SBEM Calculations for Extensions

SBEM Calculations for Extensions

SBEM Calculations for extensions offer greater flexibility with building design and are required for larger commercial extensions. A large extension is essentially treated as a new complex building and will therefore need to adhere to the standards and regulations set out for new commercial buildings.  

Feel free to give Elmhurst Energy Consultancy a call if you are unsure whether or not your extension requires an SBEM Calculation. Either way, we can help you with information or calculations. 


Whole Building Calculation Method 

U-Value Calculations can be undertaken to determine that the new thermal elements introduced as part of the extension meet the required standards established in Building Regulations/Standards. However, limits on the amount of glazing and thermal elements may make the building design tricky. A Whole building calculation method uses SBEM to provide greater design flexibility and demonstrate reasonable provision towards compliance. 

An SBEM Calculation will demonstrate that the CO2 emissions for the building and proposed extension, do not exceed that of the building and a notional extension, which already complies with the standards.


When are SBEM Calculations Required for Extensions?

Not all extensions for non-dwellings require an SBEM Calculation, however, large extensions will need an SBEM Calculation if:

  • The floor area is greater than 100m2


  • the total useful floor area of the extension is more than 25% of the existing building floor area 

According to regulations if your building meets the above criteria then it will be treated as a new building and will have to comply with the more stringent Building Regulations/Standards which applies to new buildings.

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01455 883 259

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