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Non-Settling Log Homes
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Replies to This Discussion
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Permalink Reply by Bob Warren on -
EZMARY,
You are right about that. At the ICC meeting 5 or 6 years ago the issue of settling and "non-settling" was one of the larger debates. The big one was the definition of a log.
In the end it was looked at that a "non-settling" system would have no more settling than a conventional framed house.
So, there are lots of things you must do (according to ICC) to accommodate settling. But in section 304.3 it gives the exception. Basically if a log wall settles less than 0.5% to a maximum of 1/2" then it is considered non-settling.
If you have a 100" tall wall and it is figured to settle .5% that is 1/2" and you are okay, by the definition it is non-settling. However if that is a 2 story house it will be above 1/2" and the provisions for settling allowances would apply to things such as chimneys and plumbing vent stacks. They would not apply to doors and windows no matter which floor because the involved settling height is small and the settling though those openings would be less than 1/2".
Clear as mud eh?
Bob Warren
Khita Log Builders Ltd.
member of the ICC log Structures committee and more
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Permalink Reply by PETER KLOSE on -
Correct, non setting for log homes does not exist. We build log homes produced in Finland and we calculate an average of 1 cm setting per meter building height. So a 3m high wall will set with 3cm. All this depends on the humidity of the wood during the production and storage. Also the humidity of the air at the building side is important. However, the setting has no impact on the house structure if you build with the appropriate techniques. We install all passive elements as doors, windows in a sliding frame construction. All non stetting elements have to be installed in such a way that the setting walls can move around it. Sounds complicated but is not so difficult.
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Permalink Reply by David Fanning on -
I have built a 30 by 30 tightly pinned butt and pass log home with real logs that has not settled.
I stacked my logs in 2007 and stuck in the windows a year later.
Before bob goes nuts, The logs do shrink around their centers but the height of the wall remains the same... So my windows and doors continue to work just fine... The LHBA has a way for low skilled individuals can stack logs with out the difficult design problems of settling... Its easy...
check out my photobucket site...
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Permalink Reply by Rick Taron on -
Thanks for sharing that Dave. Were your logs cut in the winter and seasoned for a bit? How long? You guys did a nice job for not having any experience with logs.
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Permalink Reply by David Fanning on
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Logs were cut in Jan and Feb. 2007 peeled by hand by early May, air dried, treated twice with Boric Acid, and turned, then stacked in 12 days (with 3 individuals, well actually 2 1/2) with a boom truck in late July.
I actually have a 10 minute video that shows much of the entire process... I have shown it to some of my students ( I sub. teach in Hawaii) because they don't have a clue where lumber comes from nor how it is made...
About my doors and windows, you must understand my son Allen (shown cutting the windows) did not leave the normal 1/2 inch slop that is taken up in stick frame house with shims and stuff... Most of the window opening had 1/4 in or less between the bucks and the windows... There was no allowance for shrinking logs... because there is no shrinkage...
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Permalink Reply by Rick Taron on
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I did see that video, nice music!
So, in the log world we would call them, green logs.
And there would be a lot of shrinkage going on after you stacked the walls.
I see you have supported the ridge on the inside with a column from the main floor. And I think you bolt the log wall to that column. Is that right? So the ridge won't come down, and you are trying to hold the walls from coming down with the tight pins and the column. right?
what was the spacing of the pins? it looks like you used 1/2" rebar?
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Permalink Reply by David Fanning on
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There is shrinkage around the center of the log--- but no settling at all. If there was settling, even a little bit, my doors and windows would be breaking or not working at all..I know what bob thinks, but I try to ignore his negative stuff...all I can do is just smile and open my doors and windows. :-)
Actually several discussions were related about Skip and the ridge pole. Because the way we pin the rafters, several believe the ridge pole unnecessary to hold the roof. The rafters are pinned to the top log and to the ridge pole. My rafters are 4 by 10's
I have built a 30 by 30 and I have over 900 2 foot pins holding everything together. In fact there is so much steel in my log home, my son must go outside in order to use his cell phone... I also have a bunch of 1/2 inch ( as well as three 3 foot pieces of 1 inch) all thread. Pinning and their distance is LHBA info that I do not discuss... But you can do the math and derive almost anything...
