Buildings Part L - Thermal Bridging Calculations

A Thermal Bridge (also known as a cold bridge) is a mechanism of heat transfer where a break in insulation occurs. This is typically caused by non-insulating of high conductivity materials, resulting in heat transfer. A thermal bridge will typically occur at junctions between two elements such as walls and roofs where the insulation isn’t continuous.

A thermal bridge is expressed as a linear transmittance value (Ψ-value [Psi]). Ψ-values are used to calculate a cumulative Y-value which allows calculation of the building’s overall heat loss through thermal bridges.

Thermal bridging can have a large impact on energy use, heat loss and condensation; therefore it is important to consider mitigating the effects of thermal bridging from an early stage. Building Regulations require that thermal bridging is considered within SAP and SBEM calculations.

Thermal Bridging has a significant role to play within Building Regulations Part L and the Code for Sustainable Homes; particularly if the higher levels of the code are sought.

Energy Council can offer bespoke thermal bridging calculations to assist with any thermal bridging problems. We will run specialised calculations on your details to identify where problematic bridges will occur and provide cost effective and reliable solutions to minimise cold bridges and their impact.