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rms344
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# Posted: 20 May 2014 12:29
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Hi all,
If you have a saddle notch log cabin and cut out holes in the walls for door or window frames, how are the logs stable if they are only structurally supported from one end? Is the compression from upper logs enough or so you have to spike them to the log courses below? If spiking is required is there a rule of thumb for their spacing? This seems especially apparent for if you have a door and a window on the same wall so the middle logs are totally unsupported except from the bucks and compression.
Thanks!
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leonk
Member
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# Posted: 20 May 2014 14:05
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you could have a look at int log builder association rules or whatever they call it, it has to be covered.
Personally if the logs are fitted properly, I'd only spike the 'short' logs in walls under 20' long. I'd use wood for spikes, though some people use metal (what if the wall needs to be cut in the future - who knows where the spikes are..?)
Plate logs and roof structure is another area of consideration.
Traditionally log homes had heavy roofs that held everything in place by weight.
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Don_P
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# Posted: 20 May 2014 19:09
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You can put a washered spike through a slot on the buck to allow settlement, or you can kerg the ends of the logs and have a piece of angle iron attached to the buck with a leg into the kerf, again holding alignment but allowing settlement, or you can create a T section buck by nailing a 2x2 to the face of the buck that slips into a 2x2 groove cut in the ends of the logs, again allowing settlement. Or in a non settlement chinker it was not uncommon to see 1" pegs driven through the bucks into the ends of the logs. It was not uncommon to see the corners low (settled) and the bucks holding the middle portion of the wall up on these.
And yup I've managed to cut a 10" lag bolt in half lengthwise, the 10" way, when a window got moved.
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Malamute
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# Posted: 21 May 2014 19:17 - Edited by: Malamute
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I inlet a 2x4 into the log ends in window and door openings. The door or window jambs are screwed to the splines only, keeping the wall logs stable, and allowing for settling.
Like this, http://outlands.tripod.com/images/logcab5.jpg
That's inlet with the 1 1/2" face exposed, going into the wall the 3 1/2". I make the cuts up into the log at the top end, and flatten the log on the bottom for the lower edge, and the spline inletted into the lower end also. Very dangerous saw work, repeated plunge cuts into each end to get the kerf cleaned out. A small saw you can man handle better than a larger powerful saw seems better to me. Makes a very stable wall though, that will settle properly. Wear your hard hat and safety gear, even if you don't normally.
If you spike the walls, the upper log should be pre-drilled to be free floating on the spike, or they will keep the walls from settling properly.
I also drill 5/8" holes a foot on each side of every opening and drop a 1/2" steel rod down in the hole to help stabilize. and bolt the walls together with allthread near each corner, and the ridge to the walls. May be overkill, but it would take a very severe quake to move it much. I had a 2' and 6' drill bit extension made for that.
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