Thermal Bridging – PSi Value Assessments

A thermal bridge is an area of a construction where the cold from the outside can pass through the structure more easily than in the rest of the structure. These bridges generally occur in areas that are more difficult to insulate, such as where two different elements of a dwelling meet e.g. the junction between a wall and floor or the junction between a wall and a window.

Thermal bridges can lead to cold areas on internal surfaces and, if these areas are cold enough, condensation can form, which in turn can lead to mould growth.

We can assess thermal bridges and calculate their linear thermal transmittance (also known as the PSi value or Ψ value) and temperature factor to evaluate the risk of surface condensation and mould growth. Where a risk of condensation is found, we can also recommend insulation solutions, the Alreflex ColdBreak and Thermaedge products are specifically designed for this purpose.

Details of thermal bridges can be included in SAP and SBEM assessments to help achieve Building Regulation compliance.

We calculate the linear thermal transmittance (Ψ value) and temperature factor of junctions by finite element analysis steady-state heat flow through a 2D / 3D model. All of our thermal bridging calculations comply with BS EN ISO 10211: 2007 and BR 497.

If you would like to understand more about our thermal bridging service and some of our specifically designed solutions that can be used to meet the correct PSi values, please contact our Technical Department on 01582 544255 or email [email protected].