The Ontario Building Code | Protective Material and Component Properties
5.8.2.2. Protective Material and Component Properties
(1) Except where it can be shown that lesser protection will not lead to adverse conditions, or as provided in Article 5.8.2.3., materials and components installed to provide required moisture protection shall conform to the requirements of this Article.
(2) Except as provided in Sentences (3) and (7), materials installed to provide the required moisture protection shall be capable of bridging,
(a) construction, control and expansion joints,
(b) junctions between different building assemblies, and
(c) junctions between building assemblies and elements penetrating building assemblies.
(3) Except as provided in Sentence (7), where the material installed to provide the required moisture protection is not capable of bridging construction, control and expansion joints, those joints shall be designed to maintain the continuity of the moisture protection.
(4) Materials and components installed to provide the required moisture protection shall have sufficiently low water permeance to resist moisture loads.
(5) Except as provided in Sentence (7), moisture protection shall be designed and constructed to resist design hydrostatic pressures as determined in accordance with Section 4.2.
(6) Except as provided in Sentence (7), materials covered in the scope of the following standards shall not be installed to provide the required resistance to moisture transfer:
(a) CGSB 37-GP-6Ma, "Asphalt, Cutback, Unfilled, for Dampproofing", or
(b) CGSB 37-GP-18Ma, "Tar, Cutback, Unfilled, for Dampproofing".
(7) Where the substrate is cast-in-place concrete, and a drainage layer is installed between the building assembly and the soil, and the assembly will not be subject to hydrostatic pressure,
(a) materials and components installed to provide the required resistance to moisture transfer need not conform to Sentences (2), (3), (5) and (6), and
(b) materials covered in the scope of the following standards are permitted to be installed to provide the required resistance to moisture transfer where those materials conform to the requirements of the standards:
(i) CGSB 37-GP-6Ma, "Asphalt, Cutback, Unfilled, for Dampproofing", or
(ii) CGSB 37-GP-18Ma, "Tar, Cutback, Unfilled, for Dampproofing".
In Plain Language
Except where lesser protection can be shown adequate, materials and components providing moisture protection must meet minimum property requirements ensuring they actually resist ground moisture over time.
This is a plain-language summary of the 2012/2017 Ontario Building Code text above, for general understanding only and not a substitute for the Code. Always confirm current requirements against the 2024 edition (O.Reg. 163/24) or a qualified professional before construction.