Evaluating the impact of thermal bridges on the thermal performance of concrete and mass timber buildings: Case study in Chile

Abstract

In building energy performance, the complexity of building envelopes in some areas determines a multidirectional heat transfer phenomenon, which, if not considered, would underestimate the actual thermal losses in a building. These phenomena are known as thermal bridges (TBs), and the present study addresses this issue. However, current research on thermal bridges has focused mainly on concrete or masonry structures, with limited attention to mass-timber (MT) systems, despite their growing international attention as a sustainable solution. In addition, Chilean regulations, despite having the wood resource, lack stringent criteria for thermal bridge assessment. To address these limitations, this study evaluates the effect of thermal bridges on the fa & ccedil;ade performance for concrete and MT post-platform construction typologies, considering two light-frame timber enclosure configurations and two volume/surface ratios in three cold-climate zones of Chile. Results show that, when TBs are considered, with fixed external insulation thickness (te) and varying internal insulation thickness (ti) in the timber-frame enclosure, thermal losses in concrete buildings are 26 %-32 % higher than in MT buildings. In the second configuration, fixing the ti and increasing te led to a reduction of TB impact from 35 % to 17 % in the concrete structure, and from 8-10 % to 2-5 % in the MT structure. The findings reinforce the thermal efficiency of MT construction and the relevance of continuous external insulation. This study supports the need to update Chilean regulations and offers a replicable approach for similar cold-climate contexts.