Thermal Insulation Regulations
National Building Regulations Approved Document L is concerned with aspects of thermal insulation.
It should be noted that as Document L is subject to ongoing increases in the thermal insulation requirements, this means external walls, roofs and any other external construction will require greater levels of insulation to achieve the required thermal insulation figures. Document L is being used to ensure that the housing stock makes a major contribution to the reduction in mational CO2 output.
Document L covers the following:
L1 - Conservation of fuel and power.
Thermal insulation of the building fabric can be quantified by a figure calculated for a specific construction - a U-value (the thermal resistance).
Consideration of all the thermal resistances of all the elements is taken into account (e.g. in a wall construction with brick, airspace, and wall lining) as well as the bridging of any layer by another material. The lower the U-value, the greater the thermal insulation.
There are standard U-value requirements for dwellings and these are split into separate elements, e.g. roofs, walls, etc.
The British Standards that are most relevant to aspects of thermal insulation including the use of plasterboard and associated products are as follows:
Control of condensation in buildings.
BS8000: Part 8: 1994
Code of practice for plasterboard partitions and dry linings.
BS8212: Part 1: 1995
Code of practice for dry lining and partitioning using gypsum plasterboard.
CIBSE Guide A - Environmental design - this publication gives figures for the thermal properties of building materials structures.
Note: there are regional differences in regulations for Scotland and the Republic of Ireland.