Towards quantifying the air leakage through cross-laminated timber

This study aims to contribute to limited research evidence for evaluating air leakage through Canadian manufactured CLT, by initiating research to characterize and quantify air leakage paths across CLT panels and evaluate the impact of additional air barrier system components on CLT. Understanding air leakage across CLT is important to the continuous development of design and construction practices towards ensuring the performance of CLT buildings. Through experimental testing of various panel parameters, metrics including the air leakage rate, normalized equivalent leakage area, as well as the flow exponent and flow coefficient were measured. For 3-ply and 5-ply CLT panels utilized in this research, significant air leakage through panel edges compared to air leakage through the panel face was observed due to unglued edge joint gaps typical to Canadian manufactured CLT. Further, sealing panel edges with an effective air barrier material such as a self-adhered membrane to reduce air leakage from 4 - 12 L/sm2 to 0.09 - 1.4 L/sm2 was not enough to meet more stringent thresholds for air barrier assemblies at 0.1 L/sm2 at a 75 Pa pressure differential.