Building Regulations for loft insulation, cavity wall insulation and the renovation of thermal elements


Loft insulation

Fitting insulation that is at least 250mm thick could cut heat loss by around 30 per cent. Insulation is simply laid over the floor of the loft, between and then over the joists if they are visible.


Protective clothing, gloves and masks should be worn. Care must be taken not to insulate below the cold water tank, if one is present, and not to compress the insulation in tight corners or eaves. Walk boards can then be laid over the joists to provide safe access from the loft hatch to any water tanks (if present).


Loft insulation can be carried out as a DIY task or by a professional installer. There are grants and offers available to help you pay for loft insulation.

Cavity wall insulation

If you have unfilled cavity walls, installing insulation could cut heat loss by over 30 per cent. Filling the gap between the two walls of a house with an insulating material massively decreases the amount of heat which escapes through the walls.


It will help create a more even temperature in your home, help prevent condensation on the walls and ceilings and can also reduce the amount of heat building up inside your home during summer hot spells.

Renovation of Thermal Elements

When you re-render internally or externally, provide a new roof covering, or replace ground or exposed floors, this is now deemed building work for the purposes of conservation of fuel and energy under the Building Regulations. More information is available in the LABC Technical Briefing.