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Foundation: n. the base or substructure of a building. The harsh Canadian climate dictates new buildings constructed in this country have part of their structure underground, below the frost line (the depth to which the ground freezes during our the winter). This underground component of a structure is commonly referred to as the foundation or basement. Full basements are generally six to seven feet underground, whereas a "high ranch" or split entry style foundation will have only the minimum requirement of four to five feet of frost cover. A foundation consists of a footing, typically six to eight inches thick and twenty to twenty four inches wide, resting directly on the undisturbed ground at the bottom of the excavation. On the footing a wall is constructed (the basement wall) of poured concrete, block, or pressure treated lumber. Most new foundations constructed today are of the poured concrete variety. Block was once much less expensive than concrete and therefore widely used. It is still used occasionally by do-it-yourselfers and in areas where ready-mixed concrete is unavailable. Pressure treated foundations have been slow to gain consumer acceptance, and are widely considered to be a detriment to the resale value of a new home. A foundation drainage system is required by recent amendments to the Ontario Building Code. Under the Ontario New Home Warranty Plan, basements must be warranted by the builder against leakage for two years. A typical system consists of four inch perforated drain pipe (the weeping tile) surrounding the basement portion of the structure. It is not required around the garage portion of the foundation. The tile is covered in six inches of crushed stone that serves as a filter material. The concrete foundation wall must be water- or damp-proofed using one of three approved methods:
[NB: Ontario Building Code officials have recinded the more stringent drainage layer requirements. A ruling widely regarded as a technological step backwards now permits home builders to backfill basement walls with virtually any material, provided a damp-proofing tar layer is first applied to the concrete. (The requirement for a drainage layer or membrane is removed, in spite of the tremendous reduction in "leaky basement" warranty claims brought about directly by the more stringent requirements.) The new ruling is a direct result of pressure from large southern Ontario builders who claim the additional cost was making new homes too expensive. It is this contractors opinion that the few hundred dollars in up-front savings is going to result in poorer-quality, more leak-prone foundations.] The framed (wooden) portion of the structure is attached to the top of the foundation wall using anchor bolts set in the concrete at five to eight foot intervals. It is extremely important that the top of the foundation wall be level, true, and square to prevent problems propagating throughout the entire construction process. A reputable forming contractor should guarantee the dimensional accuracy of his work within an acceptable range - plus or minus one quarter inch. The installation of various concrete slabs (the basement and garage floors, and porch slab) usually completes the foundation construction process. Key Benefits
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