Extensions

Highly Glazed Residential & Commercial Extensions


Residential or commercial extensions with large areas of glazing require SAP or SBEM Calculations to fulfil Part L1B or L2B Building Regulations. We create an energy model of the building with the proposed extension on the basis of the proposed area of glazing, proposed U-Values of the building fabric etc and calculate the annual carbon emissions. We create another energy model of the building with a standard area of glazing, standard U values etc. Providing the property with the proposed extension emits less carbon than the notional extension this will comply with Building Regulations requirements. This means that the heat loss from the large amount of glazing can be offset by improving the energy efficiency of the floors, walls and roof. Building Regulations also allows upgrades to the existing property to be taken in to account to offset the heat losses from the additional glazing in the proposed extension.

To download our guide to SAP please click here.

Large Commercial Extensions

Where the proposed extension to a commercial building has a total useful floor area of more than 100m2 and is greater than 25% of the total useful floor area of the existing building the work has to be regarded as a new building. Therefore full SBEM Calculations are required to fulfil Building Regulations requirements and the extension will have to be designed, specified and built to fulfil the more stringent ‘new-build’ requirements. This type of extension will also require an air leakage test on completion.

To download our guide to SBEM please click here.