building stuff I’d say as anyone else would as well, KISS principle , Keep It Simple Stupid.

Lets say you want to roof an area between two ocean containers as in my above idea and example.  Lets also assume that the containers are strong enough to support the weight for example purposes. Lets use 20′ containers and shorten the distance between them to 10′. In a flat system you call the beams that span between the containers rafters or joist. On top of the rafters would be stringers running perpendicular. This forms a grid skeletal framework which would support roofing material and anything that ends up on top of the roofing material, such as snow, ice, debris etc.  We would calculated first weight on a tributary areas. If our rafters were spaced out at 2 feet and 2 feet between stringers, a tributary area might be 2’x2′. So there would be 50 of these areas combined in the total roof space. You could figure weight on each stringer and then each rafter in the 2×2 area. Then total for the roof. Half of that weight will be on one container, and half on the other. You could then figure weight per linear foot along the top of each container.

Typically you would use angle iron, tube iron, I beams and possibly flat iron strips for the stringers. Lets keep it even simpler than that and use solid square rods for both stringers and rafters. Though you could probably find 1″ tube steel with strength properties of our example here which is using solid rods. Span is important when considering bending. When a member is being bent, say from above, you develop compression forces on top of the member and tension forces underneath it. Lets say you push down with 200 pounds force on our beam that is spanning 10 feet. This will generate a certain amount of compression and tension based on the span of 10 feet. If we stretch that span out to 20 feet then you can see that even with the same weight the compression and tension forces increase greatly. Whether or not this increase is double or far more than double I don’t know yet.  If these stresses reach the PSI limits above for the given metal type, then permanent bending or (yielding or plastic deformation) occurs. If not then springy type bending called deflection can occur.

From the table above you can see that we can have up to 45,000 psi in shear weight for carbon steel before the rafters will break/shear. In our roof example so far we might have 200lbs per ft2 (far greater than a normal roof, this might be a weight for a sod earth roof with 5 feet of snow on top) which translates to 400lbs per linear foot on the stringers. or 800lbs on the point of contact between the stringer and the rafter. Since in our simple example our stringers and rafters are 1″x1″ this means the roof weight alone is only 800 psi on the rafter. This is well below the shear strength of the rafter member. Added to this 800PSI will also be the weight of the stringer member 2 feet long. The Machinery’s Handbook can tell you this weight in its sections on weights of materials. For arguments sake lets guess that the steel 1×1 member weights 3.5lbs per linear foot more or less. This brings the psi up to 807psi.

We can not span any length we want with our 1×1 rafters. If we keep increasing the length of the span eventually it will sag and even collapse. We need to know based on 10 foot span what kind of weight it will support without bending. We have 807lbs every 2 feet plus the weight of the rafter which is 3.5lbs per linear foot. Dividing the 807/2 gives 403.5lbs per linear foot plus 3.5 lbs or 407 lbs per linear foot. And 4,070 pounds per rafter. 10 rafters gives us 40,700 lbs for the entire roof. Which is 20,350 lbs on each sea container. We could distribute this weight down the length of the container to be 2,035 lbs per linear foot. Translate this to psi on the rafter to container and we get 4,070 psi. That won’t shear the rafter.

Engineers Edge Web site Has some formula’s we may use. The bending formula says bending stress = (3 x load x length)/(2 x width x (thickness x thickness)). I wish I understood how they came by this formula but I don’t. Our load will be 407 lbs. Our length is 10 feet or 120 inches. (3x407x120)/(2x1x(1×1)) or 73,260. Looking at the carbon steel chart above lower end strengths are 60,000 for tensile and compression. If we are correct here that means our roof might be too heavy. If we shorten the span to 8 feet then we get 58,608 from the formula. This seems acceptable. There are many ways to change this so that it would work out.  There are many ways we could change the situation to make it work out.  We could add intermediate support post and/or bracing. The member sizes will need to be increased to larger than 1×1. We could space the rafters closer together such as 1.5 feet instead of 2 feet. Also if we were not doing a sod roof then we could reduce the roof load to normal roof loads. We could also change the metal type to something that is both known and stronger. There are carbon steels that are stronger than the weakest ratings in the above table.

A person could certainly make up a spreadsheet to calculate these figures for them quit easily. Then to design a different sized roof system all that is needed is to alter a few key values. For a free spreadsheet Google for “Open Office” and I think their spreadsheet is called “Calc”.

I didn’t talk about fastening anything. If we welded the grid frame it would add a lot of strength. It would also add to cost and time. But remember a good weld is stronger than the metals being welded. I have no info to give you on bolting, though you could make brackets to go around the 1″ steel bars.

There are 3  to 4 methods for engineering anything that I have found so far. One is by using math and calculations. The other is by using tables for values and codes for guidelines and is called Prescribed method. These tables have been calculated based on materials testing and engineering formulas.  Then there is the empirical method.  Empirical is like wind tunnel testing. Finally if you count it the 4th method is in cloning (copying, borrowing or reverse engineering which is also a form of prescribed methods). In our simple example above we can find formulas and strength data and crunch the numbers. We can find code books with tables and use that as a guide. We can build it then stand on it and jump up and down on it to see if it holds up. Or we can find an example in our neighborhood that is spanning the same distance and copy the member sizes and spacings, using the same materials and member shapes and dimensions.

If you acquire materials from the manufacturer then they can tell you the stresses in the tables above concerning the exact product you buy. For example square tubing. Then you may use all the methods above to determine if your design will hold up base on the manufacturer ratings.  If we are using scrap then we have to use some real common sense and experience and do a bit of investigation so that we can determine minimum strength properties.

If we calculated a flat roof with the same area as an A-Frame, Lean-to or Half-Round roof, it most likely would work fine. This is because the actual loads would be less for those designs.

Recommended Books
Machinery’s HandbookErik Oberg, Franklin D Jones, Henry H Ryffel and Christopher J McCauley
2008
Industrial Press

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The Mongolian Yurt


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The Survival Pod Cast
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What is a yurt? Is it a tent? Is it a hut? Is it a shack? Is it a cabin?  Pick up the book titled, “Build a Yurt!”  This book was written by a guy in the 1970’s that actually visited Mongolia. This web site has a nice gallery of yurt photo’s. Yurt Gallery Yurts are actually called a Ger in Mongolian. Ger means home or dwelling. It is a light wooden frame, circular like the native American Tee Pee, yet shaped more like a short grain silo. I think we have all seen grain silo’s in America. It was probably covered in hides by the Mongolian’s. They may have used some heavy cloths (canvas) as well. It was insulated with thick felt made from animal hair. They were tied down with stakes and guy ropes or chords, in the similar fashion as tents. Yurts have a sky light at the top which serves a similar purpose as the hole in the top of the Tee Pee.

You may want to read a related article Green? my blog post on the green building trend and green living.

