EXTENSION SAP CALCULATIONS

If you are building an extension, Part L1b of the building regulations requires existing dwellings to have a SAP (Standard Assessment Procedure) calculation if they are considered excessively glazed. This occurs when an extension includes glazing that exceeds 25% of the extension's floor area.

The requirements for residential extensions are not as strict as new build standards, allowing for existing elements of the building to be incorporated into the design.

We use the whole dwelling calculation method assesses the dwelling as a whole, taking into account the existing structure and any improvements being made as part of the extension project. This method can account for factors like solar gains, upgrades to the existing heating system, windows, and insulation. However, it requires a full set of drawings for both the existing dwelling and the proposed extension.

Our skilled team of SAP-certified energy assessors is dedicated to collaborating with you to guarantee that your project meets the DER/TER requirements for a pass rating.