April 26, 2011 | A concerned homeowner in British Columbia asks:
I have a 3-foot crawlspace which has a damp concrete floor whenever we get heavy rain. Consequently, the exterior pony walls carrying the fiberglass insulation are beginning to decay. Can I replace the pony walls with preserved wood and not put a finish cladding on it? Is there a toxicity factor here if the wall is not properly sealed? Timing and budget are not big factors here as much as having the job done right. Thank you.
Huck DeVenzio of Arch Wood Protection Reponds:
If you purchase properly treated wood (we, of course, recommend the Wolmanized brand) intended for ground contact, you can be confident that the wood will resist fungal decay for many decades, and you don’t have to be concerned with sealing or cladding. Treated wood has been used for years in Permanent Wood Foundations (made of treated studs and treated plywood), framing for all homes in Hawaii (where termites necessitate this), and for the sill plate of nearly all homes in North America. In all of those applications, many left unfinished, there is not a single known adverse health or environmental incident from the preservative in the wood.
Because of the dampness and your past problem, I would try to get wood treated for ground contact, even if most of the lumber will be above ground. That gives you an extra measure of security.
You can probably find properly treated wood at a lumber dealer near you. I hope this helps.