Assessing carbon in timber buildings: how to factor in connections, fire protection and soundproofing

The embodied carbon of timber buildings is often miscalculated at early design stages. Primary materials in mass timber developments typically include glulam and cross-laminated timber, the volume of which is estimated and used to quantify upfront carbon emissions. However, to ensure like-for-like comparisons, the impact of metallic connections and, where needed, fire protection (boarding or treatment) and acoustic insulation should also be considered, even at early stages. This is particularly relevant when comparing timber against concrete schemes, which normally do not require additional allowances for connections, fire protection and soundproofing. This study suggests the upfront embodied carbon of a timber superstructure may increase by up to 60% in residential developments and 30% in commercial buildings when considering secondary components critical to the structure. Note that this is an initial study and that more real-world data should be collated to improve the accuracy of these findings, especially for residential buildings.