A thermal break is a material with low thermal conductivity placed in an assembly to reduce or prevent the flow of thermal energy between the inside and outside of a building. The two key functions of a thermal break are to insulate the building to reduce heat lost (through thermal/cold bridging) and to reduce the likelihood of internal condensation.

The thermal performance of the building envelope is a key design consideration in meeting today’s stringent energy efficiency standards such as Part L of the Building Regulations and other NHBC and BRE requirements which are fulfilled by way of reducing heat loss and the risk reduction of internal condensation. 

Thermal or cold bridges occur where the insulation layer is penetrated by a material with a relatively high thermal conductivity. Balcony connection points can cause a cold bridge from the cold balcony to the warm inside, so a thermal break must be specified to reduce heat loss and the risk of condensation forming at cold points inside the building.

Do I require a Thermal Break?

Balconies provide an attractive and practical architectural feature, however, because they pass through the building envelope, cold bridging can occur if the fixing detail is not thermally insulated.

The choice of balcony connector is not only key to structural integrity, it can also ensure the balcony is thermally isolated. Creating a thermal break will stop cold bridges and the resulting loss of heat. It will also stop condensation and any associated moisture damage and mould growth, which can be a hazard to health.

Minimising the effect of cold bridging on a building’s overall thermal performance is required to comply with Building Regulations (e.g. Part L). Useful guidance on this is available in BRE Information Paper IP/06 106: ‘Assessing the effects of thermal bridging at junctions and around openings’.

Thermal breaks are normally used to assist compliance in accordance with Part L of the Building Regulations by way of reducing heat loss and the risk of internal condensation.


Specifying a connector to provide a thermal break will vary depending on whether the application is concrete-to-concrete, concrete-to-steel or steel-to-steel.

Options include cast-in anchors which incorporate a thermal break, such as ‘off-the-shelf’ products from specialist suppliers such as Schöck.

Alternatively, specialist low-conductivity materials can be used (e.g. PTFE or similar high strength plastics), all of which would normally be used with stainless steel fixings (due to stainless steel having a much lower thermal conductivity to mild steel).


Consult Sapphire as we have experience of many proprietary systems and have conducted our own research and testing, so you don’t have to spend time and money inventing a thermal break solution from scratch. We can work with you to design and build beautiful balconies that are both structurally and thermally efficient.

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