Hello, Im tinkering with an idea in my head, and would like some input. I think building a round vertical log cabin on a stone stem wall with embedded steel strips that would be bolted onto the log bases then I'd have about 6' of vertical log with two 2x6 boards nailed out of the top with bracing. The roof would be yurt style with a central ring and radiating poles that would come down to sit in the boards atop the logs & loosely bolted into place (I want the structure to be able to flex as I'm planning on either getting land in the PNW or Alaska & both get earthquakes). I may carve a channel into the top of the logs (but Ideally hidden by the roofs eaves) & run a steel cable that can be tensioned to provide some compressive force inwards. The logs would be swedish couped with each convex log face fitting into a corresponding con cavity on the next log. I'd chink the logs with a slow drying earthen plaster (probably a "typical" cordwood mix) on the outside & inside. I've never seen a round vertical log cabin, so I'm apprehensive im missing something. Im also curious about what would be a good minimal-concrete foundation for such a structure.
A couple things to watch out for with vertical/pallisade style log buildings:
1) End grain on the sill is a great place for rot to start, more vulnerable than a traditional log cabin... and with the horizontal cabin you are looking at one log to replace, not a piece out of every log!
2) As the logs dry and shrink, a horizontal cabin will get shorter. Ya, there may be some uneven shrinkage, but at least a portion of it is likely to balance out and leave you with a slightly shorter building.
With vertical logs, there is not going to be any helpful settling to hide the shrinkage.. just vertical gaps. Lots of em.
Using very dry wood seems more important than normal to me, for this reason...
Do you plan to insulate, and how?
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thank you for the input. I'm aware of the problems with rot at the log bases, I'm hoping the stem wall, a generous roof overhang, and curing the wood properly should prevent that. For insulation im planning on using either sawdust & lime or hemp hulls & lime in between the logs & the interior walls, which will be a earthen plaster over a bamboo lattice, im also planning on hempcrete blocks between the floor joists for floor insulation.
I think you are multiplying your difficulties,
Logs laid on their side can be fastened every 4 - 10 feet and gravity works to hold one on top of another, Palisades will require a connection every log, 6 -18 inches and gravity will work evenly allowing wood to warp in any direction ...that is some will bow in, some will bow out, and some will put pressure on their neighbors.
At the least it seems like a re-chinking nightmare.
In conventional construction the logs provide their own bridge for lintels and other openings, at the least, headers will have to be massively increased to support the vertical weight above .
While the compressive strength of the wall may be increased I have severe doubts that the increase will be of any utility.
In the case of earthquake you are entirely dependent on the mechanical fasteners holding the logs together conventional construction has gravity holding it together and can be reinforced by geometry (interleaved walls at angles), Palisades have an inbuilt shear line at every intersection..
Nothing is foolproof to a sufficiently patient fool!
I hate people who use big words just to make themselves look perspicacious.
Nathan, one can do almost any style with logs; it is just a matter of the hardware. Have you seen the price of hardware these days? Sometimes the bare fact that something can be done does not mean that it ought to be done. I have built various structures, all round timber. For me, personally, I discovered that I become unhappy with a project when I begin to pour time and money into aspects of it that really do not do much except for the structural integrity of it. It all depends on how badly you want something out of the ordinary. Throw enough money at something and you can probably pull it off. Earthquake zones can be expensive enough to build in using the old tried and true methods topped with earthquake features. So price out what you want and take it from there.
Why is it important to you that the logs be oriented vertically, Nathan? I don't see the advantage, and Bill et al. have pointed out a number of detractors, some of which might be cost-prohibitive to address with the logs standing on end.
I love the idea. Of course, when I started into the brief, I had it in mind that you were thinking tower instead of yurt, and I have wanted a tower ever since as a young reader I got lost in David and Leigh Eddings' worlds of fantasy.
It occurs to me, though, that, short of getting a livingspace high up off the ground, like a watch tower or water tower structure, where there's a lot of airspace underneath, and the structure is its own separate pod, the structure you're suggesting, or even the log-cabin tower I had started envisioning (thanks for that, by the way; now I'll have to build that, too) is better constructed as a conventional log structure with horizontally-laid logs. If you wish a round structure, the effect can be achieved by using a many-sided polygon. Octagons are by far the simplest, mathematically speaking, or at least that's been my experience, working with materials that, oftentimes, are based on a 4'x8' standard.
By the way, one reason why end-rot was less of an issue for your typical palisade construction was that one end was invariably buried several feet in the ground. No oxygen, no rot. And that's before they started using lime or wood ash to preserve the post ends.
As to end-rot prevention, I am currently playing around with ideas for converting a heat-based paint scraper into a yakisugi tool. I haven't seen it done that way, but I honestly haven't seen a wood preservation method I like better than charring large pieces under controlled circumstances such that the structure remains sure, but the few millimetres of char on the surface inhibits all microbial growth.
In any case, please keep us posted, and best of luck to you.
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