Measurement of air permeance in mass timber elements assembled through the dovetail technique

Abstract

Adhesives and metal fasteners are important components in engineered wood products (EWPs), but the petroleum-based nature of adhesives raises environmental concerns and metal fasteners lead to challenges with end-of-life disposal and reusability. However, there is a promising solution in the form of ‘mass timber elements assembled through the dovetail technique (MTADT)’, also called ‘dovetailed massive wood board elements’, which is entirely composed of wood and devoid of adhesive or metal connections. However, existing literature on MTADT has focused on insufficient structural analysis and model testing of connection details rather than assessing the performance of a structural component. In this study, air permeance measurement in MTADT was conducted in accordance with the Finnish building code as part of the DoMWoB project (Dovetailed Massive Wood Board Elements for Multi-Story Buildings). The research aimed to explore the impact of storage conditions and moisture content on the air permeance values of three massive wood elements with varying dimensions. The smallest element had dimensions of 1160 mm × 1160 mm x 200 mm, while the other two were approximately 1300 mm × 1300 mm x 200 mm in size. The results from the air permeance tests indicated significant variability among the three test pieces, with q50 values of 1.4 m³/(m2h) for sample O, 2.9 m³/(m2h) for sample K, and 9.9 m³/(m2h) for sample Y. This data suggested that test piece Y demonstrates substantially higher air permeability compared to the other samples because it was the driest of these test elements.