How to buy loft insulation Installing blown insulation

Blown fibre insulation

You'll need to employ a professional to install blown-fibre insulation in your loft

In most cases you’ll need to hire a professional to install blown insulation, as it needs to be blown into place with specialist equipment.

Fitting blown-fibre insulation

With this type of insulation, mineral fibres are evenly blown and spread between the joists in your loft using specialist industrial equipment – it's a fairly quick job for a professional to do, and works well in lofts where the use of blanket insulation isn't suitable, or if your joists are obstructed.

Which? Trusted Traders can help you find recommended loft insulation installers, as well as electricians and plumbers, in your area.

Before getting blown-fibre insulation installed

Whatever type of insulation you choose, you'll need to make a few preparations before you start – ask your installer if they have any particular requirements.

Clearing your loft

You’ll need to clear your loft before your professional installer arrives, unless you've agreed beforehand that clearing your loft is part of the work.


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.

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.

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