Yurts were known to withstand hurricane strength or blizzard winds of around 90mph(144kph). They are as strong as most of our buildings when it comes to wind resistance. Since yurts are round houses they are very energy efficient to heat. Yurts consist of a frame of 1 inch(2.5 cm) by 2 inch(5 cm) or 1 inch(2.5 cm) by 3 inch(7.5 cm) sticks or ribs. These are oriented in a lattice work pattern for both the side and the roof support. Of course these can be built right on the ground or on any kind of floor and foundation. I list here a parts list for a yurt which will be 22 feet(6.7 m) in diameter and have about 7 foot(2.13 m) side walls. It will rise to about 12 (3.6)  to 14 (4.2) feet (m) in the middle. This yurt will be constructed on a wooden floor which will be about 2 feet(60 cm) above grade (ground level).  It will have one door and the sky light and possibly some windows. When completed it will have 400 square feet(37 m2) of dry floor space.

11.33 foot (3.45 m) radius. 22.66 foot (6.9 m) diameter. 403.2 square(37.43 m2) foot floor space. 71.18 foot (21.69 m) circumference. Here is a Yurt Math PDF The side walls will be built with sections of lattice. The lattice is made from 1×2’s and will be about 8 feet long. The roof lattice will be made from 1×2’s(2.5x5cm) and 1×3’s(2.5×7.5cm) The 2(5cm) inch side will be on top and laid horizontally. The 3 inch(7.5cm) side will be vertical and function similarly as rafters.

Wall Lattice

Roof Lattice

Parts list

  • 140-1″x2″x8′ (2.5cm x 5cm x 2.43m) sticks for wall lattice.
  • 70-1″x2″x12′ (2.5cm x 5cm x 3.65m) sticks for roof lattice.
  • 70-1″x3″x12′ (2.5cm x 7.5cm x 3.65m) sticks for roof lattice.
  • 3/8″ (9.5mm) steel cable 75 feet(22.86m) long (for the 70 foot (21.33m) perimeter)
  • Rope for guying. Or cable for guying.
  • 6 to 8 Wooden or Rebar Steaks
  • Turn buckles for tightening the steel cable.
  • 6 to 8 Cable clamps.
  • Small finishing nails.
  • 4’x4′  (1m x 1m) foot piece of Plexiglas (for the sky light).
  • Side covering. 8 feet by 72 feet in size.  (2.43m x 21.94m)(canvas or vertical wood or tin) Contact an awning maker for this.
  • Roof covering. This is a cone shaped piece. in 11 feet the roof will rise about 5 feet(1.52m).  (canvas or wood shakes or tin) A circular piece of about 25 feet(7.62m) in diameter might work. The circumference would need to be 71 to 80 feet(21m to 24m) maybe.
  • 500 feet (150m) of Nylon chord for tying down the roof covering, if the roof covering is made of some cloth like material.
  • Linseed oil, to be rubbed onto the lattice pieces.

Parts list for the floor.

  • 6, 6″x6″x11.33 feet in length beams size (can be larger than 6×6 such as 6×9). The angle between the outer hexagon beams is 120 degrees. The angle between the main beam across the middle and the diagonal is 60 degrees.
  • 1,  22.66 foot  6×6 (6×9)  beam.
  • 44- 2″x6″x10′ for floor joist spaced every 1 foot
  • Or 22- 2″x8″x10′ for floor joist spaced every 2 feet (if used 6×9 beams)
  • Joist hangers, metal sheeting for custom hangers, or pipe strapping. If using strapping then toe nailing is required. Do not end nail for support.
  • 1x planks for flooring. If 1×4 will need 132. If 1×6 will need 88. They will be 10 foot long. Planing and tong and grove jointing would be nice.
  • Plywood for cantilever floor support. This is for the edge that hang over the beams. Figure a 71 foot circle then draw a line from one edge of the circle to another edge which is 11.33 feet long. There will be 6 such areas.
  • 100’s of 16 penny nails or long wood screws.
  • Stone or blocking for support to lift the floor 1.5 feet off the ground.
  • Linseed oil for some rot protection (to be sprayed on beams)

Main Floor Frame Beams.

Floor with 2x6 joist on top and 2x8 joist on bottom.

An insulated floor might need these parts..

  • 6 mil plastic to be draped over the joist.
  • Fiberglass Batt insulation.
  • Or wheat straw as insulation. (if I used this I think I’d want a light weight plywood underlay.
  • Staples and Staple gun.

Other ideas..

Fly Screen might be needed on top and sides to keep insects out.

Instead of the yurt lattice for side, consider a normal 2×4 stick frame side. For the top use two layers of 1″ plywood pieces cut in circular fashion to make a wall plate or 2×4 pieces with angles cut to fit perfectly between studs. A metal top plat would work well also. Use metal plates and sheeting for extra support.

A tin roof with standing seams would be easy enough to make. Would need pieces of tin that were about half a foot wide at the top and maybe 2 or 3 foot wide at the bottom. Top to Bottom edges would be bent up at about 2 inches. You would lay these side by side then use some tool to bend the seam of the edges of two pieces over once then twice. These pieces would be nailed at the top. Something at the top would cover the nail holes, such as the plexiglass sky light cover.

Cost of a yurt?

I shopped around in our area a bit and realized the yurt frame was going to be fairly affordable. Just the frame and all the parts needed to get the frame up might be less than $500.  If you look at my article on Log Cabins you will find near the bottom photo’s of my milling operations using the Alaskan Small Log Mill, my chain saw and the Beam Machine. I calculated from that one log I could make 128 10’x1″x2″ pieces. I would probably need a table saw or skill saw to make the 1×2 pieces from 2×18 planks. And at a cost of only about $10 in fuel and oil.

I’m not sure what an awning maker might charge to make the top section and side section but material is near $4 per yard. On this first yurt we will be cutting pieces from an old revival tent. This is some kind of rubberized canvas. A person could use the clickable calculator below to calculate the size of wedge shaped pieces of material needed for a roof piece. You would enter the slope distance and not the horizontal distance for the radius in this case along with the number of pieces. To figure the shape of the round edge simply use a string nailed at the apex, then with a pen tied to the end of the string mark the arc shape for both the outside and the sky light hole. Each piece could then be cut out and sewn/glued together. This could also be used to calculate the sizes for tin roof pieces.


The wood for the floor is a different story all together. I priced this at $2500. It could be done cheaper if rough cut by some local mill, maybe $1000 or so. I bought some tools to mill my own lumber. A used chainsaw, $250. Beam Machine chain saw attachment $50. Grandberg mill chainsaw attachment $200. We plan to mill all the wood for the yurt. Not counting the cost of the milling equipment we hope to have less than $500 into this yurt when finished.

Yurt kits go for $5000 to $8000 or more.  If you have the money, the kits are probably worth every penny, though I’m sure a bit overpriced.

I am wondering why the industries of the world do not mass produce yurts and offer them at rock bottom or at cost prices for the homeless around the globe. Or at least to missionaries, peace corps and for disaster relief. The yurt is the perfect temporary shelter for any location anywhere, they just need to be shipped. Its darned arrogant to think that because other peoples around the world can’t afford a modern home that they should have to live in card board boxes or homes made of scrounged parts or whatever. The existence of living in a yurt would be rich to many homeless peoples around the world. Churches around the globe should make these for their missionaries with donated materials. Churches should be the leader in getting this type of housing to people in 3rd world countries.

