Pressure Treated Wood Basements

Hey guys, I’m drawing a blank…

In an unfinished PT wood basement does the PT wood need to be covered for any reason?


Is there insulation between the PT wall studs?

I would think you would want at least a vapor barrier in place. The exterior should have a 6 mil vapor barier per mfg. specs.

See the links for more info:

This may be of interest to those unfamiliar with PWF(permanent Wood Foundations)

HOME INSPECTION for PERMANENT WOOD FOUNDATIONS This is written for the Real Estate industry and those who may have an interest in appraising, mortgaging or selling structures that include a Permanent Wood Foundation (PWF). The PWF essentially is a wood stud wall sheathed with exterior grade plywood and engineered to withstand various foundation loads. It has been over 30 years since the first PWF’s were built in the United States in Lexington Park, Maryland and in Canada since 1961. Today there are hundreds of thousands of them if not more than a million. With this many wood foundation structures, more and more of them are being resold. Their popularity is increasing. It is therefore prudent that those involved in their resale become more familiar with their advantages and what makes them perform so admirably. What makes Permanent Wood Foundations attractive to home buyers? The one thing that stands out is how dry and comfortable the basement is. There are no musty odors and smells usually associated with the more conventional block wall and poured wall foundation basements. And, there is no liquid water or high relative humidity in PWF basements. The basement is just as comfortable as any room upstairs. This translates into more livable space. Since stud spaces are already available for insulation, and studs are already there for dry-wall or paneling; it is not necessary to lose more basement space with furring in order to insulate and finish the basement. This means a saving of area in the basement. It could amount to an increase in area of 25 to 50 square feet. For a ranch-style home, a PWF basement doubles the living area of the home without adding significant costs. An insulated wood foundation requires less energy to heat and cool. It can reduce heating costs by as much as 45%. PWF walls are generally thinner and are constructed of wood studs and plywood designed to resist soil and wind or seismic pressure; and support the weight of building above it and transfer the loads to the bearing soil. It is the bearing soil that supports all structures. Because the wood members of PWF’s are pressure treated with safe wood preservatives (CCA or ACQ) to retain 50% more preservative than would be used for a fence post or a deck, their useful life expectancy is easily predicted to be in excess of 120 years. Are the preservatives used for PWF’s toxic? Yes, but so is common table salt. The word “toxic” is a relative term. The amount of any chemical it would take to injure any human varies widely. The chemical that people seem to worry about the most is arsenic, and arsenic is a part of CCA preservative. It is in the form of arsenic pentoxide, and is locked into the cellular structure of the wood. Water will not dissolve it out. When we eat a seafood dinner (any shellfish), we will eat more arsenic pentoxide in one meal than we would eat if we ate a 2 x 6 by twelve foot long board. The splinters are more dangerous than the arsenic. Clams contain an average of 11.6 ppm of arsenic; table salt 2.7 ppm; and a dose from the arsenic in treated wood in not likely to exceed 5 ppm. It’s the dose that makes the poison. CCA pressure treated wood is safe. There is no taste and no emission of gases from the treated wood… There is no difference in home-owners insurance between wood foundation homes and conventional foundation homes. The original three wood foundation homes built in 1969 in Lexington Park, Maryland are continuously monitored by the National Association of Home Builders Research Foundation for horizontal and vertical wall movement, water leakage, humidity levels in the basement and for any evidence of decay, termite or rodent attack. To date we have heard of no problems of any kind with any of these three original PWF homes. Along with the original three PWF homes, a single concrete block home was also built by the same crews that built the PWF homes. This was done to compare costs fairly on an equal basis. It was found that the PWF homes cost 12% less than it cost to build the concrete block home. The average 1979-80 tax assessment on a 45% valuation basis was $23,543.33 for the PWF homes, and $23395.00 for the concrete block home. This is an indication that PWF homes continue to hold their value when conpared to concrete block homes. Roscoe Clark have over 21 Years experience building, designing and teaching the Permanent Wood Foundation System to Building Officials, Architects and Engineers, Builders, Lumber Dealers, and high school and college students. In Michigan we both are Certified Instructors under ACT 54 for Building Officials, Building Inspectors and Plan Reviewers. Warren designed and built the first wood foundation in Michigan, Indiana, New Jersey, and Roscoe designed and built the first wood foundation in Alabama. We have conducted PWF Courses are several Universities. We both are and have conducted Training Courses and Seminars all over the United States. Perhaps we can conduct a Seminar or Training Course for your group. Courses or Seminars are on all phases of the Permanent Wood Foundation System; from training builders on site, to teaching design, to teaching inspection, to teaching plan review, or to simply just give an overview of the system. Programs can be from One Hour to Two Weeks in length. They are tailored in subject and length to the audience. If you are interested in sponsoring such a training course or seminar, please get in touch with Roscoe from your lumer dealer.


In Canada the same rules apply in that it must be insulated to blow grade level. Other than that, no.