thermal bridge calculations

Thermal Bridging Calculations | PSI Values | Surface Condensation

2d and 3d thermal bridging calculations for non repeating junctions for use in sap calculations or for condensation analysis

Thermal Bridges occur at junctions where two or more building elements join or where there is a change in structure. These thermal bridging result in increase heat loss and reduced surface temperature. We provide thermal bridging calculations to calculated this increase heat loss and to establish risk of surface condensation to temperature reduction at the bridge.

thermal bridging calculations

What are thermal bridging calculations?

There are two types of thermal bridging calculations, repeating thermal bridging and non-repeating thermal bridging.

Repeating thermal bridging

Previously it was acceptable to calculation heat loss through the building fabric as a parallel set of resistances. However, modern u-values are calculated to include repeating thermal bridging such as timber stud and mortar joints. This type of thermal bridging calculation is included as part of the sap calculations at no additional costs.

Non-repeating thermal bridging

These calculation are used to calculate the extra heat transfer through the building fabric due the the presence of a junction such as junctions at floor, roofs, corners and around openings. This calculation is derived from numerical modelling.

How can we help?

We provide both 2D and 3D thermal bridging calculations using the latest modelling software. Our thermal bridging calculation provide the increase heat loss associated with the junction, this can the be multiplied by the junction length to get the total extra heat loss.

As part of the calculation we will also provide the the critical surface temperature at which surface condensation would occur.

We can suggest ways in which heat loss through the bridge can be reduced through the use of improved detailing around the junction. Calculating individual PSI values for specific junctions help the SAP meet current Building Regulations, in particular lintel and floor junctions.

There are other options you can consider when trying to improve the SAP Rating of your development. A good way it to use pre-existing thermal bridging details such as Constructive Details or those published by Local Authority Building Control.

Want to know more?

If you would like to know more about our thermal bridging calculations, discuss your project requirements, or get a quote then please do get in touch. We look forward to working with you on your next project.
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