How to buy loft insulation Fitting blanket insulation
Blanket insulation is fairly easy to install yourself
Blanket insulation is the most common type of insulation and is sold in rolls, which are laid down between the flooring joists in your loft.
Fitting blanket insulation
Rolls of blanket insulation come in various different widths to match to your loft, so start by measuring the distance between joists and buying the nearest size.
Ideally it should fit neatly between the joists. To calculate the right amount, measure the length of the floor space to be covered. Don't stretch or tear blanket insulation – use scissors if it needs to be cut.
Unroll the insulation blanket and lay it flat between loft joists. If possible add a further layer of blanket insulation across both the joists and the lower layer of insulation. Be careful not to squash the insulation down.
If you want to use your loft for storage, you can place boards down backed with further insulation over the top, or you may need to raise the level of the floor to ensure that the 270mm recommended insulation is achieved. If you're not sure of the best option, contact an installer for a professional opinion.
DIY or get a professional?
Confident DIYers should be able to lay this type of insulation relatively easily themselves – but you should always refer to the manufacturer's instructions to ensure you're fitting it correctly and getting the most out of your insulation.
Many insulation grants and offers are available from the government, councils and energy companies – and the discounted materials and installation rates on offer mean that, in some cases, getting a professional to fit your insulation could be cheaper than doing it yourself. Consult the EST’s grants and offers database to see what's available in your area.
Before installing insulation
Each type of insulation is fitted differently, but most blanket insulation can be installed as a DIY project. Whatever type of insulation you choose, you'll need to make a few preparations before you start.
Clearing your loft
Even if you’re getting a professional loft insulation installer to complete the work for you, you’ll usually need to clear your loft before they arrive.
When you insulate your loft you'll need to insulate pipes and tanks too
Wiring
Wiring needs to be dealt with safely. Wires should be kept above the insulation but not stretched if they don’t comfortably reach. An electrician will be able to re-route any problematic wiring – see our guide to hiring an electrician.
Pipes and tanks
Pipework and tanks in the loft should also be insulated correctly, as less heat will be escaping into the loft and protecting pipes from freezing.
If in doubt
Insulation must be installed following the manufacturer's instructions to achieve the full benefit. If you're unsure about any aspect of insulating your loft, you should contact a professional insulation fitter.
Which? Local
Which? Local can help you find loft insulation installers in your area recommended by other Which? members.
- Find out about other types of loft insulation
- Have you considered cavity wall or solid wall insulation
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