Overview
The Permanent Wood Foundation System is an engineered system that is thoroughly proven and approved for foundation and basement construction based on years of testing and field evaluation.
Originally known to builders as the All Weather Wood Foundation because it can be installed in wet or even freezing weather, the Permanent Wood Foundation is a significant advancement in foundation construction.
The Permanent Wood Foundation (PWF ) has been proven over three decades in hundreds of thousands of installations, demonstrating it to be durable, economical, environmentally safe and energy efficient. It is accepted by building codes and Federal Agencies and by lending, home warranty and fire insurance institutions.
The PWF is a below-grade load-bearing foundation wall framed with CCA treated lumber and sheathed with CCA treated plywood. CCA pressure treatment permanently protects the wood from decay and termites. Footings are crushed stone and are engineered to provide both structural support and groundwater drainage. Carpenters do all the work since no concrete is required.
Treatment is per code requirements for penetration, retention and drying after treatment. The required retention of preservative is .60 lbs. CCA per cubic foot of wood, which is 50 percent higher than codes require for many other ground contact applications. Fasteners are stainless steel.
Permanent Wood Foundations are engineered to withstand soil loads, wind loads and seismic stresses that can defeat other foundations. For example, during the 1997 floods in Fargo, North Dakota, PWF basements withstood inundation without structural damage, unlike some concrete block foundations. Plywood sheathing is well-known for its shear strength under wind and seismic loading.
Additionally, the PWF incorporates moisture control features that provide the warm, dry, livability of above-ground rooms--NOT the damp and musty feeling associated with concrete or masonry basements. PWF basement walls are insulated and finished just like any other room in the house without sacrificing floor space.
Using wood below ground is not a new idea. The long-term in-ground durability of properly treated wood has been proven over many decades by thousands of buildings and other structures supported on wood piles, each a striking example of the long-term performance of properly treated wood.
Complete design details for the PWF are available from the Southern Forest Products Association.
E-mail Hoover's Technical Service Department or request sales information.