I believe you can run a tank into my log home and the tank will loose.
Here are more log homes that don't shrink... one of which is about two miles away ...
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Permalink Reply by Joe on -
David,
Not sure what happens with log homes to meet hurricane codes down here in Florida and along the Eastern shores but there are some strict rules for normal contruction. The ridge pole or column is required to anchor the roof and first floor (we don't have basements) so that the roof doesn't lift in tornados or hurricanes. The rafters have to be steel strapped to the side walls as nailing alone is not acceptable. The roof has to be nailed down about every 8 inches. The walls have to be "J" bolted to the foundation on the first floor and second floor. I suspect the common practice of using studwalls on top of the first floor made of logs would require anchoring of some sort.
To get wind insurance deductions older homes must be retrofitted with roof strapping. The newer code calls for 145 MPH winds and as we know hurricanes have visited many of the northern states while tornados have hit the midwest. The roof lifting off is the number one thing that we have seen after the hurricane has passed.
The block foundation walls have to contain rebar about every 4 foot. This is strictly enforced as well as the other codes.
Joe
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Permalink Reply by David Fanning on
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Joe...
Starting at the bottom...
My footer is exactly the same as the footer for a stone house in Washington. I even added and extra run of steel just for drill.
My foundation is 8 inches of concrete with vertical rebar every 16 inches and horizontal rebar every 16 inches with two rebar around every door and window opening, and other stuff
The foundation has rebar sticking up (about 30 inches) so the first layer of logs is firmly attached to the foundation. Then the next log is firmly attached to the log underneath, and so on...
I believe my roof more than firmly attached , but I believe that some engineers have added clips. I find much of the code that are focused on stick frame home are just ridiculous when applied to a log home...
For example, I needed to add a deck to my front door. In the 2009 code they are concerned that the ledger board at is attached to the home can break when torsional loads are applied. When I showed that I attach my ledger boards with 2 10 inch lag screws every 2 feet... all concern went away...I have over 170 feet of ledger boards in my home.
But on the other hand, log homes need to have plenty of overhang, hence this also increases the moment arm for those 145 MPH winds...
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Permalink Reply by Bob Warren on
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Actually there is shrinking. Don't confuse shrinking with settling. They are different. I had considered mentioning the Skip Ellsworth/ LHBA method way back near the start of this thread but didn't because I consider it to be such a poor way to build.
I wonder if you took exact height measurements after the logs were completed? If so and you checked again today I suspect that you will find about a 2% reduction in height. It makes sense. Green Douglas fir shrinks radially about 4% to oven dry. Given your location on the wet coast one could reasonably expect an equilibrium moisture content of about 15%. That being halfway between the fibre saturation point where shrinking begins and oven dry a 2% loss of diameter of the logs is to be expected and thus settling of about that amount.
Bob Warren
Khita Log Builders Ltd.
"more than just a two day course"
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Permalink Reply by PETER KLOSE on
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A nice build you did! Here some information concerning the setting of the log walls. As all horizontal installed logs have a setting due to air humidity there are ways to absorb these settings.
In Finland we have a system to install windows and doors in a Log wall in a particular way.
Sufficient space is needed above and below the window to absorb the setting!The window opening must be bigger then the window size. These openings need to be thermic sealings!
In the opening where f.e a window has to be installed we prepare a vertical groove of 3cm width and 5 cm depth over the whole height of the opening. In this opening we fit a T board that fills the opening.
The T side that faces into the window opening will hold the window frame. The Window with his frame may only be fixed by screws into the t board, not deeper. It may never be fixed trough the t board into the log wall. This would kill the sliding effect of the log wall around the opening.
Hope this is clear enough, when not, send me an email and I will mail you a technical drawing of it.
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Permalink Reply by Rick Taron on
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Does anyone out there have a Precision Craft home that is built to be a "non-settling" log wall system?
I see they advertise the Berry Houseseal method. Has anyone seen this? It doesn't look too stable to me. Each course is suspended by washers.
Also, Bob, it looks like it would require a lot of chinking too, as you pointed out. :)
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