9.12.2.2.Minimum Depth of Foundations

(1) Except as provided in Sentences (4) to (7), the minimum depth of foundations below finished ground level shall conform to Table 9.12.2.2. Table 9.12.2.2. Minimum Depths of Foundations Forming Part of Sentence 9.12.2.2.(1) Minimum Depth of Foundation Containing Minimum Depth of Foundation Containing Type of Soil Heated Basement or Crawl Space(1) No Heated Space(2) Good Soil Drainage Poor Soil Drainage Good Soil Drainage Poor Soil Drainage Rock No limit No limit No limit No limit Below the depth of frost Coarse grained soils No limit No limit No limit penetration Below the depth of frost Below the depth of frost Silt No limit No limit penetration(3) penetration Clay or soils not 1.2 m but not less than the 1.2 m but not less than the 1.2 m(3) 1.2 m clearly defined(4) depth of frost penetration(3) depth of frost penetration Notes to Table 9.12.2.2.: (1) Foundation not insulated to reduce heat loss through the footings. (2) Including foundations insulated to reduce heat loss through the footings. (3) Good soil drainage to not less than the depth of frost penetration. (4) See Note A-Table 9.12.2.2. (2) Where a foundation is insulated in a manner that will reduce the heat flow to the soil beneath the footings, the foundation depth shall conform to that required for foundations containing no heated space. (See Note A-9.12.2.2.(2)) (3) The minimum depth of foundations for exterior concrete steps with more than 2 risers shall conform to Sentences (1), (2) and (5). (4) Concrete steps with 1 and 2 risers are permitted to be laid on ground level. (5) The foundation depths required in Sentence (1) are permitted to be decreased where experience with local soil conditions shows that lesser depths are satisfactory, or where the foundation is designed for lesser depths. (6) The foundation depths required in Sentence (1) do not apply to foundations for (a) buildings (i) that are not of masonry or masonry veneer construction, and (ii) whose superstructure conforms with the requirements of the deformation resistance test in CSA Z240.2.1, “Structural requirements for manufactured homes,” or (b) accessory buildings (i) that are not of masonry or masonry veneer construction, (ii) not more than 1 storey in building height, (iii) not more than 55 m² in building area, and (iv) where the distance from finished ground to the underside of the floor joists is not more than 600 mm. (7) The foundation depths required by Sentence (1) do not apply to foundations for decks and other accessible exterior platforms (a) of not more than 1 storey, (b) not more than 55 m² in area, (c) where the distance from finished ground to the underside of the floor joists is not more than 600 mm, (d) not supporting a roof, and (e) not attached to another structure, unless it can be demonstrated that differential movement will not adversely affect the performance of that structure.