I have a question about PWF (wood foundations). My house is 10 years old, built on a PWF, and the soil is very sandy and tends to stay pretty dry, I have never seen any water in my sump pump pit. When we moved in 1.5 years ago, there was already insulation installed between the 2x8 studs and the insulation is wrapped in a vapor barrier and is stapled to the studs. My concern is that any moisture that might be behind the insulation would probably stay there and maybe cause moisture problems. I am planning on finishing off the basement with drywall and am wondering if we are able to simply hang the drywall on the studs as things are right now or if it might be a good idea to install something called 'proper vent' behind the insulation which would create a gap between the treated plywood wall and the insulation and have that gap run from the floor to the top plate of the framed wall and then out over the top of the insulation/drywall to allow any potential moisture coming through the wall to escape out into the basement. Would installing this 'proper vent' be useful to provide added protection from the foundation developing moisture problems over time? Or would it be a waste of time/money considering that the soil doesn't retain much moisture and there should be a vapor barrier on the outside of the foundation which should prevent moisture from coming through the wall anyway? I just don't want to finish the basement and have moisture problems down the road if I can take steps now to help prevent that. Thanks.

[Brian A. MacNeish]

I've worked on and built a few PWF's. If the PWF was built properly (proper caulking at plywood joints, proper grade), strong, thick exterior moisture barrier, and soils as described, you should have no problems. One of the first PWF's in my old home area is now 33 years old.

The last new house PWF I built is now 23 years old, built alongside a lake that creates a high water table (about 1-1.5' under the basement floor). It has had no problems due to the PWF. The area had some problems when an excavation contractor built a house next to the PWF. He changed local grading, creating water problems for a couple of concrete foundations also as well as killing a few mature trees due high water levels over the roots!!

Got any pictures you can send?

Not sure how to send pictures on this site, what exactly would you want to see? As for my interest in this subject, the basement right now seems to have low humidity, but I'm not sure how much of that is due to the walls not being completely finished off. I'm afraid that once I cover the walls with drywall that it will essentially trap any moisture coming through the outside wall inside the wall and maybe weaken the foundation over time and we might not even be aware of it because we can't see it. Do most of the PWF's you built have finished basements? As for how good of a job the builders of my PWF did, I don't know, we moved in about 9 years after it was built. I would imagine there is a code that the builders would need to follow in order to even build the PWF right? Would that require them to do everything you mentioned in your reply? Would it be a worthwhile investment of time/money to try to install the proper vent in behind the insulation just in case there might be some moisture coming through?

[Brian A. MacNeish]

Where are you located? Send me a private Email with your Phone number if you're in the Canada or the US. I then can call for free to help you.

I'm located in Central Wisconsin. Email: RNEGR274@AOL.COM Phone: 715-343-1544
Thanks.