Highly Glazed commercial or residential extensions require SAP or SBEM Calculations to fulfil Part L1B or L2B Building Regulations. Since 7th April 2006, some conservatories greater then 30m², garden rooms, orangeries, extensions, and other new residential structures that are being added to an existing building, require a SAP (Standard Assessment Procedure) calculation. If you’re planning an extension and intend to include large areas of glazing, you may find the restrictions in Part L quite daunting.
Highly Glazed Residential and Commercial Extensions
Syntegra can help with your expansion plans by comparing the likely CO2 emissions of the property with the proposed extension to one with a notional extension and produce a report to show that the extension complies with Building Regulations. We create an 3D 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.
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.
Conversions
All conversions require either SAP (residential) or SBEM (commercial) calculations. The process is very similar to ‘new builds’ except the DER or BER does not need to be better than the TER in this case.
All other areas of SAP/SBEM must however comply, including minimum area weight U values for walls, floors, roofs and openings, minimum heating and cooling efficiencies, heating & lighting controls, minimum number of low energy light fittings etc.
We require a full set of plans together with our completed SAP/SBEM Form to carry out these calculations.