I inspected a Permanent Wood Foundation today where the customary 6 mil polyethylene exterior moisture membrane was an ice and water shield type.

My first thought was that is better than poly but I would like a second opinion. The missing plywood strip at grade level was noted.


Never saw a wood foundation.
Have any shots showing the actual wood ?

If that 6 mil rips is the wood exposed and prone to rot ?

I think of them as Powdered Wood Foundations and disclaim them. Only seen two, both bad and I don’t trust them. Proper inspection requires probing through the ground around the foundation with a 6’ metal rod. My understanding is that they can last a while, maybe 30 years, if built correctly, but that’s a big IF and failure to build correctly turns one of the major structural components of a building to mush in not much time. They’re the Yugo of foundations in my opinion.

Same here with never having seen one in person but can’t imagine they would last long especially in the climate up there

Not too many around here either but they are cheaper to build than concrete and are more popular in remote areas.

If that 6 mil rips, the wood foundation is compromised and prone to rot. As we know even treated wood rot.

Some good info at link below, click on Publications, PWF Design & Construction Guide (you must provide an email address to gain access).

Good video Jeffrey, I’ll send the link to the client.


About 80% of the homes here have wood Foundations here. I have built hundreds myself. Poly on the exterior is not required as long as there is a moisture barrier of some sorts. We use a waterproof bitumen here. Tar all of the nails and joists first and then two to three coats of the bitumen. We do not use The grade level plywood strip as the engineers do not require it here. I know that PWF foundations get a bad wrap most of the time but I can honestly say I see more issues with concrete then PWF.

Thanks for the info Greg!

Only good location for a PWF is on the top of the hill. However if done correctly in the right location it will give less trouble than some concrete foundations.

Required by the engineer or not, missing grade level protection is always called out in my reports. It is (supposed to be) there for a reason! Whenever I see the protection is missing, 9 out of 10 times there is damage from lawn mowers and weed whackers!

Completely disagree with this statement. If built properly they are good in any location.
Have you Inspected many in your area?

I would be calling up every home I inspected if I called up the grade level protection. The parging is there to protect it. That is mandatory in our area as the UV light can break down the plywood fairly quickly.

Not as many as you but I have seen them sink crack lift on clay soil. Unfortunately here in SSM clay is everywhere. I would not use any PWF that might get wet for a period of time during flood season. Also Parging or Damp proofing is very minimum protection in my mind and will not stop water like a cement foundation will with proper draining and foundation dimpled protection.

Kenton is has let two PWF affect his opinion.
He needs re education.

That is all.

I have inspected a few in two different neighborhoods near Raleigh and they are in good shape after 25 plus years. The key is good drainage.


Micheal your comment does not make sense.

The last two comments I made make perfect sense.

Thanks for the info Gregg. I heard about PWF 35 years ago, believe it or not. But never seen one.
At the time it had already been proven to sustain for years to come.
Wish I could see one that was built way back.

Maybe Kevin will educate us further. :wink: