Loft insulation installers

What is loft insulation?

We lay the first layer to the depth of the joists, usually 100 mm, so it fills each bay edge to edge with no gaps. The second layer goes across the joists at right angles, which covers the timber and stops it acting as a cold bridge. The finished depth sits at 270 mm or more, the depth the Energy Saving Trust recommends.

Is it right for your loft?

You can see the joists or the plasterboard between them
Upstairs rooms are cold even with the heating on
Snow and frost melt off your roof before your neighbours'
You are selling or letting and the EPC flags the roof

How we do it

We check the loft: access, wiring, the water tank, ventilation at the eaves and any damp.
We lay crawl boards, clear a route and protect the landing below the hatch.
The first layer goes between the joists, cut neatly around cables, pipes and light fittings.
The cross layer goes over the top, kept back from the eaves so air can still move.
We fit covers over downlights, lift cables above the insulation where we can, jacket the tank and lag the pipes.
You get photos of the finished loft and a note of the depth laid.

What is included

Mineral wool to 270 to 300 mm across the whole loft floor
Eaves kept clear, with ventilation trays where air could be blocked
Cables lifted clear of the insulation where possible
Tank jacket and pipe lagging in the loft
Area under the cold water tank left clear so it cannot freeze
Waste packaging removed

Worth knowing

Boarding laid straight onto the joists squashes the insulation and undoes most of its value. If you need storage, we raise the boards on loft legs instead. If the loft has damp, a leaking roof or bare wiring, that gets sorted first.

How much does loft insulation cost?

£495 to £745Terraced house, average loft, from bare joists. Free survey and a fixed written quote before any work.

Home	Essential	Recommended	Natural fibre
Top-floor flat	£495 to £845	£795 to £1,295	£1,345 to £2,095
Terraced house	£495 to £745	£745 to £1,195	£1,195 to £1,895
Semi-detached or end-terrace	£545 to £945	£845 to £1,395	£1,495 to £2,295
Detached house	£745 to £1,245	£1,095 to £1,745	£1,895 to £2,945
Bungalow	£895 to £1,445	£1,245 to £1,945	£2,195 to £3,345

Average loft with little or no insulation. Every tier includes a tank jacket and pipe lagging. Recommended adds 300 mm and an insulated hatch. Natural fibre uses sheep's wool with the hatch.

Installing insulation in a home is zero-rated for VAT until 31 March 2027 and 5% after that, under HMRC's rules for energy-saving materials (notice 708/6).

Work out a guide price for your loft or see every price.

Do the rules differ across the UK?

Yes, a little. Building regulations and funding schemes are set separately in each nation. Here is the short version; each area page has the detail.

Nation	Building rules	Funding to check
England	Approved Document L; insulation alone is not usually notified	ECO4 to 31 Dec 2026; Warm Homes Plan and Warm Homes: Local Grant
Wales	Welsh Approved Document L; conversions need building control	Warm Homes Nest; ECO4 to 31 Dec 2026
Scotland	No building warrant normally needed; standards still apply	Home Energy Scotland grant and loan; Warmer Homes Scotland
Northern Ireland	NI Building Regulations (Technical Booklet F1); check with council building control	Affordable Warmth Scheme; NISEP

Questions about loft insulation

How long does it take to insulate a loft?

Most lofts in houses take a single day. A large bungalow loft, a loft that needs clearing first or one with awkward access can run into a second day.

Do I need to empty my loft first?

The floor needs to be clear for the insulation to go down. If moving things yourself is difficult, tell us at the survey and we can price clearing and putting items back on raised boarding.

Will loft insulation make my loft colder?

Yes, and that is expected. The insulation keeps the heat in the rooms below, so the loft above runs closer to the outdoor temperature. That is why pipes and the tank are lagged as part of the job.

How deep should loft insulation be?

The Energy Saving Trust recommends at least 270 mm of mineral wool, and that is the depth we install as standard. Building regulations also set an energy standard for the roof when a loft is insulated. It differs between England, Wales, Scotland and Northern Ireland, so we confirm the target for your address on the quote.

Can you insulate around downlights?

Recessed downlights need clearance or a fire-rated cover so they do not overheat. We fit covers where needed and leave a clear zone around fittings that cannot be covered.

Does loft insulation need building control approval?

On its own it usually does not, but the work still has to meet the energy standard. The rules differ across England, Wales, Scotland and Northern Ireland, so we confirm the position for your address on the quote.

Where we provide loft insulation

Wales

Scotland

Northern Ireland

Often booked with it

Sources, checked October 2026: Energy Saving Trust: roof and loft insulation; Which?: loft insulation costs and savings; LABC: building regulation requirements for loft insulation; GOV.UK: extending the ECO4 end date, government response.