England & Wales Building Regulations: Part L1B conservation of fuel and power: Existing dwellings - A summary of requirements (Version 2)

TRADA image

Approved Document L1B (ADL1B) seeks to improve the energy efficiency of existing dwellings as and when they are renovated, extended or altered. Because we are only adding a small percentage to our housing stock each year, improvements are necessary to existing housing if we are to make an appreciable improvement to the energy requirements of the nation's dwellings.

This Construction Briefing is only concerned with the requirements of Part L1B, and gives readers an overview of the requirements, particularly those related to thermal elements such as external walls, floors, roof, windows and doors, and the alteration of materials.


  • Definitions
  • Thermal elements - external walls, floor, roofs, windows and doors
    • General
    • Renovation
    • Material alteration
    • Material change of use
    • Extension
  • Energy efficiency of controlled services (eg heating, lighting etc)
  • Feasibility
  • Design flexibility
  • Historic buildings

Suggested Reading

Dynamic response of timber flitch beamsnavigation-arrow

Through experimental analysis, James Norman, Joel Ross, Robbie Kirkbride and Toby Hill-Smith outline the damping exhibited in these complex beams.


Article from Timber 2017 Industry Yearbook

01/03/2017 |  Magazine Article  

A motorway service station - but not as we know itnavigation-arrow

Exposed timber structures sympathetic to their rural surroundings are at the heart of a recently opened motorway service station in Gloucester.


Article from Timber 2018 Industry Yearbook

14/05/2018 |  Magazine Article  

Joinery: natural retreatnavigation-arrow

Outright winner of the prestigious Wood Awards 2017, the Coastal House is a showcase for the many uses of timber and some fine joinery.


Article from Timber 2018 Industry Yearbook

15/05/2018 |  Magazine Article