How about putting yurt on stilts in a flood prone area.  It is light weight and this would be easy to do. What about putting a yurt over water?  Sure, on stilts over water, would make an awesome lake cabin for lakes with well known maximum water levels.

A ladder could be added which goes from floor up to the sky light for added support, as well as providing a view from the peak of the yurt. Maybe even a great shooting position aye?

A 2nd floor could be added which would serve as a loft. In the above design which I lay out in this article  consider an inner 12′ diameter floor where the joist of this floor is 6 feet 6 inches off the main floor. This should give 5 to 6 to 7 feet of head room. 2 to 4 people could then sleep in the loft area. A ladder would be needed for loft access. It would need to be supported by some sturdy columns. These columns may need to descend through the floor to concrete piers and footers. Bracing may also be required on the columns.

Could a yurt be made from poles for the lattice works? I’m sure Mongolians used poles. I’d guess 1 to 3 inches in diameter tree’s and limbs could work if they are straight enough and don’t taper too much.

How about a bamboo yurt? Would river cane or fishing pole cane work for a very very small yurt? Or how about combining small river cane into chords which make up the yurt poles or sticks for the lattice.

Other variations on the yurt theme. For example if its a permanent yurt, many different things would work well for round, cylinder walls. Then the yurt wood top could be used as traditionally.

Earthen walls to include. Super Adobe, Adobe, Rammed Earth, Earth Bag, Earth Tube.

How about papercrete sprayed on the yurt frame? I’m not sure that I’d do the roof section that way, but for the wall lattice this method would work nicely, and provide some insulation. Papercrete has an R rating of 2R or 3R per inch of thickness. If you couldn’t stand to cover the nice wood lattice with papercrete then blocks could be made and stacked around the outside of the lattice as the wall covering. The roof covering could then drape down over the papercrete wall veneer. I sheet and some vapor barrier plastic could be between the lattice and the papercrete wall veneer. Other variations of wall veneering might be possible too, such as the earthen methods I listed above.

Verticle Log walls can be done using a variety of  methods.

Grain Silo walls.

Steel or metal frame instead of wood?  Any kind of scrap metal might work for this. Tac weld the frame where the lattice pieces cross.  Would make a frame way stronger than the wood yurt frame. Use angle iron for the roof for at least one direction in the lattice. Flat iron could be used for the sides. How about rebar? How about Metal pipe?  PVC or Plastic Pipe filled with grout or some other material to make it rigid? And as long as we are putting up metal frames, how about gunite or shotcrete? Plaster? of course metal lathe or chicken wire might be needed.  The yurt frame and structure and design could be made many different ways if one put his mind to it.

I was told at a Genghis Khan exhibit, where they had an authentic yurt on display, that it took 10 men 10 days and 200 sheep to make the cover for one yurt. If you are interested in felting yourself, look up felting machines on Ebay. Also one can hand felt with felting needles (not me). A felting machine resembles a sewing machine in appearance. Basically all animal hairs have joints. If you wet the hair and agitate it, the hairs align an interlock making felt. Wool, Angora, Mohair and other animal hairs can be felted. If the felt is thick enough its even water proof. It insulates really well.

The way the mongols made felt was to take a felt mat and add a layer of fresh hair to it, wet it, then roll it up like a rolled up carpet. Then they would tie it to a rope and drag it for miles behind horses. The new felt would then merge with the old felt.


Update on our yurt plans. We were first going to build Gary Tuck a friend of mine a yurt. We had decided it might go good next to a good sized pond on their place. The problem we were having was in keeping the cost down near $500 for the whole project. We have had found a way to do that but it required milling quit a few logs for the floor decking and structure. Not having time for that has postponed the whole project a year. However, Gary Tuck recently found a source for free 4’x8′ pallets. I also have a brother that can get me random sized pallets for free from his business. So we have new plan.

We can get used light poles from the power company for free. These are treated so they would make great post/piles. His pond’s water level usually drop 4 feet or so in summer. So we are now planning to construct using these post a platform/deck 1.5 feet off the ground at the lowest point and probably 3 feet off the water. It will extend maybe 4 feet over the water when the water is at normal full levels. We will put in the piles, then attach some 2×4 bracing to them. We will attach treated 4×4’s on top of the pile to run horizontally as the main structure for holding up the pallets. We will staple 6 mil plastic to the underside of the pallets. The pallets will lay on top of the 4×4’s and overhang a foot all the way around on the perimeter. The area under where the yurt will be placed will have used/recycled fiberglass batt insulation stuffed in that we will take from an abandoned mobile home. We will then nail down thin plywood sub floor on top of the pallets.

Using my chain saw I will cut the 2×4’s off some of the pallets to make 1.5’x1″x4″ flooring planks. We may floor the entire deck with this. Then sand it with a huge electric buffer/sander. Then water seal it. The area where the yurt will go however will need a 22’diameter additional flooring in a circle shape. We will mark this area and lay down some additional flooring and cut it to shape with a router. Again sand it and apply water seal. This will make a deck 28’x28′ leaving 6 feet on the water side for a porch/deck that overhangs the water 4′. There will be 3′ on each side of the yurt on the sides. And the yurt will be at the edge of the deck on the land side opposite the pond. The total cost in this may go slightly over $500 maybe even up to $750. We intend to mill the lattice framework from logs. And use an old revival tent to make sides for the yurt. The roof may still be a problem. I’m trying to talk Gary into roofing it with #10 cans used as shingles. Though I’d prefer a canvas roof if we can get that cheaply enough. If we can’t then the price will go up above $750 to who knows how much more, maybe $1500.

Recommended Books
Build a Yurt
1970
Len Charney
Publisher Unknown

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Earthen Construction


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The Survival Pod Cast
Off Grid Net

earthship

Earth Ship Illistration

The Survival Pod Cast
Off Grid Net

  • Adobe
  • Hybrid-Adobe (Uses Cement and Paper or other added materials in the mix, instead of straw.)
  • Rammed Earth
  • Rammed Block
  • Earth Bag
  • Earth Tube
  • Cob
  • Earth Ship (Rammed Tire)
  • Earth Covered Roofs (Sod)
  • Dirt floors
  • Gabion

You may want to read as a prerequisite Green? my blog post on the green building trend.

This is some images of an earth sheltered design. The infil between columns in this design is earthbag, though it might be rammed block, cinder block, log, concrete and other methods. Warning this is a concept that has not been fully engineered.

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The above list all the types of earthen construction of which I have read about thus far.  What type of earth? It depends, but most of the methods call for a proportional mixture of clay to sand. All would be without loam, which is the more decayed plant like material.  Gravel and stones would not make up much of a mixture if any.

Earth may need to be stabilized. This means that it would need to be made stronger, glued together better and so that it can support more compression or weight without falling apart or mashing. This also helps to prevent cracking. Stabilizers add abrasion resistance and erosional resistance.

