I’ve got lots of questions, here goes the first. I’m soon going to be building a 2000 ft2 house on the coast of B.C., Canada, just north of Seattle. I’m interested in preserved wood foundations. In a recent related thread, Nanny Gee gave a site: http://www.cs.arizona.edu/people/jcropper/desguide.htm/
that showed a diagram of a frost protected shallow foundation with preserved wood at the surface, much like a slab on grade set-up.I thought preserved wood foundations only existed with crawl spaces or full basements.
Can I build a slab on grade with preserved wood?
Replies
Usual reasons for PWF are (a) no access to ready mix concrete or aggregates for same, or (b) permafrost area. The BC coast climate rules out (b), and if you want to go slab then there goes (a). So why would you want to go with a PWF footing? With a mild wet climate you are certain to have problems in 30-40 years. If you are pouring slab then go with thickened slab edge. Most municipal areas at the coast have a 600 mm (2ft) frost line, so have the hole dug 2' deeper around the slab perimeter and then form slab edge accordingly. Pour as one unit.
Wally
sly karma Thanks for the reply, but are you saying that p.w. foundations do not hold up in mild wet weather? Everything I have read indicates the opposite. Thoughts anyone?
Mild wet conditions will break down any material faster and PWF is no exception. My point was that there doesn't seem to be a good reason to go this route from the conditions you've described so far.
Wally
Lignum est bonum.
Lots of good information here:
http://store.southernpine.com/images/ref400.pdf
johnnyd-- Thanks for that site on p.w. foundations. Lots of great info.