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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.
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)
- 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.
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.
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.
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.
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.
- Logging Chains.
- 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.
- 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)
- 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
Wood Roofing Equipment and materials
- Mallot and Froe (for splitting shakes ‘wooden shingles’)
- Riving Horse
- Shaving horse
- Draw knife
- Weight Poles and struts (for weighting wood shakes down until they dry)
Standing seam metal roofing equipment
Beam working equipment
- Draw Knife
- 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.
|The Classic Hewn Log Home2005Charles McRavenStory Publishing|
|Old ways of working wood|