Preserved Wood

Preserved Wood Foundations

Preserved wood foundations, also called permanent wood foundations, are constructed with pressure treated wood framing and pressure treated plywood cladding. The cavity between the framing members is insulated and drywall is generally applied to inside surface. The floor can be constructed of preserved wood or concrete. This is the same pressure treating process that is used for decking and fences.

Popular Choice in Modern Homes

PWF have been gaining popularity over the last 50 years. Some of the benefits claimed for Preserved Wood Foundations include:

  • Easy to build
  • Easy to finish
  • Easy to modify in order to add more rooms or change the shape in the future
  • Structurally strong
  • Long lasting
  • Resistant to insect and rodent damage
  • Ideal for the do-it-yourselfer

However like all other foundation types, PWFs are not maintenance free and problems can arise from time to time.

Problems with Permanent Wood Foundations (PWF)

1. Water Penetration/Waterproofing

The solution to waterproofing a PWF lies in the way it is shielded and the DELTA-MS waterproofing membrane system provides two lines of defense. The first is an impermeable plastic sheet that is waterproof. The second is the dimpled structure that offers a free drainage path. In the event that water passes the first line of defense, it can flow freely down the air gap to the footer drain. Unlike a coating, DELTA-MS bridges all size cracks, ignores damage points and deflects water as well as soil dampness. It also allows for the drainage of construction moisture to the footer drain.

2. Weeping Tile

All building codes require a perimeter drain system regardless of the type of foundation. Root obstructions may be able to be removed using a sewer machine but this also is a temporary fix. Trees need water and the weeping tile around your house is an excellent source. There are really two options, replace the weeping tile or abandon the weeping tile. We call the process of replacing the perimeter drain tile an Exterior Excavation which as its name implies, is done from the outside. Abandoning the tile does not mean ignoring it and letting it leak, or filling in the basement with concrete.

Preserved Wood History

The early 1960s saw much research into the feasibility of using wood for foundations. It was not until the mid-1970s that the concept gained widespread acceptance. In the 40 or so years since then, hundreds of thousands of houses have been built on preserved wood foundations.

3. Window Wells

Any time a window is located below grade, a well of some sort is required. A window well is a shaped piece of corrugated galvanized steel that protects your basement from leaks. 

A basic galvanized well may seem like a simple item with simple installation. If that were true, fixing window wells would not feature so prominently in our business. Improper sizing, placement, installation, and drain structure are just some of the problems we remedy on a regular basis. Visit our Window Well section for more information.

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