Approved Document L1B provides guidance on complying with the requirements of Regulation L1 dealing with the conservation of fuel and power. It is one of four Part L Approved Documents and deals specifically with work to existing dwellings.
The Herts Building Control Technical Forum (HTF) has produced this guide to clarify the document’s contents in relation to the design of extensions to dwelling houses. A separate guide is available dealing with schemes involving a change of use to form a dwelling. See guide ‘Change of Use to Form a Dwelling’.
