A thermal bridge is an area of a heat loss element within a building envelope which has a higher thermal conductivity than the majority of the materials within the build-up of a thermal element. (E.g. timber stud in a timber frame wall)
Thermal Bridging Calculations
Within a SAP calculation there are 2 options for imputing the Y-Value for thermal brides. Either the default Y-Value of 0.15W/m2K or by calculating out the specific Y-Value for that dwelling through measuring the length of junctions and using the associated Psi value for that junction build up as specified by the architect. Building control have a certified list of junctions and associated Psi value to work from. In most cases undertaking the thermal bridging calculation will result in a 50% improvement in Y-Value and give you greater flexibility in the remaining specification of your project to show compliance with energy requirements.
Thermal Junction Modelling (PSI Values)
Not all thermal junctions are standard. If this is the case with your project, ‘360 Energy’ will be able to provide simple and complex details in 2D and 3D to determine the Psi value for that junction and advise if there are areas within the junction which need to be addressed or improved upon.