Wheat straw (which can be found sold as fodder or bedding for horse stalls, at the time of this writing for $4.50 a bale, bale being 8″x16″x32″) would be the most famous choice as a stabilizer in some types such as adobe or cob. Cement would be another stabilizer for types such as rammed earth or rammed block.  Lime might be another, for example in “Roman Cement” lime is mixed with clay. Fly Ash (ash from burned coal or coke) could be another as well.  Asphalt yet another.  And there are other types of stabilizers that I most likely have not mentioned in this article. Much of the advancement in stabilization of earth has come from the civil engineering in road building in recent years.

The exact construction of a given type would be shaped by the humidity, rainfall, snowfall, ice and freezing for the location of the structure.  I suppose the driest most arid climates would be most suited, however cob has been used in very wet climates such as the British Ilse. If the designer applies enough thought he may be able to use any of the earthen methods in virtually any climate.  The equation is simple. The more wind, rain, moisture that is present the more stabilized and protected the earthen structure must be made to be. None of the earthen structures are as durable as baked clay bricks or concrete.

Why use earthen methods of construction?

  1. Thermal mass properties. (It stores heat and cold well, which is good for the energy efficiency of a dwelling.)
  2. Economics (It could be near dirt cheap all depending on the situation)
  3. Readily available (Can be gathered from the building site itself or from nearby)
  4. You have access to very cheap or near free or maybe even free labor?
  5. Playing in the mud is fun? Well for boys, of course men have pricier toys and projects.
  6. Maybe you have a taste for military field style construction?

Adobe would be made from sun dried bricks of mud and straw. The mud should have the proper proportions of sand and clay. Too much clay and it shrinks and cracks easily. Too much sand and it falls apart. Adobe walls are usually about a foot and a half thick. Bricks are made to be about 40 lbs each so that they may be easily carried.  Cob is very similar to adobe except that it is not sun dried and cures more like concrete. Cob walls are about 1.5 feet thick as well and are built from the ground up by packing globs of the cob mixture onto the top of the construction over and over until it is completed. Thick paddles are used to tamp and pack the outside of the wall as you go up.  Earth bag, earth tube and Earth Ship all use normal loose soils. Ratio of sand to clay is not as critical. It is packed in place in a near dry state. It is packed into tires with a sledge hammer. Soil is shoveled into polypropylene earth bags, or long earth tubes. (Recently at a company called “White Bag Company” in North Little Rock, Arkansas I purchased 1000 polypro bags 14″x22″ in size for $160 UV Rating of 1500hours, UV rating means number of hours in full sun that the bags will take without falling apart, and yes they will if not covered in some fashion such as by plaster or earth or mud.) In the case of tubes, the tubes are run in layers coiled in a circular fashion. For earth bag and earth tube walls barbed wire is used between layers for reinforcement.Earth bags are usually staggered like bricks.

Hybrid-Adobe uses adobe mix without the straw, but adds other materials such as paper, cement, glass shards etc. Not much to say here, but I will direct you to a web site–Hybrid Adobe dot com And they have a book which I have yet to buy and read, so I can’t really recommend it just yet.

Rammed earth is stabilized with cement or possibly lime and/or fly ash. If cement it is near 10% mixture of cement to earth. Rammed earth is moistened to a bread dough consistency then packed into forms that resemble concrete forms. Rammed blocks are the same but use a machine to press the blocks. Fernco Metal has several block pressing machines.  The cheapest is $1200 and is manually operated. Blocks are similar in size and shape to adobe blocks. Rammed blocks would be stronger and more stable than adobe. Rammed earth does not include straw.

Earth covered roofs are roofs with strong frame structure supporting them, near 180 lbs per square foot strong. These roofs can be steep but need to have at least a slight slope. This next list shows the layers in an earth roof top to bottom.

  • Sod (Grass)
  • 6 inches of soil
  • Sand
  • Gravel
  • Old used carpets to protect water proof membrane.
  • Water proof membrane such as a 40 mil pond liner.
  • Old used carpets to protect water proof membrane.
  • 4 to 6 inches of Styrofoam insulation.
  • Tar paper
  • Plywood or planking.
  • Structural frame (roof support beams, rafters, joist)

I felt I at least needed to mention a gabion. A gabion is a box, cage container which is filled with loose earth or rock. The gabion container itself merely acts as a retainer.  Metal wire boxes might be used. Bamboo, or wicker containers have been used in the past. Most people have noticed these as hex poultry fence wire made into boxes and filled with fairly large stones. I have seen this used as retaining walls and privacy walls, and for erosion control. The Earthship wall is basically as set of gabion bricks where a tire is used as the “cage” to hold the earth. In earth bag the bag or tube acts as the gabion.

Dirt floors are made by layering and tamping. Gravel is used below for good drainage, then sand, then earth. The stabilization of the earth is increased the closer you get to the surface. Finally the floor can be waxed with bees wax. Also straw may be used in the layers for reinforcement.

Walls are plastered with either a cement type plaster, stucco or a more breathable lime plaster, and possibly in some cases a mud plaster.  Cement plaster can trap moisture between the plaster and the wall and should be used carefully. Plasters can be reinforced with fibers or animal hairs. A lath may be needed to hold the plaster in place or for reinforcement of the plaster. A lath is a rough grid like surface by which the plaster can adhere too. This can be chicken wire or specially made lath. In times gone by it could have been wooden lath. In waddle and dob it was made from thin branches woven together.

Now I will talk about some of the book resources available. Most of the adobe books I found (and there are quite a few on adobe) seemed to be very good all the way around. One that I found was on the repair or restoration of old adobe churches and homes. The one book on Cob I found was very good and covered earth floors and a Cob bread and pizza oven. Rob Roy has a book called “Earth Covered Shelter” which is a must have. I have seen one on earth bag listed below but have not bought it yet, though it looks very nice and comprehensive. There are 3 books on Earth Ships written by a hippie environmentalist architect. Those houses are architecturally sound and are simple to construct. However I feel that the tire wall thing is kind of risky in any climate but a very arid desert like climate, especially the way the author uses the ground itself in places and merely plasters over the ground. I have the engineering text book on Soils and Foundations and have so far found it to be invaluable source of general info, even if you don’t work the formulas, as with many college engineering level books. It goes a long way in letting you understand exactly what kind of dirt you are dealing with.

However after much thought I have found ways in which the tire walls could be constructed in very wet climates and be made to be waterproof. This adds to the construction time, cost and complexity. For example the walls would have to extend all the way to the grade over the entire U module, and the base of the walls would need to be above grade. You would need very good gravel drainage, possibly a pond liner and french drains to protect the wall and berm from water penetration.  Also something like a cavity wall could be constructed between the tire walls and the berm or embankment (hill side). A cavity wall is merely two walls with some space between them.

