Tempo:
window to allow for escape in the event of emergency. Additional clearance is required for outward-opening awning windows.
BACKFILLING Place backfill after the first floor joists and subfloor are in place because they provide lateral support for the foundation walls. This applies to concrete, ICF, masonry and preserved wood foundation walls. Table 5 (p. 265) shows the maximum height from basement floor to finished grade for both laterally supported and laterally unsupported foundation walls. Backfill material within 600 mm (24 in.) of the foundation should be free-draining granular material (not subject to ice lensing). It should be free of large rocks, clay clumps, construction waste and pyritic shales. These materials can cause pressure points on the foundation wall, damage dampproofing or waterproofing membranes, and impair proper drainage around the foundation. Unequal backfill loading against foundation walls can cause movement or cracking. Therefore, deposit backfill material uniformly around the perimeter in small lifts. Compact each lift before the next one is placed. Ensure that externally mounted insulation, drainage material, dampproofing or waterproofing membranes are not damaged.
FOUNDATION INSULATION Foundation (basement) walls are required to be insulated if they enclose conditioned space. Basement floors with radiant heating must be insulated underneath. The levels of insulation required are determined by the climate zone in which the house is built. See Chapter 5 for more detailed information. Foundations can be insulated on the interior or the exterior of the building. Foundation walls enclosing conditioned space should be insulated
along their full height. To reduce the possibility of trapped moisture, it is recommended that concrete foundation walls insulated on the interior be left exposed for several months so that they lose excess moisture before the insulation is applied. When batt insulation supported by wood framing is used, interior dampproofing material must be used to separate the framing from the concrete walls. With framing in place, it is relatively economical to add drywall to create a finished wall. When spray-foam or polystyrene insulation is installed on the interior of basement walls, it must be covered by a barrier such as drywall to protect it in the event of fire. Basement walls can also be insulated on the exterior. Some exterior insulation products also serve as a wall drainage layer. The portion of the insulation that extends above grade must be covered by a protective material.
FOOTINGS AND FOUNDATIONS FOR CRAWL SPACES Crawl spaces are enclosed spaces between the underside of a floor assembly and the ground below, where the clearance is less than the minimum 2 m (6 ft. 6 in.) required for a basement and less than 25 per cent of their area above ground is open to the outdoors. Crawl spaces are often used to give access to ducts, pipes, cables and other utilities and can be heated (conditioned) or unheated (unconditioned). If a crawl space is unheated, it is essential to have an effective air barrier between the conditioned and unconditioned space. As for other types of foundations, footings for crawl spaces must be placed at a depth below grade determined by soil conditions and frost penetration (see Table 3 on p. 265). Footing sizes are generally the same as those used to support basement walls. Crawl space walls may be built
BACKFILLING Place backfill after the first floor joists and subfloor are in place because they provide lateral support for the foundation walls. This applies to concrete, ICF, masonry and preserved wood foundation walls. Table 5 (p. 265) shows the maximum height from basement floor to finished grade for both laterally supported and laterally unsupported foundation walls. Backfill material within 600 mm (24 in.) of the foundation should be free-draining granular material (not subject to ice lensing). It should be free of large rocks, clay clumps, construction waste and pyritic shales. These materials can cause pressure points on the foundation wall, damage dampproofing or waterproofing membranes, and impair proper drainage around the foundation. Unequal backfill loading against foundation walls can cause movement or cracking. Therefore, deposit backfill material uniformly around the perimeter in small lifts. Compact each lift before the next one is placed. Ensure that externally mounted insulation, drainage material, dampproofing or waterproofing membranes are not damaged.
FOUNDATION INSULATION Foundation (basement) walls are required to be insulated if they enclose conditioned space. Basement floors with radiant heating must be insulated underneath. The levels of insulation required are determined by the climate zone in which the house is built. See Chapter 5 for more detailed information. Foundations can be insulated on the interior or the exterior of the building. Foundation walls enclosing conditioned space should be insulated
along their full height. To reduce the possibility of trapped moisture, it is recommended that concrete foundation walls insulated on the interior be left exposed for several months so that they lose excess moisture before the insulation is applied. When batt insulation supported by wood framing is used, interior dampproofing material must be used to separate the framing from the concrete walls. With framing in place, it is relatively economical to add drywall to create a finished wall. When spray-foam or polystyrene insulation is installed on the interior of basement walls, it must be covered by a barrier such as drywall to protect it in the event of fire. Basement walls can also be insulated on the exterior. Some exterior insulation products also serve as a wall drainage layer. The portion of the insulation that extends above grade must be covered by a protective material.
FOOTINGS AND FOUNDATIONS FOR CRAWL SPACES Crawl spaces are enclosed spaces between the underside of a floor assembly and the ground below, where the clearance is less than the minimum 2 m (6 ft. 6 in.) required for a basement and less than 25 per cent of their area above ground is open to the outdoors. Crawl spaces are often used to give access to ducts, pipes, cables and other utilities and can be heated (conditioned) or unheated (unconditioned). If a crawl space is unheated, it is essential to have an effective air barrier between the conditioned and unconditioned space. As for other types of foundations, footings for crawl spaces must be placed at a depth below grade determined by soil conditions and frost penetration (see Table 3 on p. 265). Footing sizes are generally the same as those used to support basement walls. Crawl space walls may be built
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