What is a “Highly Glazed Extension Calculation” or an “Area Weighted Average U-value Calculation”?
Where the proposed amount of glazing in an extension is greater than 25% of the new floor area, then Building Control will ask for a “Highly Glazed Extension Calculation” or an “Area Weighted Average U-value Calculation”.
We will model the extension in our software and can lower or raise the u-values in the floors, walls, roof and glazing until we come to an overall compliant average u-value.
If we cannot prove compliance feasibly with the above method, then we will calculate the extension in Full SAP software as a whole house calculation.
What information do we need from you?
- Floor plans, sections & elevations for the existing dwelling & the new extension (please contact us if this is an issue).
- Orientation e.g. site plan/location plan.
- Construction specification of floors, walls and roofs of the new extension, and basic details of the existing part of the house.
- Specification for all windows.
- Primary & secondary heating systems.
- Renewable technology (if any).
How much will it cost?
Area Weighted U-value Calculation = From £70
Whole House SAP = From £140
Email: office@SAPsAndMore.co.uk or you can also submit your documents through our submission form here.
What is included?
- All the relevant SAP documentation required for Building Control and compliance with the Building Regulations.
- Additional necessary “feasible, affordable and common sense” recommendations to ensure a pass is achieved.
- U-value calculations for submission to Building Control and the Architect and Contractor.
- Elmhurst Accredited Assessors and Engineers.
- Comprehensive advice and support throughout the whole project.
- Quick turnaround.
