28th July 2021
We'll help you work out what type of roof or loft insulation to go for, how much it will cost, if you can get it for free, and how much you could save by insulating your roof.
The type of insulation you should choose will depend on the type of roof you have.
The simplest and cheapest roof insulation is the classic cold loft option. Insulation is placed over and between the wooden joists, above the ceiling of your home's top floor. This is often just called .
It will stop the heat escaping from the living area of your home, but leave the loft space uninsulated. This means it will remain cold in winter and warm up in summer.
It's fairly easy to do as a DIY project, and you can buy loft insulation from most high street DIY stores.
Cold loft insulation is the only type of roof insulation you can apply to have the costs covered by a grant. Click to find out more about insulation grants.
If you can't install cold loft insulation because, for example, you're using your loft as a living space, you will need to consider warm loft insulation.
For a warm loft, you install insulation directly under the roof in the plane of the roof's pitch (slope). Insulation will reduce heat loss and your loft space won't become excessively hot in summer or cold in winter.
It's not as easy as laying rolls of insulation, but it can still be done as a DIY job if you'd rather not pay an installer.
One important point to remember with a warm loft solution is the need for ventilation immediately below the roof tiles. This prevents condensation build up or water getting in through or around the tiles, which could cause the roof structure to rot.
The materials used to insulate under the roof include batts of mineral or glass-wool insulation, held in place by battens of wood attached to and across the rafters. Alternatively, polystyrene slabs (that are sometimes foil-covered) can be fitted. These usually have to be cut to size.
Another option is EPS (expanded polystyrene) squeeze products. These are manufactured in a concertina shape that springs open when they are pushed into place.
Spray foams are mainly professionally installed, but also available as a DIY measure. Spray foam can alternatively be used to provide additional physical strength where a roof is not in the best condition – as it helps hold the structure together. Missing or slipped tiles must be fixed before applying the foam insulation. Find out how much costs and if it's suitable for your home.
There are three types of insulation for flat roofs and a professional should help you to decide which one is best for you.
A good time to insulate a roof is when it's being replaced, although in many cases a roof that is in good condition can be retro-fitted with insulation.
You'll almost always need to use a professional installer to fit your flat roof insulation, and there are no energy grants available to help with the cost. You can use Which? Trusted trader to help you find a recommended, local .
You can also use our Trusted Traders search tool below.