Loft Insulation Cost: 2026 Prices Per m2 UK

Heat rises, and in an uninsulated home a large share of it goes straight through the ceiling and out of the roof. Loft insulation is one of the cheapest and simplest ways to stop that. It is a quick job, it lasts for decades, and on a home with no insulation at all, it can pay for itself within a few years.

In 2026, insulating a loft with basic quilt insulation costs around £725 on average, according to Checkatrade. A terraced house can come in nearer £650, and a detached house or bungalow can be over £1,200. If you are handy and your loft is easy to get into, doing it yourself cuts the bill to the cost of materials.

This guide explains what you will pay by material and house type, what affects the price, whether you can still get a grant, and how much you can expect to save.

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Prices

Here are typical UK prices for 2026. Prices for whole jobs include materials and labour. Prices per m² are for materials only unless stated.

Checked October 2026: Checkatrade, How much does loft insulation cost in 2026 (updated July 2026).

By house type

The size of the loft is the biggest driver of price, so the type of house is a reasonable shortcut:

Bungalows cost as much as detached houses because the whole floor area sits under the roof, so the loft is large relative to the number of rooms.

Working out your own price

To estimate a job from scratch:

1. Measure the loft floor area: length × width of the house, roughly.
2. Multiply by the material price per m².
3. Add labour. Most straightforward lofts take less than a day, so budget for one day at around £250.
4. Add extras such as pipe lagging, tank insulation or boarding.

Example: a 40m² loft insulated with two layers of quilt: 40 × £10 = £400 materials, plus £250 labour, gives about £650 before any extras. That lines up with the typical terraced and semi figures above.

Materials

The material you choose affects cost, performance and how much space you lose. Here are the main options.

Quilt (mineral wool or glass wool)

Rolls of mineral wool or glass wool are the default for UK lofts. They are laid between the ceiling joists, then a second layer is laid across the joists to reach the recommended depth. At around £10 per m² for materials, quilt is the cheapest way to insulate a standard loft.

Wear gloves, long sleeves and a mask when handling it, because the fibres irritate skin and lungs.

Loose fill

Loose fill insulation, often made from recycled cellulose or mineral wool, is poured or blown between the joists. It is useful for topping up existing insulation and for awkward spaces that rolls cannot reach. Materials cost around £12 per m².

Rigid boards (PIR)

Rigid PIR boards give more insulation for a given thickness than quilt. They are mainly used between rafters when you want to insulate the roof slope rather than the floor of the loft, for example when the loft is used as a room. At around £35 per m² for materials, they cost much more than quilt.

Spray foam

Spray foam is sprayed onto the underside of the roof. It costs around £37 per m² for materials. It has become controversial, because poorly installed spray foam can trap moisture against roof timbers and hide their condition from surveyors. Some lenders and surveyors are wary of it, which can make a home harder to sell or remortgage. If you are considering it, get independent advice and make sure the installer follows current industry guidance.

Thermal foil

Multi layer reflective foil is thin and costs around £14 per m². It is usually used alongside other insulation rather than on its own.

How deep should loft insulation be?

The recommended depth for mineral wool is 270mm. Many older homes have only 100mm or less, laid decades ago. If you can see the tops of your joists, you almost certainly have less than the recommended depth.

Cold loft vs warm loft

There are two ways to insulate a roof space:

Insulating the floor of the loft keeps the house below warm but leaves the loft itself cold. That is the cheapest approach and the one most people need. If you have converted the loft or plan to, you insulate the roof slope instead, which costs more and needs careful ventilation detailing.

Grants

Grant support for loft insulation has changed a lot recently. Here is the position as of October 2026:

Checked October 2026: GOV.UK and Ofgem pages on the Great British Insulation Scheme, the government response on extending ECO4, and GOV.UK guidance on the Warm Homes: Local Grant.

Warm Homes: Local Grant

The Warm Homes: Local Grant can fund insulation, including loft insulation, for eligible households in England. To qualify, the home generally needs an Energy Performance Certificate rating of D to G, and the household usually needs an income of £36,000 or less, qualifying benefits, or to live in an eligible low income area. Funding is delivered by councils, so availability varies and some councils have already allocated their budget for 2026/27. Contact your council to check.

Scotland, Wales and Northern Ireland run their own schemes. Check the government energy advice service for your nation.

Be wary of cold calls

Since grant schemes have changed, some firms still cold call offering "free government insulation". Do not agree to anything on the doorstep. Check any scheme on GOV.UK and with your council before letting anyone into your loft.

DIY vs pro

Loft insulation is one of the few energy upgrades that many homeowners can do themselves.

When DIY makes sense

• The loft has a proper hatch and enough headroom to move around.
• The joists are regularly spaced and in good condition.
• There is no sign of damp, rot or pests.
• There are no wiring problems or old cables in poor condition.
• You are comfortable working in a confined space.

A DIY job on a 40m² loft might cost around £400 in quilt rolls, against about £650 to £825 for a professional installation. The saving is real but modest, so weigh it against the time and the unpleasantness of the job.

When to call a professional

• The loft has very little headroom or awkward access.
• You want loose fill blown in.
• You are insulating a roof slope or a converted loft.
• You need wiring moved or the water tank and pipes insulated.
• There is any sign of damp or condensation.

Professionals usually finish a standard loft in less than a day, and they will often lag pipes and tanks at the same time.

