Building Regulations

Recommended U Values for Domestic Buildings. 

Whether it be a new build or retrofit, there are a set of standards thermal insulation need to be adhered to to comply with Building Regulations. These standards are set out by the Government to ensure homes are designed to be energy-efficient and compliant. 

What is a U Value? 

A U-Value is a measure of heat loss in a building element such as a wall, roof or floor. It measures how well parts of a building transfers heat. This means the higher the U value the worse the thermal performance of the building. A Low U-value usually indicates high levels of successful insulation. 

Knowing the U-Value of a building is a useful way of predicting the composite behaviour of an entire building element rather than relying on the individual materials. To calculate the U value of a building element such as a wall, floor or roof, you need to know the build-up of the specific element. The properties of each element are required to calculate the overall u-value as accurately as possible. Use an online U Value calculator to work out the energy efficiency of your home. 

ENGLAND - Current Building Regs 2018

ElementNew BuildExtensionRenovation
WALL0.180.280.3
FLOOR0.130.220.25
PITCHED ROOF – CEILING LEVEL0.130.160.16
PITCHED ROOF – RAFTER LEVEL0.130.180.18
FLAT ROOF0.130.180.18

SCOTLAND - Current Building Regs 2018

ElementNew BuildExtensionRenovation
WALL0.150.170.22
FLOOR0.130.150.18
PITCHED ROOF – CEILING LEVEL0.100.110.15
PITCHED ROOF – RAFTER LEVEL0.100.130.18
FLAT ROOF0.100.130.18

WALES - Current Building Regs 2018

ElementNew BuildExtensionRenovation
WALL0.160.210.3
FLOOR0.110.180.25
PITCHED ROOF – CEILING LEVEL0.110.150.16
PITCHED ROOF – RAFTER LEVEL0.110.150.18
FLAT ROOF0.110.150.18