Saturday, 3 October 2015

I don't need to worry about thermal bridging... do I?

If you read our first post - maybe even if you didn't - you understand what thermal bridging is. So what does it all mean for designers, assessors, inspectors and builders? There are two main problems that thermal bridging causes. The first is increased heat loss, as discussed previously. This increased heat loss increases heating bills and carbon emissions associated with heating, which impacts on the climate change as well as Part L calculations. There may also be an adverse impact on alternative energy assessments such as Passivhaus. Part L
We've undertaken some simple research to quantify the impact of thermal bridging on a typical SAP calculation, and found that moving from the default values to best-practice detail design can reduce the BER by up to 10%. This is clearly significant, and could mean the difference between a pass and a fail, or the need to fit PV’s or the ability to omit them.
The second problem is that internal surface temperatures will be reduced locally around a thermal bridge. If this reduction is significant, it can result in less than optimal thermal comfort, surface condensation and mould. This issue can be visualised in finished buildings using a thermal imaging camera, or at design stage by plotting the isotherms on the 2D simulation.
Minimising thermal bridging is therefore an important aspect of the design of any building, and it is our responsibility as professionals in construction to ensure this is done in order to deliver quality and value to our clients.

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