SAP Calculations for Extensions

We all want lots of light – and we all like lots of lovely glazing right? It is likely that you will need to provide SAP Calculations for extensions if your proposal includes large areas of glazing.

SAP Calculations for Extensions

Building regs require that areas of new glazing should account for no more than 25% of new floor area.

Of course, many extension designs will propose more than this, and therefore will not comply against this rule.

We can help you overcome this hurdle easily and quickly.

SAP Calculations for Extensions – How Do They Work?

Glazing and openings lose more heat than walls and roofs, which is why the building regs set the 25% limit. However by upgrading or over compensating in construction of other elements, or perhaps demonstrating additional, useful solar gains by virtue of that extra glazing, the negative impact of larger expanses of glass can be removed.

There are further options to upgrade the existing property – especially useful if the existing dwelling is receiving a make-over too. We can guide you through all the options.

Many change of use schemes will also be subject to SAP regulations, like flat conversions or commercial-to-residential conversions.

SAP Calculations For Extensions – Our Speciality

We carry out a large volume of SAP Calculations for extensions on a daily basis, and can provide you with all the help and guidance you need. We’ve helped many hundreds of homeowners all over the country and it is extremely rare that we do not find a solution – without having to change your plans.

We can even deal with your Building Control Officer, understand what is required, and take care of everything – Easy!

Want to Discuss your Extension or Renovation Project?

Just give us a call on 01202 280062 or send us your enquiry - we’ll get straight back to you.


We have used the team at Build Energy to assist us with the complex calculations and testing required to meet current building regulations......we have found them to be a valuable one stop source for all projects - they are extremely professional, reliable and competitive with regard to cost......we would not hesitate to recommend their services

Nicholas Lavidge – Director, Refurbishment for London