Building Regulations - Part L & J
A. Part L of the Building Regulations (England And Wales) concerns the conservation of fuel and power in buildings.
The amendments to Part L came into effect from April 1st 2002 and are split into two parts. Part L1 deals with dwellings
and L2 concerns buildings other than dwellings. The regulations cover the issues
of improved insulation and more efficient
heating and lighting systems. In
Scotland the regulations are known as Part J and incorporate some differences
to Part L.
In Part L1 for dwellings there are three methods of compliancethat
can be adopted to meet the new regulations:
- Elemental Method
- Target U-value Method
- Carbon Index Method
The Elemental Method is the most straightforward and is met
by ensuring that all elements of the building(ie. the roof, walls, floor
etc) comply with the U-values shown in the tables below. The U-value measurement
(the measurement of thermal efficiency) must
be less than or equal to the figures
in the tables below. Windows, doors and rooflights have their combined values
averaged out
and their total area should not exceed 25% of the base area of
the building.
U-values for Elemental Method for Dwellings Part L (England & Wales)
Building Element
|
U-value required - W/m2K
|
Walls
Floor
Pitched roof with insulation between joists
Pitched roof with insulation between or over rafters
Flat roof with insulation over rafters
Windows, doors and rooflights
-in wood or PVC frames (area weighted average)
-in metal frames (area weighted average) |
0.35
0.25
0.16
0.20
0.25
2.0
2.2
|
Elemental Method for Dwellings Part J (Scotland)
Building Element
|
U-value required - W/m2K
|
Walls
Floor
Pitched roof with insulation between joists
Pitched roof with insulation between or over rafters
Flat roof with insulation over rafters
Windows, doors and rooflights
-in wood or PVC frames (area weighted average)
-in metal frames (area weighted average) |
0.30
0.25
0.16
0.20
0.25
2.0
2.2
|
These figures are dependent on SEDBUK rating of heating system.
The details
on this website relating to Building Regulation Part L (J for Scotland)are
only an overview, so please contact your local
branch if you have any concerns
or queries at all.
Our expert staff will be able to assist you one-to-one,
either over the phone, in a meeting, or on-site.