| Abstract | A benchmark assembly and a series of ten client wall assemblies were developed as part of the project “Performance Evaluation of Proprietary Drainage Components and Sheathing Membranes when Subjected to Climate Loads”.
The purpose of this project was to assess the performance of wall drainage components and sheathing membranes (drainage system) in their ability to provide sufficient drainage and drying in Canadian climates with a moisture index (MI) greater than 0.9 and less than 3400 degree-days, or MI greater than 1.0 and degree days ≥ 3400 (primarily coastal areas). In these regions, the 2010 National Building Code requires a capillary break behind all Part 9 claddings. Currently, acceptable solutions to the NBC capillary break requirement include:
(a) A drained and vented air space not less than 10 mm deep behind the cladding;
(b) An open drainage material, not less than 10 mm thick and with a cross-sectional area that is not less than 80% open, behind the cladding;
(c) A cladding loosely fastened, with an open cross section (i.e. vinyl, aluminum siding)
(d) A masonry cavity wall or masonry veneer constructed according to Section 9.20 (i.e. 25 mm vented air space)
In this project, the performance of proposed alternative solutions for the capillary break was compared through laboratory evaluation and modeling activities to the performance of a wall built to minimum code requirements. The proposed drainage system would be deemed an alternative solution to the capillary break requirement in the National Building Code for use with all code compliant Part 9 claddings provided it exhibits adequate moisture performance as compared to a NBC-compliant benchmark wall assembly.
In This Report — A set of reliable and representative hygrothermal property data were generated of a number of selected building materials, including all drainage components and sheathing membranes, for hygrothermal simulation of wall assemblies.
In addition to regular measurements, additional tests were conducted to quantify the air flow performanc of several drainage components used in the drainage cavities of the client recommended wall assemblies. |
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