None the less I personally would consider using tire walls for any non living space such as storage, shop space, garage space, barns, sheds, animal shelters, retaining walls etc. in wet climates. In wet climates for living spaces I would go with 2 to 3 foot thick walls made of Brick, Block, Rock, Concrete, Earthen or Earthen core with any of the other methods as a box or perimeter or surface to contain the earth core. Also remember that with a wall of this size the footing will need to be very huge, maybe 2 feet deep and 8 feet wide.  The U shape of the Earth Ship module can be more square in shape but this might reduce the strength of the design somewhat. Reinforcement bar may need to be added to strengthen the design so that the U Shape for non-tire walls would be comparably strong to that of the tire walls.

One particularly interesting document I found was produced for the Peace Corp. It is called “Handbook for building homes of earth”. It goes into some very good detail on soils and stabilization of soils. It goes into great detail in telling you how to determine clay content. It covers how to test compressive strength. How to test for abrasion resistance and erosional resistance with a spraying test.  I found this as a PDF on the web, but also it can be bought as a book. Earth adobe blocks or cob walls end up having about a 150 to 200 psi strength. Rammed blocks maybe 350 to 400 psi strength. Compare that to concrete block of 2000 psi, or baked brick of 4000 psi, or concrete at 6000 psi or granite stone at 15,000 psi or steel at 25,000 psi. Wood from the top of the post pressing downward is about 10,000 psi. Soils can be any psi up to hundreds of psi. Usual soil strength might be 50 to 70psi. Of course moisture in soil changes a lot and makes a huge difference. More moisture typically reduces compression strength. Earth walls are wide however which means they spread more roof weight over a larger area.   An earth wall that is 1.5 feet wide will support nearly 43,000 lbs per linear foot. A concrete block wall 8 inches thick will support 191,000 lbs per linear foot. An earthship tire wall (3 foot thick) would support 100,000 lbs per linear foot or more. So you can see that the earthen walls, though being the weakest in pounds per square inch, do have strength for supporting roof structures.

By the way would anyone know what the EPA thinks about using trash or tires as a construction material? EPA will mandate strict disposal of waste tires. I think though if the tires were used in construction they then become a construction material and not waste. And a last note, remember that anything slightly underground or earthen in wet, humid climates may sweat, or collect dew or otherwise be moist. Therefore in living spaces or environmentally controlled spaces de-humidification would be necessary. The good news is that the energy cost for de-humidification will be half that of the standard A/C and you might get grey water which can water plants or even drinking quality water from some dehumidifiers. Eco Blue is one such dehumidifier. Passive dehumidification can be achieved by setting containers of rock salt here and there. The rock salt can be cooked to remove moisture and then reused. Damprid sells some rock salt type dehumidification products that let water in and will not let it escape back out.

About earth roofs and berms: One way to protect from water penetration is pond liner. The other is Bentonite or other clay layer. You can get clay in sheets I think. If you are really serious use clay on top of the pond liner. Or clay directly beneath and on top of a pond liner. Clay can actually self heal if it gets a small hole in it.

Recommended Books
Handbook for Building Homes of Earth

Earthship Volume I

Earthship Volume II

Earthship Volume III

Building with Cob

Adobe Conservation A Preservation Handbook

Earth Sheltered Houses
Rob Roy

Earthbag Building
Donald Kiffmeyer

Soils and Foundations
Cheng Liu, Jack B. Evettr

Also see my web sites larrydgray.net and arksoft.org

Please Visit Christian Forums


Timber Frame, Post and Beam, Beam and Stringer.


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Of the books on the market for Timber Frame construction that I have seen only one slightly impressed me. “Timber Framing for the Rest of Us” by Rob Roy.  As a matter of fact all of his books have impressed me so far. Most of the books on the market are picture books that tell you about Timber Frame homes.  They are mostly to get you interested in having one built for you. Rob’s book goes into some good detail about the simpler frame construction and design. He also uses homes he has built as examples. He tells you how you can mill your own beams and other interesting details. He gives you some very basic information in regards to the engineering of beam size for floors or roofs. None of the books go into how you design or calculate the strengths in a frame.

You may want to read as a related article Green? my blog post on the green building trend and green living. And a related article Log Cabins in which I talk much about logging operations.

Most homes in the USA are Stick Frame, meaning 2 inch by so many inches sized lumber in construction.  Timber frame means structural frame made from beams or post that are larger than 5×5 inches in dimensions.  You probably think of Amish or maybe Mormon made homes when you think of timber frame.  Why are most homes not timber frame?  Large trees are difficult to come by in many areas, therefore beams or logs must be imported. Not a lot of builders specialize in timber frame and are therefore not extremely skilled or efficient at this type of construction. Also if you do not have some nice blueprints or design specs for a frame you want to build, then you would have to possibly hire an Architect or a Structural Engineer to design the frame. And if you want old fashioned joinery with wooden pegs an Architect or Engineer may not even be able to help because they only have calculations which deal in metal bolts, pins and plates for connections. When constructed under code restrictions beams must be graded, so that means you must either buy them as pre-made, pre-graded beams or if you mill them then you must find someone to grade them.

In the past history of this kind of construction most frame designs and construction details and joinery were handed down generation to generation.  Copied construction designs and use of the same species of wood generation to generation meant being assured that the structure was sound, as it had already past the test of time. Today if you are designing the frame from scratch then you are probably a structural engineer. You would have a text book to guide you in calculations which would determine the strength of any kind of design you choose. I’ll list some sources of information relating to this.

  • National Design Specifications
  • International Building Code
  • Timber Construction Manual
  • Uniform Building Code (Western USA)
  • Standard Building Code (South Eastern USA)
  • National Building Code (North Eastern USA)
  • Design of Wood Structures (College Text Book)
  • Lumber and Forestry Associations also have information.
  • Lumber Producers have information.

Now did that just scare the living poo out of you? Yes wood is not a simple material to work with at all on the scale of timber frame, post and beam, beam and stringer. Its not even simple in furniture. You certainly want to make sure your design is safe for occupancy. Even engineers make mistakes right? When human lives are at stake the design details are all the more important. This is why architects and engineers are paid the big bucks. However I must say that after reading the text book, “Design of Wood Structures”, I have begun to really get the jest of what is going on when they calculate the strengths of a given design. Though I have not worked the problems myself.  Merely reading that book has greatly broadened my overall understand and comprehension of the nature of wood and working with wood.

So how do they determine the strengths of a piece of wood? In a lab they gather 100 high quality identical samples 2x2x30 inches of a given species of wood for testing. They stress each piece with equipment which show the pounds of pressure or stress per square inch that is being applied. They stress each piece until failure.  100 recordings are made. The list is sorted least stress to greatest stress. The lowest 5 are thrown out, so that the wood is determined to fail a the 95th lowest value or greater. In formulas a safety factor of 1.25 is applied depending on the method used to calculate the safety. One method uses 1.25 another uses a more situational dependent value for safety. Anyway the value which goes in a table for the strength of the wood is the 95th lowest value needed to break that wood times a safety margin of 1.25. This is called a design reference value. It is specified in pounds per square inch for  compression, tensile, bending and other types of stresses. An engineer will get these design reference values mostly from the National Design Specifications.  Phew, I hope I explained that clearly enough.

