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Why good log homes don't settle
Okay, we admit that there is such a thing as settling in log homes. The catch is that it only occurs in log homes that were built the wrong way, in our opinion. If you build a log home using the butt-and-pass method, and you build it correctly, there is no settling to be concerned with.
The Truth about settling
The problem is that kit log cabin builders need some reason to exist. If everyone knew about the butt-and-pass method of log home construction, there would be no more log home kit dealers. Why? Because you can't make a "kit" out of a butt-and-pass log home. It simply is not possible -- a butt-and-pass log home is so strong (when built correctly) that you can't build it in a factory then take it apart and ship it somewhere else to reassemble it. It can't be done.
So the kit builders choose the next best thing: building a type of log home that does come apart in their factory, and then they ship it to John and Martha's property and reassemble it.
What's so bad about that? Settling occurs in any type of log structure that has the ability to come apart, such as Scandinavian Chinkless, Canadian Chinkless and Saddle-notch log homes.
So after the kit builder reassembles John and Martha's new kit home, everything is wonderful. And about a year later when the logs have finished drying, the settling is noticeable. Maybe the stairs are out of alignment. Maybe there is a gap between the log wall and the roof. Maybe a window has shattered from the weight of the logs above it.
These are some of the reasons that "kit" log home builders cut keyways and "settling space" above each window and door. So when the logs shrink and settle, they won't crush the window or door. We've even seen log home kits assembled with a giant screw jack in the basement that allows the homeowner to "lower the roof" over time as the house settles.
The good news is that you can avoid this nightmare and the extra expenses associated with it. All you have to do is build a log home that doesn't come apart and doesn't settle like a bag of potato chips that someone has sat on. In other words, consider building a butt-and-pass log home, and consider building it correctly.
Kiln-drying vs. air-drying logs
Seasoning your logs is important when you are building a kit home, because of the settling issue. The more moisture that is in your logs when you build the house, the more settling will occur when the moisture finally gets out.
However, seasoning logs the right way costs a lot of money, especially for a large kit home manufacturer. To do it properly the logs must be out of the sun and rotated the proper way for a year. And they shouldn't be stacked up, they should be spread out evenly on the seasoning rack. So for a kit manufacturer to do this they would practically have to build an airplane hangar to store their timber for the next season. (We don't know about you, but we've never driven past a kit manufacturer on the highway and saw an airplane hangar filled with logs).
So the various kit manufacturers cheat somewhat by coming up with less expensive and faster methods of seasoning the logs that go into their kits. Most of these methods involve drying the logs in a giant kiln or blowing them with hot air in some fashion to accelerate the process. In fact, manufacturers are generally out there advertising what great methods they have for drying their logs in an accelerated fashion. It's a selling point that their logs are kiln dried or baked in an oven because it sounds high-tech and exciting. The average log home kit buyer has no idea even why the logs are supposed to be seasoned before they go into a kit.
The problem is that when you accelerate the process of drying logs, they tend to lose moisture on the outer layers of the log but retain it on the inside of the log. Seasoning a log properly takes months because moisture in the center of the log dries out very slowly.
So here's the million-dollar question: if kiln drying logs is so great, why do they still put keyways and "settling space" over the windows? The answer is because the logs still shrink and settle. Even if you season the logs properly for a year and build a kit-style home, you will still need to expect some settling (partly because the home will be heated and this will reduce the moisture content of the logs further).
Now for the good news: with a properly-constructed butt-and-pass home, you don't need to season the logs. You don't need to bake them in an oven or kiln. You don't need to stack them on a seasoning rack for even a day.
Because a correctly built butt-and-pass log home doesn't settle the way kit-style homes do, you don't need to worry about the shrinkage of the logs or their moisture content. You don't need to jump through all sorts of hoops (such as keyways, settling space, screw jacks, etc) to build a beautiful, exceptionally strong, exceptionally inexpensive log home.
Comments
Shrinkage of logs
It must be me but i do not understand why Butt and Pass built home do not settle.
I understand that it is the way thay are built but as I do not now how the butt and pass home is built I am still at a loss.
I do understand how a kit home could settle with the way it is designed but how is it the Butt and Pass home has no settleing? Or is it as simple as the :- The Putt and Pass home will settle but by so little you need not worry if you build it correctly?
David
Why Butt and Pass buildings don't settle
To Dave:
For an answer to your question, check out the article on Log Homes in Wikipedia under item 5 Structural Types of Log Homes.
Hope that helps.
