Building Regulations Part L1B
Overglazed Extensions
Our fully certified and accredited assessors provide SAP calculations for Overglazed extensions using software packages such as JPA Technical to complete SAP calculations in line with Regulations Part L1B. This will determine if the excess glazing will increase the amount of carbon emission of the property or not.
Building Regulations Part L1B permits glazing in the proposed extension to be up to 25% of the floor area of the extension plus the total area of the openings no longer exposed. Compliance is determined by comparing the proposed extension to the defined glazing limit. If the proposed extension exceeds the defined glazing limit it is classed as an "overglazed extension" and would require a calculation to justify the excessive amount of glazing.
The most flexible method of calculation is known as the "whole dwelling calculation method" and incorporates great flexibility permitting revisions to be completed quickly.
Reasonable provision for newly constructed thermal elements such as those constructed as part of the extension would be to meet the below standards.
1- wall U-Value of 0.28W/m2K
2- floor U-Value of 0.22W/m2K
3-windows and roof lights with U- Value of 1.60W/m2K
4-glazed doors with U-Value of 1.80W/m2K
5-pitched roof insulated at ceiling with U-Value of 0.16W/m2K
6- pitched roof insulated at sloping ceiling and flat roof with U-Value of 0.18W/m2K
Why Choose Us
Choosing Your Space means you you get friendly, fully trained, certified and accredited assessors who work with state of the art software packages such as JPA Technical. We keep you fully informed until the assessment is successful and our reports contain the building control required information ensuring a speedy progression of your development.
Why Choose Us.
Choosing Your Space means you get friendly, fully trained, certified and accredited assessors who work with BRE approved software packages such as JPA Designer. We keep you fully informed until the assessment is successful and our reports contain Building Control required information ensuring a speedy progression of your development.