Stresses become a lot more complex with wood than pounds per square inch applied in vertical compression. I don’t even want to go into it in this writing. Probably the best that the common individual can hope for practically is in calculating floor loads and roof loads on floor joist and rafters.  Aside from that please go find a qualified structural engineer or copy very strictly some design that has already been engineered and tested. Where you might find pre-engineered designs?  I have no idea, maybe a reader can clue me into this. One way might be to examine a structure which has been standing for 30 years and simply copy its design, making sure that you are using the same species of wood. Over-engineering can work where feasible. Use the formula variable P for Plenty. Though I think without a good measure of common sense and some prior wood working experience and some study, self engineering is risky business.

I think in my case if I do my own calculations for use of timber in a structure, the structure will either use timber only for a floor or roof, not walls and not for holding up the floor or roof. Or it will be for simple symmetrical one story designs, (Post and Beam).

Personally I still can’t help but love the look of timber frame. I can’t help but try to imagine how timber frame, or at least beams might fit into my own construction designs and projects. Some advantages in using timbers are.

  1. I can make my own beams.
  2. Fewer pieces are needed in the structure.
  3. The structure has the look of impressive long lasting strength.
  4. The structure is on display and can always be inspected for its integrity.
  5. Varying types of infill for walls can be used (Earth, Straw, Stone etc.)

Regardless of engineering complexity, I personally will continue to study how to engineer with wood. As I learn more, I learn more about what I may be capable of and when I must say, “Nope, we would need an engineer for that.”

A last note. I have been told the best chain saws are Husqvarna and Stihl. Husqvarna parts are easier to find I hear. Stihl has been recommended as the absolute best however. Saws of around 100cc or 10 horse power are best for milling lumber. Run them at 90% throttle if possible. Sharpen the chain often. Use good oil. etc. A special chain called a rip chain may be needed and can be purchased from grandberg.com.

If you visit Lee Valley’s web site you will find a wood working catalog and near page 200 will be a thing called a Beam Machine. It cost around $50. This is a very simple guide tool. It is shaped like a 2×4 in order to fit over a 2×4 so that it can slide back and forth along the board. This uses the board as a straight edge. The board would be nailed to the log.  There is a C or U shaped clamp on the side of this bracket with 2 bolts. These bolts tighten up on the chain saw bar so that the chain saw bar is held at a 90 degree angle to the flat side of the 2×4.  There is also a small bubble level on the bracket. The chainsaw bar is kept at a perfect angle as it is moved along. Once you get one side sawn, simply rotate the log 90 degrees and move the 2×4 to the flat side. Then saw of the next side of the beam. Repeat this 4 times and you have a beam. I am about to give this one a try myself soon.

Also at Lee Valley or grandberg.com you may buy the Granberg Mill. This mill would be a jig or frame that completely supports the chain saw. It supports the saw on both sides of the log. The top of this frame has rollers which roll along on the log or on a board which is nailed to the top of the log. The frame holds the saw a given distance beneath the rollers.

One of the more inexpensive type of highly portable band saw can be found at lumbersmith.com for around $2200. And one more tip, you may be interested in getting what is called a Log Arch for moving logs around your lot. This can be pulled behind a four wheeler. It moves one log which is chained up and suspended from the arch and boom.  This can be easily made or purchased for around $700. I talked to a trucker from West Virginia at the time of this writing who told me that the going rate for Logs (as logs) were $0.30 to $0.45 cents per board foot.  He said that standing timber would be about 40% of that cost. Personally I don’t intend to do the logging. And at least one author has agreed with me that if you are not a professional logger then its probably best to stay away from this. I do intend to fell some trees myself and cut boards/beams from the logs at the felling location. I might haul one or two logs per run sometime if I feel like it. I followed a 16 foot dump truck around Atlanta Georgia one day. He had a load of good sized 24″ diameter or better logs cut just long enough to fit the dump bed. He pulled a trailer with a bobcat and a stack of plywood. I assume he used the plywood to make a ramp for rolling the logs into the dump bed. He probably used ropes or chains and the bobcat to get the logs into the dump bed from a ramp on the side. I’m sure he used the bobcat to maneuver single logs into position for rolling up the ramp one at a time.  If you are in a position where you might jump and run 24/7 think about finding some excavators.  Excavators are constantly pushing down trees simply to burn them in dozer piles.  They could possibly give you the logs/trees. They would even let you saw the lumber at the site most likely.

Stick Frame  2×4 2×6 2×8 construction.

I only want to say that the book, “Design of Wood Structures” covers engineering of this kind of construction really well. Engineers can certainly calculated the load bearing capacity of 2×4 walls. They can certainly calculate the load bearing capacity of various truss designs. A more modern type of truss design is the plywood or particle board I Beam. This is made by using a sheet of plywood that is say 20 feet long and only say 3 feet high. 2×4’s are nailed on each side at the top and bottom of the plywood. Joints are staggered. 2×4’s are nailed on each side over plywood joints.  This is a strong truss for flat or near flat roofs and floors. When plywood and sheet rock is nailed to the 2×4 wall/ceiling/floor frame it is called sheathing and acts as a “diaphragm”. Both structural board (plywood and osb and particle board) and sheet rock act as a continuous brace for all parts of the frame.  With close nail, screw or staple spacing (schedule), this forms a very rigid and strong structure.

Fasteners and Plates

The book “Design of Wood Structures” also covers plates and fasteners in very good detail. Plates are a fairly simple matter. Any stress on the metal plate will simply be trying to tear the plate and therefore puts it in tension. All one needs to know is the tensile strength of the plate for the given type of metal and thickness. Fasteners though are a lot more complicated. The book covers bolts, lag screws, screws and nails. Fasteners over 1/4 inch in diameter are large dowel type fasteners and need pilot holes or pin(bolt/dowel) holes. Fasteners below 1/4 inch in diameter are small nail or screw type fasteners and need no pilot holes. When using the larger type of fastener the computations and considerations become more complex. For example the strength of the member may need to be recalculated minus the area of the pilot hole or pin hole. Also angle of load to grain is figured into the calculations. Crushing strength of the wood members must be considered. This is why nails and screws are so popular. Some kinds of nails have greater withdrawal strength than others. Though in most connections withdrawal is not a consideration or much of one. Screws of course have the greatest withdrawal strengths.

All metal dowel type fasteners have a strength property know as yield limit. This is the pounds of force needed to bend the fastener. Actual shear or failure is not calculated because the fastener will bend or withdraw long before it ever breaks. Basically there are 6 modes of failure(bending and withdrawing and crushing) for every connection type.  The engineer will calculate all 6 modes and use the mode with the lowest failure strength for the final value. It could work out that anyone single mode might be the lowest.

Anyway lets say you find that a bolt would hold up 100lbs as its lowest mode of failure. If you have 2 bolts then the connection will hold 200 lbs. If four then 400lbs etc. Same for nails or screws.  Also washers and plates will prevent bolts heads and nuts from pulling through the wood member because they distribute the load over a wider area.

