What is cavity wall insulation?

If the external walls of your house are made of two layers with a small gap or 'cavity' between them, they are 'cavity walls'. Generally, most houses built after 1920 are constructed this way.

Cavity wall insulation is used to reduce heat loss through this cavity wall by filling the space with a porous material. This immobilises the air within the cavity (air is still the actual insulator), preventing convection and heat loss. Cavity wall insulation can substantially reduce space heating costs.

The vast majority of houses built in the last ten years will have had the cavity walls filled during construction. There are many types of building insulation materials on offer each with various advantages. Glass fibre wool or rock wool panels are widely used.

For existing buildings whose cavities were not insulated during construction, a fibrous material such as cellulose insulation or glass wool is blown into the cavity through suitably drilled holes until it fills the entire wall space. Foam can also be used for this purpose.

Cavity wall insulation is so cost effective that it will soon pay for itself (it is estimated that the average payback time for cavity wall insulation is just two years). The better insulated your home, the less energy you need to keep it warm - and the more money you'll save.

There are grants available under the Carbon Emissions Reduction Target (CERT) to contribute towards the outlay cost.

Once only of interest to a small minority, green is the new black as far as self-building is concerned.

With the effects of global warming becoming increasingly apparent, more and more people are seeking greener ways to provide the energy needed to run a home.

Whether it's solar panels, heat pumps, high specification glazing or eco-friendly wool insulation in the loft space, there is little doubt that it is self-builders who are setting the standards for a greener future for the building industry and the way we live our lives.

Underfloor heating for example, has been available for years but, by and large, the self build market has been the industry's bread and butter - with large scale property developers still opting for standard, less efficient radiators.

But it's not all about saving the planet. Incorporating green ideas into a home can lead to reduced running costs and save you money in the medium to long term too. And when you come to sell your home in the future, you can guarantee that the greener it is the more attractive it will be to prospective buyers.

There is a greater sense of purpose from the government to promote green alternatives too with a stick and carrot approach in place.

Building regulations now demand far better energy efficiency while government grants are available for loft insulation right through to solar panels, heat pumps, wind turbines and other microgeneration technologies.

Self-builders are leading the way as far as greener homes are concerned and greenselfbuild.co.uk will be with you every step of the way towards a greener future for you, your family and the wider community.