Abstract: A vapour barrier refers to any material used to restrict the movement of water vapour. It may take the form of a coating, membrane, or board, but is normally a sheet material designed to fulfil this one particular function. The correct selection of a vapour barrier is influenced largely by the peculiarities of the application for which it is intended, and involves consideration of other properties of the material in addition to its water vapour permeance. These properties vary widely with different vapour barriers, and no one material is necessarily suited to all applications. The conditions to which the vapour barrier is exposed after installation are a factor, but the circumstances during application are usually of most importance. The most important general principle to be followed in both design and installation is to reduce to a minimum the number of openings in the barrier. Where such openings are necessary, special care should be taken seal the barrier so as to approach complete continuity.
Canadian Building Digest; no. CBD-9, ISSN:
0008-3097, Publication date:
1960-09
