Permanent Wood Foundation

Floors and roofs are covered with 2-inch planks. These serve as subflooring and roof sheathing, and, where tongue-and-grooved planking is used, provide an attractive finished floor and ceiling.

Ends of floor and roof beams are supported on posts which provide the wall framing. Supplementary framing between posts permits attachment of wall sheathing andexterior sidings. Details for this method of framing are provided in Plank and Beam Framing for Residential Buildings

– Wood Data No. 4, published by the American Forest & Paper Association (Appendix, Item 5).


The strength and resilience of wood construction is due to its framework of structural lumber combined with a covering of subflooring, wall and roof sheathing. Additional engineering of the system through use of floor and roof trusses and metal framing anchors provides even greater rigidity and permits wider spacing of floor and roof supporting members.


A firm foundation, consisting of properly installed footings of adequate size to support the , is essential to the satisfactory performance of all buildings.

Such foundations fully utilize the strength and resilience of construction.

Footings should extend below exterior grade sufficiently to be free of frost action during winter months. Where roots of are removed during excavation or when building on filled ground, the ground should be well compacted before footings are installed or concrete is poured.

Where poor soil conditions exist, satisfactory foundations may be constructed of treated timber piles capped with wood or concrete sills. Footing requirements are covered in the local building code. It is good practice, generally, to make the footing thickness equal to the thickness of the foundation wall and the footing projection equal to one-half the foundation wall thickness.

Two principal foundation types are commonly used.

These are concrete and pressure preservative treated wood.

Concrete footings with poured concrete or masonry block are most common. An increasingly popular foundation for houses and other wood frame buildings is the “Permanent Wood Foundation” which is accepted by all model building codes and the Department of Housing and (HUD).

Concrete Foundations

Concrete footings are frequently unreinforced. Where unstable soil conditions exist, however, reinforced concrete is used. This requires engineering analysis of the footing. The foundation wall may be of poured concrete or masonry blocks. Masonry block basement walls typically have a ½-inch coat of Portland cement mortar applied to the exterior. When set, the mortar parging is covered with two coats of asphalt to resist penetration of the wall and decay prevention are found in of Wood Structures for Permanence-Wood Construction Data No. 6 by ground water, Figure 5. Masonry block walls are capped at the top with 4 inches of solid masonry or concrete. Drain tiles are installed around the entire footing perimeter of concrete foundations. These lead to a storm drain or sump with pump to a positive drain.

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