• MenuMenu
  • Home
Glazed Extension

Extension SAP Assessments

Have you been asked by Building Control to provide a Notional vs Compliant SAP Assessment because your extension has more that 25% glazing and not sure what you need? We can help guide you through the.....

Part L1B of the Building Regulations sets out specific criteria that you are required to comply with when constructing an extension to an existing dwelling. These include include meeting U-value requirements on all new build elements and designing no more than 25% off the extended floor area in glazing.

However, optional approaches with more design flexibility are available. One such approach is to undertake a SAP Assessment to show that the calculated carbon dioxide (CO₂) emission rate from the dwelling with its proposed extension is no greater than that for the dwelling plus a notional extension which is built to the current standard Building Regulations for extensions. New build and renovated elements will still be required to meet the elemental U-value targets.

To meet the Building Regulation requirements, it may be necessary to make additional improvements to the existing dwelling, such as installing extra layers of mineral wool insulation within the loft space. Again, these additional improvements to the building fabric will need to meet the minimum Building Regulation standards.

Conservatories and porches are exempt where the work is at ground level, the floor area is less than 30m2, the heating system does not extend into the conservatory and the external wall and door separating the dwelling and the conservatory is retained.

If you are planning an extension or conservatory or would like further advice and information please do give us a call on 01962 718870.

Why not ask us for a quote?

We have extremely competive pricing, why not get a free non-commital quote.


Ready for a quote?

We have extremely competive pricing, why not get a free non-commital quote. Call us on 01962 718870 or use the link below.


Why choose Sadler Energy for your next construction project?

There must be a reason why our clients keep coming back to us.

On Time

We know you have tight deadlines and last minute hand overs and we do our best to work to them.

On Budget

Our competitive pricing structure means we wont stretch your budget.


We offer all services under one roof, saving you from managing multiple sub-contractors.

Great Ideas

Our staff continue to stay abreast of latest products and will guide you to the most efficient approach.


Switching to us couldnā€™t be easier, and we are sure you will find the way we work a breath of fresh air.

Happy Clients

We strive for happy clients, don't just take our word for it, read our great client reviews.

© 2006 - 2016 Sadler Energy and Environmental Services Ltd.
[Site Map] [Privacy] [Environmental Policy]

SAPs • Code For Sustainable Homes • EPCs • Air Testing
Covering Southern England: Hampshire, Dorset, Sussex, Wiltshire, Berkshire, Surrey and London.


We use cookies to ensure that we give you the best experience on our website. If you continue without changing your settings, we'll assume that you are happy to receive all cookies on the Sadler Energy website. However, if you would like to, you can change your cookie settings at any time.

More Information