The average cost of loft
insulation is around £350
Pricing guides

How much does loft insulation cost?

The loft insulation costs in this article are correct as of 2022

Insulating your loft or attic is a great way to help make your home more energy efficient, helping to retain heat and lowering your heating bills.

The cost spent on insulation can often be recouped by these savings in a couple of years, so it is worth considering for any home without it.

Before you start your project, we’ve put together this guide to help show the typical range of loft insulation costs, so you know what to expect.

Loft insulation

It is recommended that loft insulation be at least 270mm thick, and this can be achieved with a variety of materials.

Loft insulation can be made from fibreglass, mineral wool, sheep’s wool, cellulose, and other materials, and most commonly comes packaged as a roll which can simply be laid out between and over the joists.

These rolls can cost as little as £20 or so, for a roll which will cover around 8 metres squared. Depending on the size of your home, and of its loft, this means can insulate the loft yourself for less than £100.


However, hiring a professional insulation specialist is the best way to guarantee a good job, and to take care of all the issues that come along with it.

Factoring in the cost of the materials, and the labour involved - typically less than a day’s work - and the usual cost for insulating a loft with basic blanket insulation is between £300 and £400 depending on the size of the loft.

Another method for insulating a loft include loose-fill insulation, which uses a material like cork or other materials similar to those found in blanket insulation, which can be spread in the area between joists. Prices for this are usually similar to blanket insulation. 

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Spray foam insulation costs

As well as simple rolls of lagging or loose-fill insulation, another popular alternative for loft insulation is spray foam or blown-foam insulation, where a layer of foam is sprayed from a specialist machine over the area to be insulated.

This needs a professional to install, but is handy for areas where access is difficult and is quick to do.

Prices are not too dissimilar to other types of loft insulation, but may be slightly higher due to the dedicated tools required.


Other costs to consider

There are a couple of complications with loft insulation that can add to the overall price of a project, though they typically should not be a significant extra expense.

For example, because loft insulation retains heat downstairs, it means the resulting temperature in the loft itself will be lower, which can cause problems when external temperatures are very low and particularly if they drop below freezing.

For this reason, any pipes in the loft will have to be insulated as well, which adds a small amount of extra work.


Another example is if you wish to use your loft for storage, in which case you will need to add boards above the joists. These joists cannot sit on top of the insulation material, as compressing it removes all the efficiency from the insulation, so you will need boards with a built-in insulation layer.

These are usually more expensive than blanket insulation will be, though depending on how much space you want to board, you may not need much.

If you have electrical wiring running across your joists, this may have to be re-routed depending on the materials used - if an electrician is needed, this can add a lot to the project, with electricians typically charging around £40 per hour.

Similarly, if you have issues with damp, or leaks or holes in the roof which could allow water in which might damage the insulation, these issues will all have to be addressed before insulating becomes viable. The cost for these can vary widely depending on what needs to be done. 

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