Cavity Wall Insulation for your home

“Up to half of all heat lost in an average house goes straight through the walls. Proper wall insulation can stop up to two thirds of this heat loss”, according to the Government’s energy efficiency division at DEFRA.

Simply speaking, insulation in the walls of your home prevents heat loss in winter, also heat gain in summer, and reduces your energy consumption for heating resulting in:

1. Lower heating bills
2. Lower ‘wear and tear’ on your boiler
3. Reduced Global Warming and Climate Change

For example, a centrally heated home built in the 1970’s without insulation would consume about five times as much as a home built to today’s Building Regulations. If this home had a floor area of 120m2, the gas bill would be about £500 per year, but the same house built to current regulations would cost about £100 per year.

Cavity wall insulation is injected into the cavity between the inner and outer leaves of brickwork that make up the external wall of your property. A technician will do this from the outside of your property. There are a variety of different insulating materials, but they all work in the same way: by combining with the still captive air, the insulation acts as a barrier to heat loss.

It can normally be applied from the outside through small holes, drilled in the wall by technicians. The material is then injected through the holes, filling the cavity. The holes are filled in to make as perfect a match as possible with the existing wall.

This results in the air space (the “cavity”) between the inner and outer masonry skins of your outside walls being filled with insulation. Modern houses (built in the last 10 years or so) have this insulation built-in when the house is constructed, but many older houses do not.

The materials used for cavity wall insulation are mineral wool, urea formaldehyde foam and expanded polystyrene bead. These materials are all resistant to water penetration and will not transmit water across the cavity or from below the level of the damp proof course by capillary action. However, they are not a water vapour barrier and any moisture that collects within the fabric of the building is allowed to disperse harmlessly into the outside atmosphere (provided normal 'breathable' constructional materials have been used). Materials do not affect the fire resistance of the walls; and they are resistant to rot, fungi and vermin.