How to insulate your loft

How much will I save?

Heat rises, so insulating your loft is a very good idea – at least 15% of your heating costs might go through your roof if you have no insulation. Fitting loft insulation can save as much as £150-250 every year, and will cost from as little as £80 upwards if you do it yourself. Some financial support may be available depending on where you live and your personal circumstances, and insulation could even be free if you qualify for an ECO grant (see Insulation grants).

Do I need loft insulation?

Even if you have some insulation it may be worth topping it up. The recommended depth now is 270 mm (almost 11 inches), and you may still save £30 a year by adding another layer to what you’ve got. The Energy Saving Trust gives more details on costs, savings and paybacks. If every UK household fitted loft insulation to the recommended thickness it would save 2.7 million tonnes of carbon dioxide each year.

If you already have 80 mm (3 inches) or more loft insulation, increasing the depth to 270 mm is certainly worthwhile, but it might affect your eligibility for special deals or grants. In this case, if you are able, it may be worthwhile fitting it yourself. Check out the range of loft insulation available from B&Q and Wickes.

Most ceiling joists are 100mm deep, so if the space between these is not already filled with insulation, you will need to do that first, then lay another 150 or 170mm over the top at right angles.

Grants

Although loft insulation can be a fairly straightforward DIY job, you may qualify for a grant under the ECO scheme (see Insulation Grants). In any case, the first step is to phone the Energy Saving Advice Service on 0300 123 1234 or Warmer Homes Stafford on 0800 677 1785.

Loft clearance

A common obstacle to installing loft insulation is clearing the loft space of accumulated stuff, whether assorted lumber or treasured possessions. Companies often demand that this is done before they will install the insulation material. However, some installers now offer a loft clearance service as part of a package, although this adds considerably to the installation cost. Alternatively, you may be able to hire someone to do this for you, or if the space contains only a few items, the installer should be able to work around them.

Important points:

  • If you are using mineral wool insulation, wear protective clothing to avoid irritation to your skin and breathing in loose particles.
  • Do not lay insulation under the cold water tank, as the loft space will be much colder, and the water may freeze. You can buy cold water tank insulating jackets to go over the tank.
  • Allow for some ventilation in the loft space – don’t push the insulation tightly into the eaves
  • Don’t forget to insulate the water pipes.
  • Don’t forget to insulate the loft hatch and fit draught strips around the edge.
  • Don’t squash down the insulation by storing things in the loft. If you need to use the loft for storage, perhaps you can use space boards over part of the area and fix raised shelving
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