Castleton Castleton Energy Assessments Energy Assessments

At Castleton Energy Assessments we are highly experienced in the preparation of SAP calculations for domestic extensions.

Building Regulations compliance is now more challenging than ever for designers and architects, and it is very important to consider energy efficiency early in the design process.

The trend nowadays is for domestic extensions to contain large areas of glass, which is a less effective insulator than brickwork. If the glazed area exceeds 25% of the extension floor area, the Building Control Officer will require a SAP calculation to show that the energy lost through the glazing is compensated for by improved insulation elsewhere.

We are very experienced in this kind of work and we are well placed to help you ensure that your extension complies with Part L of the Building Regulations.

It is a very high-risk strategy to leave the SAP calculation until the building is complete; if the results aren’t favourable then the re-work required can be very expensive, so please let us do the calculations before anyone starts digging the foundations!

Call us now to discuss your project and to hear how we can help.

Telephone 01633 681006 or email

See more detail about how the SAP process works