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This technical document provides additional guidance relating to what thermal bridging (often referred to as cold bridging) is and how to prevent it in your construction project.
Construction projects incorporate the use of a variety of materials in differing situations, locations and build-ups. This can often lead to thermal bridging and can result in heat loss through the building fabric and mould growth where warm internal air comes into contact with a cold surface and condensates. This technical document aims to provide additional guidance around what thermal bridging is and how it can be prevented.
Thermal bridging is where there is a direct link between the inside and outside is formed through building elements that are more thermally conductive than the rest of the building fabric.
Thermal bridging is commonly formed (but not limited to) in the following scenarios:
The above provides some examples of how to prevent thermal bridging. Your project structural engineer and designer will be able to prevent thermal bridging by designing it out, however the most effective and efficient way of dealing with thermal bridging is understanding how it works and analysing a building design prior to works commencing on site.
At the start of the project, we carry out a Site Risk Assessment which is a meeting on site, between the site manager and the warranty surveyor (and other stakeholders if needed) to go through the main risks for our insurer and outlining how they will be managed; thermal bridging should be discussed at this stage.
If, for example, balconies are proposed, the following should be ascertained
If the wider cavity wall widths are adopted for example, it should be established if the designer has specified low thermal conductivity wall ties. If they haven’t or the site manager and warranty surveyor are unsure, this should be set as a condition on the Site Risk Assessment Report.
This article has provided some background information with what thermal bridging is, common situations where you may find thermal bridging in your construction project and how to prevent it. Thermal bridging should be considered before works commence on site by your design team and should be discussed during the Site Risk Assessment with the site manager and the warranty surveyor.
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Every care was taken to ensure the information in this article was correct at the time of publication. Guidance provided does not replace the reader’s professional judgement and any construction project should comply with the relevant Building Regulations or applicable technical standards. For the most up to date Premier Guarantee technical guidance please refer to your Risk Management Surveyor and the latest version of the Premier Guarantee Technical Manual.