Permanent Wood Foundations are used in lieu of poured-in-place concrete or block foundations and are constructed with wood that has been pressure-treated with pesticides to preserve the life of the wood and prohibit rot and deterioration.
Those in favor of the Permanent Wood Foundations suggest that it is less costly to construct than the traditional wood foundation and that it makes the job of finishing a basement significantly easier and less costly by allowing plumbing pipes, electrical, and mechanical to run through the wood foundation.
As you noted in your letter, proponents also claim that dampness is greatly reduced due to the fact that the concrete or block foundation is porous where, on the other hand, a wood foundation can be insulated thereby minimizing condensation.
While all of this may be true, there are, in our estimation, some major drawbacks with the Permanent Wood Foundation. The first is life span. Assuming proper construction, protection and maintenance, a concrete or block foundation will far outlast a wood structure. Although, concrete is susceptible to movement and occasional cracking via hydrostatic pressure, it is not nearly as vulnerable to damage due to water and other structural pests as is wood. Even pressure-treated wood will deteriorate in time and with prolonged exposure to dampness.
Some environmental groups also have trouble with the Permanent Wood Foundations. They fear that the wood-preserving pesticides contained in this material will leach into the soil and hence the groundwater system, tainting both and resulting in potentially serious health hazards.
Where dampness is a problem, a properly installed, waterproofed and ventilated concrete or block foundation will provide the greatest level of ongoing protection. Whereas a wood foundation makes finishing the interior of a basement a bit easier, the same condition can be achieved by installing a 2"x4" stud wall in front of the interior face of the concrete or block foundation.
This stud wall will make the space easier to finish by allowing you to run electrical and plumbing in the wall. It will also make the space more comfortable by providing a cavity for the installation of some insulation.
While it's true that for finished basements the stud wall is added expense, we believe that the drawbacks associated with a Permanent Wood Foundation make the traditional concrete or block the preferred choice. Spend the extra $1,000 now, rather than several thousand in repairs later. Remember, a home is only as good as the foundation that it rests upon.