Illustration Source: Owens Corning

3.1.1.7. (5) Except as provided in Sentence (6) and (7), where a portion of the basement slab or a portion of a basement slab edge is the only part of the slab that is at the exterior ground level, those portions shall have perimeter insulation extend not less that 600 mm (24") of the exterior ground level, those portions shall have perimeter insulation extend not less than 600 mm (24") below the slab level. (See Appendix A.)

(6) Where the entire concrete slab is within 600 mm (24") of the exterior ground level, the entire surface of the slab shall be insulated. (See Appendix A.)

(7) Where a slab contains heating ducts, pipes, tubes or cables, the entire heated surface of the slab that is in contact with the ground shall be insulated.