SAP: extensions
As part of Building Control sign-off, all new extensions must comply with Approved Document L1. This Approved Document forms part of the government’s plan to limit carbon emissions and tackle fuel poverty. In most cases the design specification for the extension will surpass the minimum allowable standards and compliance with Approved Document L1 will be straight forward. However, one common area where extensions do not automatically comply concerns the amount of allowable windows, doors and roof lights: referred to as the 25% glazing allowance.
The 25% glazing allowance is equal to 25% of the floor area of the extension plus the area of any openings that are no longer exposed as a result of the extension works. For designs where the proposed area of glazing is in breach of this allowance a SAP calculation can be used to demonstrate compliance and achieve Building Control sign-off. SAP is the government's approved methodology for assessing energy performance in dwellings. By conducting a SAP calculation it is possible to show that features of the design that do not meet the minimum standards of Approved Document L1 (such as the level of glazing) have been compensated for elsewhere in the design.
We can provide you with a SAP assessment to make sure your extension is compliant with Approved Document L1 of the Building Regulations. Using SAP to determine cost effective and practical solutions we can ensure compliance is achieved irrespective of how much glazing is included in the design.
What we do
It is common for projects that we assess to achieve a pass first time. If the extension does not achieve a pass, we will provide solutions to bring it back into compliance. These could include changes to the thermal insulation within the extension, cost effective and practical energy performance improvements to the the existing house, or specifying higher performance glazing within the extension.
Once changes have been agreed we shall provide SAP reports for submission to Building Control.
What the SAP assessor needs
To be able to undertake a SAP calculation we shall need a copy of the Building Regulation drawings for the proposed extension (floor plans, elevation drawings and section drawings) and a copy of the supporting construction notes.
Why choose Achieve Green?
Quick, competitive and accurate SAP calculations.
Comprehensive advice and support to ensure you arrive at the most cost-effective and practical solution to achieve compliance and obtain Building Control sign-off.
One comprehensive fee that includes:
- SAP calculations
- U-value calculations
- All the advice necessary to make sure the extension achieves compliance.
COMPETITIVE
Fast and accurate assessments at a competitive price.
EXPERIENCED
Comprehensive advice and support to ensure you arrive at the most economic and feasible solution to achieve compliance.
QUALIFIED
You can take comfort that the certificates we provide will be accepted as evidence for Building Regulations sign-off.
VALUE
Best quality advice, at a price that offers real value for money.
Testimonials
We are an RIBA Chartered Architectural Practice based on the South Coast, and have used the services of the Achieve Green team in Tunbridge Wells on countless projects over many years, mainly for the preparation of SAP calculations but also energy statements and air pressure testing across a broad range of projects. They have offered us invaluable practical advice on more complex projects to ensure compliance with the ever evolving statutory standards and we have always found them to provide a prompt, efficient, friendly and cost effective service and would not hesitate to recommend them.
Lightbox Architecture Limited
We have found the Achieve Green team to be highly experienced, specialised and competent. Advice is constructive and their approach to projects is strategic, ensuring the most effective solutions are taken forward. The team has a comprehensive understanding of planning requirements and appreciates how these translate into technical and on-site delivery. We highly recommend the team and look forward to working with them on forthcoming projects.
Kitewood Estates Ltd
As a business we have been involved with Achieve Green for a number of years. Their proactive involvement in our projects from design through to completion has enabled us to continually improve the energy efficiency of all our homes. The prompt and efficient service has meant they have become an integral part of our design team.
Panfile Ltd
I have been working with Jonathan and his Achieve Green team in Tunbridge Wells since 2011 on a range of projects from Schools, new build housing to straightforward extensions. They are very knowledgeable and efficient and have provided invaluable input to projects over the years ensuring that as a designer I can put forward the most cost effective solutions to complying with Part L.I always recommend Jonathan if ever anybody is in need of SAP and compliance testing services.
Bradbury Design Ltd