Permanent Wood Foundations are a real option, code approved literally everywhere and offer many advantages to a "green building" project. In addition to being low cost. They offer significantly lower "embodied" energy than concrete weather it's in ICF or not. There are likely more PWFs (several million in the US) in existence than ICF foundations. The concrete industry and foam industry Perpetuate much dishonest criticism of PWF, blatant lies like "all wood will rot", PWF won't outlast a mortgage etc. There are no cracked PWF foundations even those over 60 years old. NONE have " failed" or had to be totally replaced. The simple fact is PWF is actually likely to endure the stress of time better than concrete or foam and has only one identified degradation mechanism, the corrosion of the fasteners, which only have a 10% failure probability in 500 years. Proper design and construction are not like concrete and "beginners" often make consequential mistakes a forum here would be helpful in avoiding the mistakes.

Posted By Liebler on 12 Nov 2017 07:15 PM
Permanent Wood Foundations are a real option, code approved literally everywhere and offer many advantages to a "green building" project. In addition to being low cost. They offer significantly lower "embodied" energy than concrete weather it's in ICF or not. There are likely more PWFs (several million in the US) in existence than ICF foundations. The concrete industry and foam industry Perpetuate much dishonest criticism of PWF, blatant lies like "all wood will rot", PWF won't outlast a mortgage etc. There are no cracked PWF foundations even those over 60 years old. NONE have " failed" or had to be totally replaced. The simple fact is PWF is actually likely to endure the stress of time better than concrete or foam and has only one identified degradation mechanism, the corrosion of the fasteners, which only have a 10% failure probability in 500 years. Proper design and construction are not like concrete and "beginners" often make consequential mistakes a forum here would be helpful in avoiding the mistakes.

Liebler,
I sold wood foundations in NW Pa and Western NY during the late 70's and a simple web search will reveal many PWF failures , especially where the soils are wet.

Chris, Please provide a few links to failed PWFs that were properly installed. All I've been able to find are repairable modest damage due to clearly shoddy installation. Nothing even approaching the disaster of failing concrete due to aggregate issues in Connecticut. Silence confirms there are NONE!

"Where soils are wet"? Like you sold PWF and put them in swamps? I'm most certain the soil gets wet in my state for all foundations, the rain in WI doesn't discriminate.

You shouldn't be dropping basements in a high water table and you shouldnt backfill with poor draining soils. Nothing wrong with PWF, there's documented failures of every technique and its pretty obvious the what the common theme is across the board. If someone wanted to, you could create a wet, damp basement made out of anything.

That said Liebler, Im guessing you'd get maybe 3 comments a year, its always going to be fringe. Im with you though, we have a couple in the family, one circa 2002 and one from early eighties and they're great. I wonder about the preservatives in the eighties one, maybe both. Cant remember when/if they changed foundation grade preservative.

Greentree,
Why do you say PWF will always be "fringe"? There are several million in the US and a similar number in Canada. Pwf is substantially "greener" than concrete being made of mostly renewable wood and using a minimum of highly polluting and very energy intensive concrete. Proper design and installation are, no doubt, more important than with concrete but the results are simply better. A forum here could help avoid the mistakes of shoddy practices.

It doesnt have any real market penetration, of a million new home starts, how many are on a PWF? Very, very few, would you say less than half a percent or worse, and its been around a long time. The traffic on the SIP and ICF boards is basically dead and they are way more mainstream, Im not saying its not green, although I would be leary of all that preservative inside the conditioned space if it were my home. Im saying the numbers arent there to make it active.

Greentree,
You are no doubt correct that PWF is not mainstream, at least not outside the Midwest. Why is a darn good question. Lack of knowledge is part of an answer. Serious disinformation by the vested interests promoting foam and concrete is part of an answer. Builder inertia, not doing anything different than we've always done it, is probably the biggest issue. All of these would be changed if the home buying public were aware of the significant cost, energy use, and other benefits offered by properly done PWF foundations and basements. A forum here could help create such awareness. IMO neither ICF or SIP have any place in green building. ICF is not in any way a "green" technology but a combination of two highly polluting energy wasting technologies, petro based foam and concrete created by burning coal. SIPs reliance on petroleum based foam makes it less green than more conventional wood frame cellulose insulated structures FWIW In my PWF basement, the only preservative in conditioned space is the PT bottom plates of walls sitting on the basement slab which would be there even if the basement were a concrete tub.

One of the reasons I didnt do a PWF was because of the limiting height in the design guide that I had at 8', have they increased allowable height to get a 9' wall without requiring an engineer?

Greentree,
Anyone can be the engineer! All they have to do is to follow the design specification and go through all the steps. There is a "prescriptive" design that requires no engineering by anyone but as you observed it doesn't allow a fully buried basement with 8' ceiling height. I have done such a design, my walls are 9'6 1/4" and my back fill max is 9'. The soil pressure of higher back fill puts a lot of shear stress on the floor diaphragm so to get 9' back fill my floor I joists are aligned with the PWF studs with the sub floor over the upper plate of the PWF walls and the sub floor is a fully blocked diaphragm with screws (equivalent to 10d nails) on 3" centers around all sheet edges. Also the studs in my PWF walls are doubled 2x8's on 16" centers on the high back fill side. I also needed 2 interior shear walls in my basement due to the "walkout" and size (64'x40'). There is also a low cost ($400) design service available.

I haven't seen a PWF foundation in Ontario since the late 80's, and it was an experiment and the builder said never again, not sure why, I didn't have any background back then in this stuff. The prairies seem to use them quit a bit, but I also noticed concrete was very expensive out there, about double or more of Ontario so I can see why from a cost stand point.

I do not agree with any wood construction, material is organic, too unstable, life span is short, and if you use PWF, the chemical content can't be good for either your health or the environment. Wood is great for forming and temporary bracing, not a permanent structure