L1B – SAP calculations for heavily glazed extensions
If you build an extension where the glazing is greater than 25% of the floor area, then we can undertake a SAP assessment to demonstrate compliance with Approved Document L1B.
Using SAP, we can provide you with an economic and feasible solution to ensure your extension achieves compliance, no matter how much glazing you wish to include in the design.
Three steps to compliance:
Use SAP to calculate the CO2 emissions for the existing house along with the proposed extension.
Calculate the CO2 emissions for the existing house with a notional extension. A notional extension is an extension that meets the minimum standards of Approved Document L1B.
Compliance is achieved provided the “proposed” CO2 emissions are no greater than the “notional” CO2 emissions.