Paul
Direct link
Good summation on Wikipedia. Here's the direct link:
http://en.wikipedia.org/wiki/Log_home#Structural_types_of_log_homes
Settling
Perhaps I missed something, but I didn't see anything in the Wikipaedia article that suggested "Butt & Pass" construction did not have settling problems. Quite the opposite in fact; after all "green" logs are being used and inevitably they will shrink. However there is a nagging thought in my mind that I once read a rational explanation on this site why B & P construction did not suffer from shrinkage problems; or that by reason of the construction technique shrinkage was accommodated
butt n pass construction
Well this method (LHBA B N P) does not notch out logs-therfore the logs although stacked on top of each other uses the shrinking onto the driven rebar to not settle down on log below-the logs shrink to their center --so WHEN they shrink THEY shrink away from each other and tighten on the pins, in our class taught method being rebar. This method of tight pinned construction should not be used on settling log homes or notched style logs where the builder MUST plan and figure for the settling. This fact was mentioned by the loghomeguy on this site.
edit: from loghomeguy http://www.loghomebuilders.org/drilling-logs
Ron
SETTLING
You need to be concerned about settling, not with the butt n pass logs, but the foundation. Be sure you build or have built piers or walls to the spec's suggested by LHBA. And whatever you do make sure the soil is virgin where you're laying your foundation (or you will need an engineer). It's not a bad idea to have the soil tested for compression if in doubt. When building with logs you are dealing with a lot of weight and the soil needs to be up to the challenge.
Odds are you'll be ok if you follow the program, however, it doesn't hurt to be on the safe side. Soil prep should never be overlooked!!!.................... :-)
Wikipedia article has been updated
The Wikipedia article has been updated, and it no longer includes an explanation of the tight-pinned method. Most likely because some unbelievers came along and removed it ;-)
Here's a link to the old article:
http://en.wikipedia.org/w/index.php?title=Log_home&oldid=268141006#Structural_types_of_log_homes
And in case that ever stops working, here's the quote of the entire "structural types of log homes" portion. What you are interested in is the second bullet point.
Structural types of log homes
From a structural perspective there are two fundamentally different types of log homes. In the most common type, the load forces of the building are transmitted to the foundation through the wooden logs. In the second type, the load forces are transmitted to the foundation through steel columns. These two types will be referred to as "Chinkless" and "Tight-pinned" respectively.
* Chinkless homes may have some chinking or sealant between the log courses, but the logs are typically milled or scribed to fit closely enough together so as to minimize the chinking requirement. Since the logs bear the weight of the building, any shrinkage of the logs is cumulative and the shrinkage results in the settling of the building, that is, the vertical dimensions of the building shrink as the logs shrink.
* Tight-pinned homes typically are built with unmilled logs, and as a result, there are large gaps between the log courses which must be filled with some kind of chinking material. The log courses are fastened to each other in pairs by steel pins which are driven through the logs. These pins are tight enough, and spaced closely enough (typically every 20 inches), so that they bear the entire weight of the building. The pins are typically 1/2 inch in diameter and are commonly made of rebar. When the logs shrink, each one shrinks around its own center line with the center line remaining fixed in its position in the building. As a result, the geometry and the dimensions of the building are unaffected, but the gaps between the log courses widen. Typically, the logs end up not touching each other so they play no part in the transmission of load forces. The logs do, however, prevent the pins from buckling under the load for the portion of the pin inside the log. The portion of the pin in the gap between the logs is a short column and thus is able to withstand the load without buckling.
* Advantages of the Chinkless method:
Once fabricated and assembled, the shell of the log home can be disassembled and the parts shipped to the final building site. This allows for centralized manufacturing of the home and relatively quick construction at the final site.
* Disadvantages of the Chinkless method:
Special consideration must be given for the settling of the building. This includes such things as slip joints over all the window and door openings, jacks under any vertical element such as columns and staircases which must periodically be adjusted as the building settles, allowances in plumbing, wiring, and ducting runs, and fasteners for the walls themselves to prevent uplift.
* Advantages of the Tight-Pinned method:
No allowance for shrinkage need be considered or made, thus simplifying design, construction, and maintenance.
The building is claimed to be stronger than the Chinkless buildings. However some disagree [1]
* Disadvantages of the Tight-Pinned method:
The building must be fabricated and assembled on the final building site.
Chinking maintenance is higher than for the Chinkless buildings during the period of major log shrinkage. That period may be several years for green logs.
Typically, the Chinkless method is preferred by log home manufacturers and the Tight-Pinned method is preferred by many do-it-yourselfers who build their own homes. Individual log home builders who do the work on the building site will find either method suitable for their purposes.
RobertWoodChambers got rid of the bit on tight-pinned log homes
On February 20, 2009. Here's the diff:
http://en.wikipedia.org/w/index.php?title=Log_home&diff=271975248&oldid=271975055
His reasoning was "Wikipedia objected to all how-to content in this section."
Not sure how it qualifies as "how-to content" but hey, I'm no editor. I just build log structures ;-)
wikipedia
Ragdump
You can register at wikipedia then you can write your own artcale and post it there if you want
You'd have to source it,
You'd have to source it, though--if you just make a claim and don't put a source for where you found that out, it will likely get deleted--especially if it's something like this where some people might be contentious about it.