The measure of heat loss through the fabric of a building is expressed as a U-value with limiting values set out in the Building Regulations.

The Building Regulations set out requirements for specific aspects of building design and construction. Regulation 26 of the building regulations states that “Where a building is erected, it shall not exceed the target CO2 emission rate for the building…”, and Schedule 1 – Part L Conservation of fuel and power states that provision for conservation of fuel and power shall be made by limiting heat gain and losses and providing building service which are efficient, have effective controls and are properly commissioned and that information is provided so that the building can be operated efficiently.

All new homes must produce 31% less carbon emissions than the old 2013 Part L Regulations. New homes will be assessed under a new Standard Assessement Proceedure (SAP) called SAP10. Builders are encouraged to meet notional dwelling targets for energy efficiency which are measured in u-values. The minimum u-value for floors is set at 0.13w/m²K. Note; this is the minimum therefore if the u-value of another element within the building is poor, then the floor u-value may need to be improved to a lower value. Full guidance of this can be given from SAP Assessors or by visiting: Guildance To 2021 Part L Regulations

A = 75% Full Panel / 25% Half Panel Installation
B = 50% Full Panel /205% Half Panel Installation