Code Library › Volume 1 › Section 9.13 — Dampproofing, Waterproofing and
PART 9 — HOUSING AND SMALL BUILDINGSUpdated for the 2024 Ontario Building Code

9.13.3.3.Preparation of Surface

(1) Surfaces to be waterproofed shall be prepared in accordance with the instructions of the waterproofing material manufacturer. (2) Where the waterproofing material is to be applied on ICF walls, the instructions of the ICF wall manufacturer shall be followed. (3) Unit masonry walls that are to be waterproofed shall be parged on exterior surfaces below ground level with not less than 6 mm of mortar conforming to Section 9.20. coved over the footing. (4) Concrete walls that are to be waterproofed shall have all holes and recesses sealed with mortar or waterproofing material. (5) Surfaces required to be waterproofed shall be clean and dry and free of ice, snow, frost, dust, dirt, oil, grease, cracks, projections and depressions, loose particles and debris that could be detrimental to the performance of the waterproofing material.
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Common questions about this part of the code

When is waterproofing required instead of dampproofing for a foundation in Ontario?What are the radon and soil gas control requirements for new houses in Ontario?Does foundation dampproofing go on the inside or outside of the wall in Ontario?

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Code text is reproduced for reference from the Ontario Building Code (O. Reg. 163/24, 2024 Building Code Compendium). This page is provided for general information and is not an official copy. Always verify requirements against the official Ontario Building Code and confirm with your local building department.