The Ontario Building Code | Prevention of Damage Due to Frost
126.96.36.199. Prevention of Damage Due to Frost
(1) Suitable precautions shall be taken during backfilling and grading operations to ensure that subsequent freezing of the soil will not cause uplift forces on the underside of cantilevered concrete steps to the extent that the steps or the walls to which they are attached will be damaged.
Section 9.9. Means of Egress