The Dome Store > Foundation Systems > Permanent Treated Wood Foundation

Permanent Treated Wood Foundation

Natural Spaces now offers pre-assembled foundation wall sections utilizing high quality ACQ pressure treated "FDN" (foundation) grade stamped stud and plate lumber. We design well above the minimum design specs stated in the American Plywood Assoc. PWF Design Manual. We offer ACQ-treated stud and plate lumber, which is considered to be environmentally safe. ACQ is an entirely different preservative process from CCA. Ask for our brochure on ACQ.

Our standard structural wall unit uses a 2X8 ACQ-treated stud spaced 12" or 16" o.c. The structural sheathing is 1/2", 5/8" or 3/4" ACQ- or CCA-treated plywood. Stainless steel nails are used throughout. Backfill boards, concrete slab screed boards and 2 X10 footing plates are included in our PWF system. Stuff the competition forgets to tell you. Steel brackets, braces, bolts, screws, etc., must be either triple zinc plated, painted with Rustoleum, or must be stainless steel.

Because of the custom nature of each dome and each site, we can only give an approximate cost. Specific quotations will be given when specific plans are produced and a specific site is selected.

Foundation Waterproofing

On any foundation, it is the waterproofing material that will keep it dry. We do not suggest the use of black tar - the real cheap stuff - as a waterproofing. It will dry out in 5-8 years, cracking, pealing, letting water seep into your foundation wall. Tar is only considered a damp proofing - it is not a water proofing material. 6 mil PVC will also dry out, become brittle with age and disintegrate. ANY portion of the 6 mil PVC exposed to sunlight will breakup within one year.

The premium long-term waterproofing recommended is the membrane system. The Grace Bituthene Waterproofing Membrane System is a self-adhesive, cold-applied sheet membrane consisting of a top surface of high strength, 4 mil polyethylene film laminated to 56 mils of rubberized asphalt. Rubberized asphalt promotes full adhesion to the substrate while simultaneously providing crack-bridging and crack-cycling properties. This 60 mil thick membrane is supplied in 36" wide rolls 75' long inter-wound with a disposable coated paper release sheet.

All corner wall joints in the permanent wood foundation walls receive an extra layer of the membrane. Strips 12" wide are applied vertically over each corner before the final layer of Grace Bituthene is applied. Corner joints should be filled with mastic first. If backfilling material includes rocks with sharp edges, a protection fabric over the membrane should be used before backfilling or install 3/4” or more rigid insulation board.

Foundation Waterproofing System
Grace Bituthene - 36"x66.7' long (1 roll/box): $140 per roll