Part L1B - Material Change of Use

Part L1B - Material Change of Use

We provide SAP calculations for dwellings that are created by material change of use, in line with Building Regulations Part L1B. Our assessors are fully qualified and accredited to issue an L1B material change of use reports that demonstrate compliance with the Building Regulations.

A part L1B Material Change of Use guidance covers the following, after change:

• Building is used as a dwelling where it has not been previously, 
• Building contains a flat, where it has not been previously, 
• Building which contains at least one dwelling, contains now greater or lesser number of dwellings.

A SAP calculation can be used for dwellings created by a change of use and compared to the notional dwellings built to the Building Regulations standards. If calculated carbon dioxide (CO2) emission rates from the dwelling are lower compared to emission rates of the notional dwelling, they achieve compliance with the regulations. 

A good provision would be to use the fuel that have associated the lowest carbon emissions; for example: if the building that is going to house five flats has mains gas supply, then all the flats should be using mains gas, instead of electricity. When comparing the actual flats to notional ones, the latter ones are going to use mains gas and therefore have associated much lower carbon emissions (and therefore flats won’t comply with building regulations standards to achieve lower emission rates). 

There are also different thresholds for new elements and retained upgraded thermal elements. A new cavity wall has to achieve a U-value of 0.28 W/m2K, the retained one on the other hand only 0.55 W/m2K.

Choosing Ashby Energy Assessors means you will get specialist advice throughout the project, along with practical solutions. Our professional reports contain all the information required by building control to ensure you can continue with your project without hesitation.