Author Topic: 12' High Log Walls?  (Read 301 times)

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Offline IHDiesel73L

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12' High Log Walls?
« on: October 20, 2021, 07:15:03 AM »
I'm going to be constructing a 16' x 20' guest cabin/office on my property.  No construction code to worry about, etc...  Cabin will be four season use, heated and cooled with an 18K BTU mini split supplemented by a wood stove.  Water and power will come from the main structure and waste will be tied into the existing septic system. 

I was initially thinking of building it exclusively from locust from my property but am leaning away from that just due to the logistics of taking down the amount of trees needed at once, etc...  I had a thought recently about buying wholesale logs and building a log cabin, which is not entirely unexpected since I grew up in one:





That's me on the floor at about four years old with my dad in the background-he and his cousin did most of the work.  My parents bought a kit through Lincoln Logs out of Lake George, NY and built that log Cape Cod about 35 years ago and are are still living there today.  They of course bought an entire kit complete with windows, doors, fixtures, etc...but I'm looking to put up a simple 16' x 20' box.  The catch is I need high walls in order to have a standup loft.  Any reason that I cannot stack 8x8 logs 12' high?  I would be using 8x12 locust beams from the property to support the loft and 8x10 locust rafters for the roof.  Here is a simple sketch:





I figure the process would be to anchor the first course of logs (with some kind of rot resistant sill underneath) to the concrete pad and begin stacking to build the 16' x 20' box.  At the the appropriate course the logs would be notched to accept the 8x12 locust loft beams, and then the stacking would resume to a height of 12'-0"  At that point the logs would be capped off with a locust 2x8 to provide a bearing surface for the 8x10 locust rafters.  The loft and ground floor flooring would be 5/4 locust boards.  Locust would be used wherever else it would be needed as trim, framing, etc...of which there will be minimal need.  Again, my biggest concern is building log walls this high-my parents' place only has log walls stacked to 8'-0" and then everything above is stick frame platform construction with log siding.  Thoughts?

Offline NathanS

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Re: 12' High Log Walls?
« Reply #1 on: October 21, 2021, 07:08:32 AM »
Don P is the one that may be able to best answer that question or offer guidance.

Down the road from me is "Loknlogs," which has sold log cabin kits for years. I also watched one go up this summer. I think they pressure treat the logs for rot resistance, they seem pretty nice.

My thought is that the corner joints where the logs overlap will be responsible for resisting most of the outward thrust of the rafters - and the logs in the middle of that 20' length are going to have a substantial amount of lateral pressure pushing them outward. You could probably calculate the horizontal thrust to test for deflection, or even failure, of an 8' x 8' beam. I would think fully scribed logs or properly placed lengths of rebar through the logs helps transfer some of that pressure to the floor diaphragm, but I don't know that much about log construction.

I think the trick would be to make the ridge a load bearing beam, so that the rafters have no outward thrust. Otherwise it seems like the logs would be fine. Considering you have the means to raise all those logs for the walls, setting a heavy ridge beam is something you may already be set up to do.

Sounds like a cool project.


Offline ─▒llosia

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Re: 12' High Log Walls?
« Reply #2 on: October 26, 2021, 12:31:32 PM »
I'm going to be constructing a 16' x 20' guest cabin/office on my property.  No construction code to worry about, etc...  Cabin will be four season use, heated and cooled with an 18K BTU mini split supplemented by a wood stove.  Water and power will come from the main structure and waste will be tied into the existing septic system. 

I was initially thinking of building it exclusively from locust from my property but am leaning away from that just due to the logistics of taking down the amount of trees needed at once, etc...  I had a thought recently about buying wholesale logs and building a log cabin, which is not entirely unexpected since I grew up in one:





That's me on the floor at about four years old with my dad in the background-he and his cousin did most of the work.  My parents bought a kit through Lincoln Logs out of Lake George, NY and built that log Cape Cod about 35 years ago and are are still living there today.  They of course bought an entire kit complete with windows, doors, fixtures, etc...but I'm looking to put up a simple 16' x 20' box.  The catch is I need high walls in order to have a standup loft.  Any reason that I cannot stack 8x8 logs 12' high?  I would be using 8x12 locust beams from the property to support the loft and 8x10 locust rafters for the roof.  Here is a simple sketch:





I figure the process would be to anchor the first course of logs (with some kind of rot resistant sill underneath) to the concrete pad and begin stacking to build the 16' x 20' box.  At the the appropriate course the logs would be notched to accept the 8x12 locust loft beams, and then the stacking would resume to a height of 12'-0"  At that point the logs would be capped off with a locust 2x8 to provide a bearing surface for the 8x10 locust rafters.  The loft and ground floor flooring would be 5/4 locust boards.  Locust would be used wherever else it would be needed as trim, framing, etc...of which there will be minimal need.  Again, my biggest concern is building log walls this high-my parents' place only has log walls stacked to 8'-0" and then everything above is stick frame platform construction with log siding.  Thoughts?

Hello there. A great guide. I'm grateful to you for this. Good luck with your efforts. I will definitely follow the sequel. :)

Offline JRR

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Re: 12' High Log Walls?
« Reply #3 on: October 30, 2021, 04:41:11 PM »
Would there be less bending in the wall section if the wall logs were vertical?