I inspected a PWF house today. I’ve worked on homes with them but this is the first time I inspected a PWF. Check out that floor system. Built in 1981.
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I have yet to encounter one. Were those sidewalls wet?
Walter, I have inspected many floor systems like that and, from what I can see, it is fine.
Happy inspecting.
It looks like pt plywood, as it should be, IMHO.
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Same as Larry indicated, looks fine.
I inspect half a dozen a year and have yet to find any issues. About half of those are finished basements with only a small area in a mechanical roof to actually see the interior side.
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That is pretty impressive for a 40 year old home. I have seen a lot of CMU block not perform so well.
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No they were dry. I probed every other bay on the entire perimeter.
I agree Larry just sharing.
When I was in my early 20’s. We built these with full basement walls in southwestern Minnesota. At the time I always thought why would someone want this instead of a concrete foundation and wondered how long they would hold up. Thanks for sharing.
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I’ve only done one and it had failed in a major way. My understanding is that they have to be constructed in a manner that does not allow the builder to stray at all from the designer’s instructions and will not work in places where they will be exposed to much groundwater or seepage.
Proper inspection involves probing the plywood around the entire foundation. In my mind, building the underground portion of a foundation out of wood is lunacy, and I think of them as “Powdered” Wood Foundations.
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Are the wall studs secured to the footing plate? I don’t see any type of mending plate or fastener. I can’t imagine the studs are just sitting on the footer…
I’ve tried searching on how to build a PWF, but can’t really find much info relevant to my question.
There’s not a lot…Perm Wood Foundation.pdf (2.1 MB)
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Kenton … When it comes to probing the exterior sheathing, with what and how deep down is recommended? Thanx
From Kentons link, the slab detail of figures 17 and 18; and the connection details of figures 20, 21, and 22 are the critical components. In addition, figure 21 shows the blocking detail, and that blocking often runs 3 or 4 more joist spaces towards the interior (not shown). The structural details between the floor framing and foundation wall are critical for deep buried foundation walls and often are missing in amateur builds.
I have been involved with a number of engineered wood foundations during my construction career. The issue is inexperienced homeowner builders and even inexperienced builders. I’ve inspected about a dozen now and have seen some major structural failures. I’ve also inspected well built wood foundation systems. Built right, they are good.
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I’ve only seen one fail, and that was when I was purchasing a house. *didn’t buy it. otherwise I have never stumbled across one when inspecting. *granted I don’t have to many under my belt.
Here is a decent video and article from structure tech. :
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