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Permanent wood foundations


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I inspected my first permanent wood foundation (PWF) last year. I had read about them in the past. The one I inspected had a traditional concrete footing, it was in good shape and I found no problems other some damaged masonry coating at exterior perimeter. Some types of permanent wood foundations have a rubble/gravel trench footing. This type will have treated stud frame stem walls resting directly on rubble trench footing. The main things to look for are rot and any displacement of perimeter walls. Google "Permanent Wood Foundations" for some more info.

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I found and read the American Wood Council design manual. It basically confirmed my suspicions/experience. The 6 mil poly waterproofing won't survive the gravel backfill, the caulked plywood seams won't be waterproof for more than a few years, and since I can count the number of PWFs in my area on one hand it is highly unlikely the wood treatment is graded for PWF use.

The inspection is on hold for now. The clients went to view it again last night and there was a geyser in the basement. She really loves the above grade portion of the house, He is shopping for a new foundation. If the repairs are less than the concessions so far it will likely still go.

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Tom,

You can download a free Permanent Wood Foundation Design and Construction guide from the Southern Pine Association's website. Click the hot link. It will take you to the Southern Pine Publications Page. Scroll down to the bottom of the right column of pubs where find the link for the guide. Click the link and a box will pop up asking for a user name and password. Click the 'create an account' button and then sign up to access their pubs. When you finish filling out the form and click proceed it will download that document straight to your downloads cache.

I downloaded my first copy of that document over a decade ago and just updated to the new copy.

ONE TEAM - ONE FIGHT!!!

Mike

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I would imagine we have inspected a thousand or more over the years. for the first couple of decades 1976-1995 most were poorly done and a quick and cheap alternative to concrete. Remember, we see crawl spaces one or two times per year.

Now there are entire subdivisions with wood foundations. They remain less costly, but still have a certain stigma to potential buyers. Mostly there are well done now and have an advantage of being more energy efficient and easy for a homeowner to finish. I have seen only two failures (poor workmanship) on the ones built since abt 1995.

Builders now have better barrier materials for exterior walls and understand it is all about moisture control; sumps, pea stone, perf pipe, etc.

Still, I can't recommend the system unless concrete is not available.

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ICC documents and prescribes very well in this category...but their material is copyrighted...there are ways to get such docs online posted by those among us who think that, if documents are to be adopted as laws, then they should be available without charge...without posting url just google seal of approval, you should be able to find your way to prescriptive resources without charge...

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ICC documents and prescribes very well in this category...but their material is copyrighted...there are ways to get such docs online posted by those among us who think that, if documents are to be adopted as laws, then they should be available without charge...without posting url just google seal of approval, you should be able to find your way to prescriptive resources without charge...

The ICC has an online library that anyone can use. It's just awkward to click on one section at a time.

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