Abstract

In the Canadian climate, the performance of wood-frame building envelopes is affected directly by moisture management as well as by the quality of design, construction workmanship, and maintenance. Trapped moisture reduces the thermal performance of the envelope and can lead to mould growth that deteriorates building materials and contaminates the indoor-air. The means to evaluate the impact of these factors on the overall performance of the envelope are limited. Computer models that exist are still, for the most part, reserved for researchers or have not been validated to a sufficient comfort level for the designer. Till now large scale testing that would provide realistic results have been limited due to the lack of facilities and the lack of evaluation procedures. This research project develops a protocol that facilitates the evaluation of the performance of light-frame building envelopes. The protocol evaluates the building envelope as a system under the following main issues: air-tightness, moisture management performance, thermal performance, energy performance, structural stability of building envelope, acoustic performance, fire response performance and quality of workmanship. It sets the internal and external loads that affect that performance and develops a procedure for evaluation. The evaluation protocol includes performance criteria, associated standards, and compliance evaluation methods. The second part of this study involves developing an assessment tool that uses data generated by the above evaluation procedure. This assessment tool is designed to provide a fast check of the building envelope system compliance against performance requirements. Intended to be comprehensive and user-friendly for professionals, this tool can also be used by producers and exporters of factory-made houses in Canada to examine existing designs and to verify the performance of new designs. The validation of the protocol and the assessment tool is done by evaluating the performance of five different building envelope assemblies: one modular prefabricated house designed and built in conformance with the requirements of NBC and Québec Energy Code (A-standard house), one modular prefabricated house designed to conform to requirements of Novoclimat program (A-Novoclimat house), one panellised high performance house (M-Thermo house) and two Advanced houses: NOVTEC Advanced house and Innova Advanced house. The results of validation show that the protocol and the assessment tool are effectively used to establish the performance profiles of these five case studies, demonstrating in each case the adequacy of each parameter. The results also demonstrate that the protocol provides a means of comparing the relative performance of respective parameters across case studies.