Safety tips for DIY

• Only stand or kneel on joists or boards, never on the ceiling plasterboard between them.
• Wear gloves, goggles, a mask and long sleeves.
• Do not cover recessed light fittings unless they are rated for it. Use covers designed for the purpose.
• Do not cover electrical cables tightly, as they can overheat. Lift them above the insulation where possible.
• Leave gaps at the eaves so air can circulate, or the roof timbers may suffer from condensation.
• Insulate the loft hatch and fit draught strips around it.

Savings

The savings depend on how much insulation you have now. The Energy Saving Trust's figures for a gas heated semi-detached home in Great Britain, using July 2026 fuel prices, show:

Checked October 2026: Energy Saving Trust figures, as reported by Which? and the HomeOwners Alliance, based on July 2026 fuel prices.

That table tells you something important. Insulating an empty loft pays back in a few years. Topping up a loft that already has a reasonable layer saves much less, so it can take decades to pay back on money alone, although it still makes the house more comfortable.

Payback example

A semi-detached house with no loft insulation pays £825 to have 270mm installed and saves about £190 a year. Payback is around four and a half years, and the insulation should last for decades.

Signs your loft needs more insulation

You do not need a survey to find out whether your loft is under insulated. A quick look with a torch will usually tell you. Watch for:

• Visible joists. If the tops of the joists show above the insulation, you have less than about 100mm, well short of the 270mm recommended.
• Patchy coverage. Gaps around the hatch, the eaves or the water tank let heat escape.
• Squashed insulation. Boxes stored directly on the insulation flatten it and reduce its performance.
• Snow melting fast. In winter, if snow melts on your roof well before it melts on neighbouring roofs, heat is escaping through it.
• Cold upstairs rooms. Bedrooms that never feel warm, even with the heating on, can point to a poorly insulated loft.
• High heating bills compared with similar homes.

Preparing your loft

A little preparation makes the job quicker and cheaper, whether you do it yourself or pay a professional.

1. Clear the space. Move stored items out, or at least to one side. Installers usually charge extra if they have to clear a loft first.
2. Check for damp and pests. Look for stains on timbers, droppings or chewed cables. Deal with these before insulating.
3. Check the wiring. Old rubber or fabric covered cable should be inspected by an electrician before it is buried in insulation.
4. Find the light fittings. Note where downlights come through the ceiling so they can be protected.
5. Plan access. Make sure the hatch is big enough for rolls of insulation and that there is a safe way up.

What a professional installation looks like

On the day, a good installer will:

• Lay protective sheets on the landing below the hatch
• Check the joists, wiring and ventilation
• Lay the first layer of quilt between the joists, fitting it snugly without squashing it
• Lay the second layer across the joists to reach the full depth
• Keep insulation back from the eaves, or fit eaves vents, so air can circulate
• Insulate the water tank and pipes if asked, but leave the area directly beneath the tank uninsulated so the warmth from the house helps stop the tank freezing
• Insulate and draught strip the hatch
• Take away packaging and any old insulation if this was agreed

Ask for a simple written note of what was installed and to what depth. It is useful when you sell the house or if an Energy Performance Certificate is done later.

Common problems to avoid

• Blocking ventilation at the eaves, which can lead to condensation and rot.
• Burying cables tightly, which can make them run hot.
• Covering downlights that are not rated for contact with insulation.
• Forgetting the hatch, which can leave a large cold spot right in the middle of the landing.
• Squashing insulation under storage boards laid straight on the joists.
• Insulating over damp timbers, which hides a problem that will only get worse.

Loft boarding and storage

If you use your loft for storage, laying boards straight on the joists over insulation squashes it and cuts its performance. The answer is to raise the boards on loft legs so the full depth of insulation sits underneath. Loft boarding costs around £55 per m² fitted, according to Checkatrade. Our loft boarding guide explains the options.

Ventilation and condensation

Insulating the loft floor makes the loft itself colder, which can increase the risk of condensation on the underside of the roof. To prevent this:

• Keep the eaves clear so air can flow in and out.
• Fit vents if the roof has no natural ventilation.
• Seal gaps around pipes, cables and the hatch so warm, moist air from the house does not leak into the loft.
• Make sure bathroom and kitchen extractor fans vent outside, not into the loft.

If you see damp patches, mould or water droplets on the roof timbers, get it looked at before insulating.

Other insulation to consider

Loft insulation works best as part of a wider plan. If your home has cavity walls, filling them can save even more. Our cavity wall insulation guide covers costs and suitability. For solid walled homes, see our guide to external wall insulation.

FAQs

How long does loft insulation last?

Mineral wool insulation can last for decades if it stays dry and is not squashed. Check it now and then, especially after any work in the loft.

Can I put new insulation on top of old insulation?

Yes, as long as the old insulation is dry and in reasonable condition. Lay the new layer across the joists at right angles to the old one.

How long does it take to insulate a loft?

Most professionals finish a standard loft in less than a day. A DIY job might take a weekend.

Does loft insulation need building regulations approval?

Topping up loft insulation does not normally need approval. Work on a roof slope as part of a renovation or conversion may need to meet building regulations.

Will loft insulation help in summer?

Yes. It slows heat coming in through the roof as well as heat going out, so upstairs rooms stay cooler.

Is there a grant for loft insulation in 2026?

The main options are ECO4 (closing on 31 December 2026, with limited new applications) and the Warm Homes: Local Grant through councils in England. The Great British Insulation Scheme closed on 31 March 2026.

Get quotes

Ask for at least three quotes, and give each installer the same details: your loft size, the existing insulation depth, access to the hatch, and whether you want boards, pipe lagging or tank insulation. Ask what product and depth they will use and whether they will clear and dispose of old insulation.

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