Permanent Wood Foundations- help!

[Rohan D.]

Hi BP folks, I came across an inspection report for a 25 year old house which was built on Permanent Wood Foundation. What are the things I should be cautious about this kind of foundation? (for eg: grading of the house outside, rot, exposure to moisture...)

I am worried about the long term expenses that come along with it?

What is the life of the foundation I should expect before it starts to cost me?

Lastly what is the worst case expenditure I can expect to fix the foundation.

Assuming it has NOT been maintained with the best care.

House is approx 1700 sq ft

Thank you!

[George W.]

I would make sure that all of the posts that form the foundation are pressure treated to prevent them from rot. I'd also check that the theres no where in the house with loose feeling floors. I'd be careful with what type of soil it is on. Certian soils dont do well with no footings. 

How deep is the crawl space? If it's just wood sitting on directly on the ground, that would be a lot harder to work/repair then a 3 foot deep crawl. On a deep crawl space you could get under and install concrete pilings much easier. 

I have a place that I'm working on right now with a wood foundation and its old. Nothing was pressure treated wherver termites could get in, they ate right up. A header that spanned a good part of the house totally rotted away due to termites and moisture. It is a lot harder fix because the depth of the crawl was 8". If it was 3-4 feet deep itd be much easier to fix than a crawl space 2' or less. 

Worst case scenario the house sags bad and you have to lift the house out of the way to build a new foundation and put it back on. In my case I had to cut out all of the floor joists, dig below the frost line install a footing, and new foundation. Was able to do without moving the house, but had to jack it up to catch the weight of the room luckily it was only one room that needed this work done. The rest of the house was an addition and had a real masonary foundation. I would've highly considered knocking it down and building new had the rest of the house been sitting on wood with such a small crawl space.