How to
Overcome Challenges


You probably know about the necessity of SAP calculations and the role they play in the design of new builds, and you might even know how best to avoid things going wrong with them. But what’s the deal with extensions? Well, these present another big hurdle. But, don’t despair. You’re in safe hands, and we’re going to walk you through it.

The Challenge

SAP calculations for extensions fall under Part L1b of the Building Regulations, which provide more-than-annoying limitations for planning. Chances are, anybody having an extension will be looking for lots of nice natural light, right? Who doesn’t like natural light? For that, you’re going to be thinking of lots of lovely glazing. 

Here’s where things get tricky. As glazing and openings lose more heat than walls and roofs, the building regs require that areas of new glazing should account for no more than 25% of new floor area. And yep, the majority of extension designs will propose more than this. So, what do you do?

Helping you Comply

There are a few ways accredited assessors like us kind folk at Purple Energy can help you get that luminous extension you, or your clients, so desire. Our SAP calculations can be designed to demonstrate how even with large areas of glazing, your extension complies with the building regs. And no, it doesn’t require any stealthy passing of cash underneath tables.

By upgrading other elements of your build we can mitigate the negative impact of large expanses of glass. We can also demonstrate how your extra glazing can provide useful solar gains, as well as taking other measures down the eco route. Long story short, whichever way you want to look at it, we can sort it so you have your extension the way you want it.

Cut to the Chase

SAP Calculations for extensions can be tricky. Luckily enough, we know how to get around them to ensure you can have as much glazing as you’d like but still pass the test. As ever with SAPs though, it’s crucial to start early. If you’re thinking about an extension already, it’s about time to get in touch

If there is anything you feel unclear about or you simply want to speak to one of our team members, don’t hesitate to give our office a call.