More…

Of course there is more to it than this. Each calculation can be modified based on many different sets of criteria. For examples wet vs dry service. Moisture content of the wood. Repeated loading. Impact loads. Terrain modifiers. Occupancy categories and so on. There are factors for wind, snow and seismic loads. To thoroughly engineer the structure two different systems must be calculated. One is for lateral loads, called the lateral force resisting system. The other is the vertical force resisting system. In the lateral system sometimes walls and floors change roles. Yes joist and rafters become post. Lateral of course are wind and seismic loads. In an earthquake you have cantilever forces in play as if the ground was turned on its side 90 degrees so that it was vertical and the structure is hanging from the foundation like a shelf on a wall. In this wall/shelf example inertia is the force acting on the shelf (building) and not gravity.  And in wind, braces may be in compression one moment and tension the next. Most homes are designed to withstand 80 mph winds.

Stresses or forces at play in a wood frame.

  • Compression (crushing)
  • Tension (pulling)
  • Torsion (twisting, I only mention this, its not usually a consideration in wood construction)
  • Shear (tearing, cutting)
  • Bending (Bending Modulus or Moment, as in beams, rafters, joist)
  • Modulus of elasticity (pliability)
  • Cantilever (overhanging)
  • Axial (along an axis, such as in post and braces)
  • Self Straining (from shrinking)
  • Creep (deformation from repeated loading)
  • Deflection (bowing due to temporary loading)

In wood you need to remember that there are different values for all of these forces across grain vs with grain, and longitudal (top to bottom). The book “Design of wood Structures” covers all the do’s and dont’s when it comes to loads to grain considerations. It cover’s all other hard earned do’s and dont’s for just about everything that can be thought of. You might call these rules of thumb.

To keep things simple, lets say that the engineer is going to calculate the vertical force resisting system (vertical loads) of a wooden frame. He will divide the structure into minor tributary areas, then combine them along lines or points. Line being a joist or rafter, point being a post or brace. The forces actually flow from the very top of the roof down to the foundation in very much a similar fashion as water flowing from streams to creeks to runs to small rivers to larger rivers to lakes or seas or oceans. Tributary area is a great metaphor for describing flow of forces. And its a great way to break down the problem. Forces go from pounds per square foot on floors and roofs to pounds per linear foot on joist and rafters to pounds per square inch on post and foundations.

What software could one use?  The mighty spread sheet would be the main tool. Special software for this purpose would have to be carefully made and certified by qualified people. I wonder if this is why you do not find free engineering software. Liability might be a huge problem when human lives are at stake. If I get time I will write some software for my own purposes for specific design problems but I probably will not be sharing it.  Once a spreadsheet template has been setup for a given design problem however that one template can function again and again for different projects with little or no change. A good free spreadsheet can be found in “Open Office”. Simply google for “Open Office”, download and install it. They call the spreadsheet Open Office “Calc”. There is also and Open Office “Math” but I think this is only for constructing formulas visually for documents.

Types of Joinery that I have read about or heard of by name…

  • Mortise and Tenon
  • Open Mortise and Tenon
  • Blind Mortise and Tenon
  • Stub Mortise and Tenon
  • Through Mortise and Tenon
  • Step Lapped Rafter Seat
  • Single Shoulders
  • Double Shoulders
  • Joist Pocket
  • Lap Joint
  • Through Half Lap
  • Mortise and Tenon with Diminished Haunch
  • Dovetail
  • Dovetail Lap Joint
  • Lapped Half Dovetail Collar Tie
  • Rectangular Tenon
  • Square Tenon
  • Wedged Dovetail Tenon
  • Birds Mouth
  • Soffit Tenon
  • Housed Lapped Dovetail
  • Half Lap Scarf
  • Stop Splayed Scarf
  • Bladed Scarf

Decorative Treatments

  • Gunstocks
  • Flared
  • Tapered
  • Splayed
  • Truncated
  • Embellished
  • Beveled Edges
  • Camphors
  • Beads
  • Dressed Shoulders

Some ideas for lifting or raising..

  • Shear Poles
  • Gin Pole
  • Derrik
  • Block and Tackle
  • Pike Poles
  • Capstan
  • Windlass
  • Tread Wheel

Some tools of the trade

Some of the names of the parts of frames.

  • Rafters
  • Collar Tie
  • Plates
  • Braces
  • Girts
  • Girters
  • Post
  • Joist
  • Cross beam
  • Bent
  • Walls
  • Ridge Pole/Beam
  • Front Plate
  • Top Plate
  • Summer Beam
  • Corner Post
  • Chimney Post
  • Dragon Beam
  • Seal
  • Major Purlin
  • Knee Braces
  • Dowels
  • Jettied Post
  • King Post
  • Queen Post
  • Hammer Beams
  • Pendent
  • Bracket
  • Gunstock Post
  • Joweled Post
  • Tie Beam
  • Ridge Beam
  • Principle Rafter
  • Common Purlin
  • Cape
  • Anchor Beam
  • Chimney Girt
  • End Girt
  • Studs
  • Bays
  • Isles
  • Full Plate
  • Nailers
  • Shakes (Wooden Shingles–3 foot Riven boards)

Common Design names

  • Salt Box
  • Cape House
  • Two Story Colonial
  • Banked Colonial
  • Gambrel
  • Federal
  • Georgian
  • Greek Revival
  • English Barn
  • Dutch Barn
  • Hip Roof
  • Gable Roof
  • Clerestory
  • Lean-to

This next set of photo’s shows the operation of the Grandberg Alaskan Saw mill. I am using my Husquvarna 55 with 18″ bar. It took about 30 minutes to saw off that first side. I was resting me and the saw a lot. It really moves along a lot faster than that. I bought two 10 foot 2×4’s for the straight edge. I intended to cut 10′ boards from this old dried elm stump. I realized after I finished that I really needed 12′ boards instead to hang over 1 foot on each end. However 9 feet or so is all the practical length I can get from this log.Next I intend to cut of at least one side or maybe both with a tool called the Beam Machine and my chain saw. Then I will cut 2″ planks from this log.

I demonstrate the use of the Beam Machine which uses a single 2×4 as a guide to cut off the side of a log. I realized after I started that I should have been 1″ further in. It looks to me like lumber could be made using this Beam Machine. If you didn’t want to use the lumber made this way for your home then it could always be used for barns, chicken coops and dog houses.

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Recommended Books
Design of Wood Structures
Timber Framing For the Rest of Us
Timber Frame Construction
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Green?


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The Survival Pod Cast
Off Grid Net

Green?

What is Green and what does it mean? Of course it is a color, in the modern context it means “Earth Biosphere Friendly”. Green has meant in the past “Money”.  It has also meant “New, Fresh and Unskilled”.  And how about “Nausea” or “Extreme Fear”? Maybe it means saving the world from “Global warming” to some. To me it means “Energy Efficiency” in architectural design of buildings and “Saving Money” each month on energy bills. It can mean reduction of monthly living cost.  It can mean a measure of independence gained. It can mean measure of sustainability. But not without a cost. Not without investment.

