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Towards a Methodological Approach to Builder Specific, Preconstruction Airtightness Estimates for Light-Framed, Detached, Low-Rise Residential Buildings in Canada

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posted on 08.06.2021, 08:15 by Bomani Khemet, Russell Richman
Towards A Methodological Approach to Builder Specific, Preconstruction Airtightness Estimates for LightFramed, Detached, Low-Rise Residential Buildings in Canada Bomani Khemet, Doctor of Philosophy in Civil Engineering, Ryerson University, 2019 This research is an investigation into residential building airtightness. Its purpose is to establish a methodology to predict preconstruction airtightness in Canadian homes. The dissertation presented an analysis of a large, national blower door testing population, numbering over 900,000 low-rise detached homes. The relationship between airtightness and various building factors, such as; insulation levels, building size, and year of construction, is explored. Regressionbased models were found to be highly significant (p<<0.01) and explained up to 48% (R = 0.69, p<<0.01) of whole building airtightness. The national models’ scope was confined to predicting airtightness in existing homes with heterogeneous wall construction. In order to estimate preconstruction airtightness in conventionally constructed homes, a local blower door testing population of nearly 3000 homes was examined. Three builder-specific, geometricbased, temporally independent, multiple linear regression models were developed. Some of these builder-specific models were found to be strong, and explained over 58% (R = 0.79, p<<0.001) of whole building airtightness. A five variable, geometrically based model which controlled for handicraft was found to be very strong, explaining up to 73% (R = 0.87, p<<0.001) of the whole building airtightness. The regression-based analyses on the local population suggests that air leakage is prominent through two building details: the floor-to-wall details, and at the window-to-wall assemblies. An empirically based design of experiments was devised to quantify the impact of air leakage through a floor-to-wall detail. A very strong laboratory-based model explained up to 88% of the air leakage through the floor-to-wall joint (R = 0.95, p<<0.001). A builder-specific, temporally-independent model was combined with the empirically-based, floor-to-wall model to illustrate the applicability of the approach residential building designers. The synthesis of the two models resulted in a novel, whole building, preconstruction airtightness forecasting model. The dissertation demonstrated that airtightness in homes could be estimated with temporally independent, builder-specific, and geometrically-based preconstruction models. The estimation approach spurred models that were stronger in explanatory power, and industrial applicability as compared to previous airtightness models.





Doctor of Philosophy


Civil Engineering

LAC Thesis Type


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