The Ontario Building Code | Required Moisture Protection

5.8.2.1. Required moisture Protection

(1) Except as provided in Sentence (2), where a building element separates interior space from the ground, materials, components or assemblies shall be installed to prevent moisture transfer into the space.

(2) Materials, components or assemblies need not be installed to prevent moisture transfer from the ground where it can be shown that such transfer will not adversely affect any of,

(a) the health or safety of building users,

(b) the intended use of the building, or

(c) the operation of building services.