I have looked into various types of green building.  Earth, Straw, Insulated Concrete Forms, Masonry and Concrete, to name a few. Underground, Earth Covered and Passive Solar shelters, to name architectural designs. Some energy efficiency features are “Passive”, meaning they require no effort and no energy consumption. Others are the opposite, “Active”.   Some features may be operated manually, while others automatically.

Warning this is a concept design that has not been fully engineered.

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Is dirt really “Dirt Cheap”?  Maybe, maybe not.  Earthen structures may require more labor, however less skilled labor and less complex design. Some types of earth structures and straw bale structures are susceptible to damage from moisture and water more readily than conventional materials. Proper waterproofing will raise construction cost and complicate the design. Automation control will increase cost and energy use in any active systems. Green features will increase the initial cost, overall cost and possibly complicate the design.

How much extra cost there are will depend on the individual builder, the location, the situation, the feature and the day and time. How soon energy efficient features will pay for themselves is highly situational dependent. Obviously on the North American continent these types of homes pay off more quickly in the arid Southwest than anywhere else. But one thing is for sure. A dwelling can be made to be far more energy efficient than the typical conventional dwelling. Monthly energy use can be reduced. In the end its up to the individual to decide if it is worth it or not

There are about 4 factors that make a dwelling more energy efficient than the traditional insulated box (a mere refrigeration unit).

  1. Use the sun a lot more for heating in winter.
  2. Use the earth a lot more for heating in winter and especially for cooling in summer.
  3. Use heavy insulation in the ceiling area.
  4. Use thermal mass as a storage medium for heat or lack of heat(cold). (This is the most important feature.)

Thermal mass is to heat what the battery is for electricity and similarly it is charged and discharged. The good news is that unlike chemical batteries for electricity thermal mass usually doesn’t go bad and need replacement.  Thermal mass would basically be any dense material. Metals work best but are are very expensive for this purpose.  Water works great. Earth, concrete, brick and stone are more reasonable choices. Where do you put this thermal mass? Mainly the walls, very thick walls. Could also be in the roof as in a roof pond. Or barrels of water placed here and there.  The floor could serve as thermal mass as well.

You can do the math. One BTU is the heat needed to raise one pound of water one degree Fahrenheit. 100 gallons of water (8 pounds per gallon) raised 1 degree is roughly 800 BTU.  In space solar intensity is about 450 BTU per square foot per hour. On earth when the sun is shinning bright on a surface which is perpendicular to the sun near the noon hours a surface will receive about 350 BTU/hr. This varies and can be much less in winter as low as 100-250 BTU/hr maximum for during the day.  But lets say you have a surface that is 10×10 or 100 ft2 and it is receiving 100 BTU/hr then it gains 10,000 BTU in that one hour.  To raise one cubic foot of air one degree F, you need roughly 0.018 BTU.    A 10 foot by 10 foot by 10 foot area of air is 1000 cubic feet. Raise that area one degree and that space has gained 18 BTU. A typical window A/C Unit might be rated for 5000 BTU/hour.  A typical home heat pump might be rated for 1 ton (12,000 BTU/hr/ton).  A kerosene floor shop heater might be rated at 150,000 BTU/hr. The question that I have is, how fast would a given type of thermal mass absorb or radiate heat? I don’t know the figures here, but I assume that would be based on the specific gravity (density) of the material. How much total absorption would also be based on the surface area of the material or its container.

There is more to the overall design than this. Auxiliary heat and cold air may still be needed. De-humidification may also be needed.  Vents, and Sky lights may have some positive effects if used properly. Extra shading, operable shutters, curtains, and movable insulation may be needed. Reflectors may help with solar gain. And in the end some of this may require manual adjustments to be economically feasible. Automation is not without additional cost.

Now, on a sad note,  our system for getting green houses(or any houses) built and insured may not support all of the green features, or even the entire project.  Building Codes may restrict what can be done if your building site is not located remotely where there would be no or little regulation.  Insurance may not cover extra cost of the extra features.  The market may not accept the extra features. And banks may not loan on these extra features.  Great system huh? Its against energy efficiency! Not by design however. I feel that it has simply evolved that way.

In conclusion I say that I feel it is worth it to consider every energy saving feature that could possibly be available to the home owner and even worth reconsidering upgrades over time. If you really strongly desire a truly energy efficient home, build it with cash as you go. You may have to  go to some extremes to be able to do this, but in the end any savings you might achieve from owner building and using cash as you go will more than make up for the extra cost of the green features. This also means that as you build it and begin to live in it, you get savings in your pocket immediately. It pays off right away.  As an investment that you can liquidate, the picture might not be so pretty. A home that is too far from conventional design and from what the general market expects may be hard or impossible to sell or be sold at a loss.  That said I still feel that it is worth considering as long as you use cash and not credit for the construction. For example it could always be rented and with no debt against it, it would mean low overhead and good income.

Oh and my opinion when it comes to power production and the green scene? I am for Solar, Wind, Hydro and Nuclear, and against all other forms of commercial power production except in emergencies or periods of peak demand. I feel that its a great waste to use coal or gas for power production. And nuclear has actually proven to be very safe. Sure we have this depleted uranium problem. But the truth of the mater is that our transportation system is far more destructive to human life and the environment than nuclear power will ever be and you don’t see the environmentalist winning about it? They drive their cars don’t they! Nuclear as far as I’m concerned is a green power technology.  The demand for power in the world is only going up and nuclear is the only one that can fit the bill. Fusion power is just around the corner though. I hope to see that in my lifetime.

Great, just as I say Nuclear is a green power tech Japan has an earth quake and tsunami which washes out a nuke plant. The worst of what happened was the spent fuel pools being washed. Generators that power pumps went offline and cause cooling water to stop flowing. This caused the water in the pools to boil dry. Partial meltdown of reactors and spent fuel has occurred. The reactors are designed to contain a full meltdown. They are designed to spread out molten fuel to a degree in which it either cools down completely or enough so that it doesn’t burn through the concrete and deeper into the earth. The spent fuel pools are not under this containment. My question is why not? I would guess because of expense. Lets hope this incident does not do a lot of damage. The media has been saying that radiation has been found in water, fish, milk etc. But this isn’t exactly right. Its contamination, which causes radiation. If something is hit with radiation and the radiation is removed then that thing does not emit radiation and is not radioactive. Unless it is contaminated with radioactive particles. Radioactive particles move around via air and water. Contamination is like a radioactive dust. So they are not detecting “radiation” in food and water but contamination which emits radiation. Even with this scare if you looked into it, you would see that the nuclear industry has a great record for safety. I am thankful that concerned people monitor it closely. We just need to spread this kind of concern to everything else in life.

Recommended Books
Passive Solar Energy Book

Passive Solar Construction Handbook

Also see my web sites larrydgray.net and arksoft.org