Concrete buildings lose between 26 and 32 per cent more heat than mass timber buildings of identical typology when thermal bridges are included in the calculation, with the gap holding across three cold-climate zones in Chile. That is according to a peer-reviewed study by José Alberto Paz-Pérez, a doctoral researcher at the Centro Nacional de Excelencia para la Industria de la Madera (CENAMAD), and Manuel Carpio, a CENAMAD researcher, published in Case Studies in Thermal Engineering.
The research, co-authored with Rafael E. López-Guerrero of the University of Bío-Bío’s Faculty of Architecture, Construction and Design in Concepción, swapped the structural system between concrete and mass timber across identical post-platform geometries, with the light-frame timber wall enclosure held constant and volume-to-surface ratios varied through three Chilean cold-climate zones to isolate the structural system’s contribution to overall heat loss.
Wood Central understands that Carpio also holds an affiliation with the University of Granada’s Department of Construction Engineering and Project Management in Spain, and that the Spanish Código Técnico de la Edificación serves as one of the international benchmarks against which the team measured Chile’s thermal-bridge framework, alongside the Canadian regulatory tradition.
In the concrete typologies, thermal bridges accounted for as much as 35 per cent of total envelope heat losses, falling to 17 per cent only when continuous exterior insulation was thickened across the modelled scenarios. By comparison, the mass timber typologies recorded thermal-bridge contributions of 8 to 10 per cent under the same baseline, dropping to between 2 and 5 per cent once the exterior insulation thickness was matched across the test cases.
The authors attribute the difference to linear transmittance (Ψ) values at structural junctions, with mass timber connections recording significantly lower Ψ-values than equivalent concrete joints, where the structural interfaces concentrate heat flow out through the envelope.
Two insulation strategies were tested in the modelling: the first held the exterior insulation fixed whilst varying the interior thickness, and the second reversed the approach, fixing the interior layer and increasing the exterior. The second strategy delivered the greater reduction in thermal-bridge losses across both materials, cutting the bridges’ contribution most aggressively in the concrete structures where the thermal-bridge penalty was highest.
“Chilean regulations, despite having the wood resource, lack stringent criteria for thermal bridge assessment,” the authors wrote, calling for an update of Chile’s thermal evaluation framework with calculation procedures and more demanding criteria for thermal-bridge treatment, and offering their own methodology as replicable for jurisdictions sharing similar climates and post-platform construction.
It comes as Wood Central reported a wider wave of mass timber research through 2025 and 2026, from Chilean researchers putting radiata pine cross-laminated timber to the test against extreme seismic loads through to a USDA-led study projecting a 25-to-40-fold lift in US mass timber demand to 2070, with the comparative question of timber and concrete now widening from structural and embodied-carbon grounds into cold-climate energy performance.
For more information: José Alberto Paz-Pérez, Rafael E. López-Guerrero, Manuel Carpio, Evaluating the impact of thermal bridges on the thermal performance of concrete and mass timber buildings: Case study in Chile, Case Studies in Thermal Engineering, Volume 74, 2025, 107014, ISSN 2214-157X, https://doi.org/10.1016/j.csite.2025.107014.
