What is an Excessive Glazing SAP calculation?

For extensions to existing dwellings, building regulations allow for a maximum glazing area of 25% of the floor area and the total area of any openings removed as a result of building the extension.

Many contemporary designs look to incorporate glazing areas in excess of this 25% allowance, which is where you need to justify the design through an excessive glazing calculation.

We will need plans and  information about the existing house including:

•         Existing floor plans

•         Existing elevations

•         Existing sections

•         Block plan showing orientation of building

•         Age of property

•         Heating and hot water

•         Details of floors walls and roofs

We will then need information about the extension including:

•         Proposed floor plan

•         Proposed elevations

•         Proposed sections

•         Glazing schedule

•         Detailed construction specification for the extension

We use this information to generate SAP calculations to prove that, despite the glazing design exceeding the 25% allowance, the extension can be justified. This is achieved by design improvements to the extension, or occasionally the existing house,  where household carbon emissions are shown to be no worse than an extension which was built to the 25% glazing allowance.

What does the service include?

You will get a covering report detailing the findings with corresponding SAP calculation sheets to meet the requirements of your building control body.

If you would like a quote for this service please click the button below.