London & South-East England

Loft & Roof Insulation

Loft and roof insulation is the cheapest, fastest insulation upgrade most homes can make — and usually the one with the quickest payback. Around a quarter of a typical home's heat escapes through the roof, so topping up to the current 270mm standard, or installing a warm-roof system, makes an immediate difference to comfort and bills.

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PAS2030-19 CertifiedTrustMark ApprovedOwn trained team

Is Loft right for your home?

Homes with under 270mm of existing loft insulation (most pre-2000 builds)
Cold lofts used for storage — quick, low-cost top-ups
Converted or room-in-roof spaces needing rafter-line insulation
Properties with flat-roof extensions losing heat
Anyone wanting the fastest-payback measure to start with

What is loft & roof insulation?

There are three jobs that get grouped together here, and they're very different: a simple cold-loft top-up rolled over the joists; a room-in-roof or warm-roof build-up insulating at the rafter line to keep a converted loft usable; and flat-roof insulation. The right one depends entirely on whether your loft is storage or living space.

We are PAS2030-19 and TrustMark certified and fit everything from straightforward mineral-wool top-ups to full rafter systems with ventilation and condensation control designed in. Many loft measures are fully funded under ECO4 or the Great British Insulation Scheme for eligible households.

Loft & Roof Insulation cost guide

Indicative 2026 pricing for London & the South-East. Every quote is free, fixed and itemised — grants can reduce or remove these figures for eligible households.

Job type	Indicative cost	Notes
Cold-loft top-up (to 270mm)	£400 – £900	Often free under GBIS
Room-in-roof / rafter system	£3,000 – £7,500	Keeps converted lofts usable
Warm flat-roof build-up	£90 – £150 / m²	Done at re-cover stage ideally
Full re-insulation of a 3-bed loft	£700 – £1,500	Including removal of old material

Recent Loft work

Real jobs completed by our own team across London and the South-East.

270mm Mineral Wool & Boarding

Loft insulation in Uxbridge

Suspended Floor Insulation

Mineral Wool in Dulwich

Systems & materials we install

Knauf / Superglass mineral-wool rolls (top-ups)

Kingspan / Celotex PIR boards (rafter and flat roof)

Multifoil systems where depth is limited

Loft-leg boarding kits to keep storage above the insulation

Ventilation and breather membranes to control condensation

How Loft installation works

Free survey

We check existing depth, joist spacing, ventilation and whether the loft is storage or living space to recommend the right build-up.

Quote

A fixed written quote within 24 hours — most cold-loft jobs are quick and many are grant-funded.

Installation

Old material cleared if needed, new insulation laid or rafter system built with correct ventilation; boarding refitted where required.

Sign-off & guarantee

Final inspection, TrustMark paperwork and written guarantee.

Grants for loft & roof insulation

We're TrustMark-registered for ECO4 and the Great British Insulation Scheme. If your household qualifies, this work can be fully or partly funded — we handle the application end-to-end.

Check my eligibility

Loft & Roof Insulation FAQs

How much does loft insulation cost?

A standard cold-loft top-up is £400–£900 and is often fully funded under the Great British Insulation Scheme. A room-in-roof or rafter system runs £3,000–£7,500 because it's a far bigger job that keeps converted space usable.

What depth of loft insulation do I need?

The current recommended depth is 270mm for mineral wool in a cold loft. Many older homes have 100mm or less, so a top-up to 270mm is one of the most cost-effective upgrades available.

Can I still use my loft for storage?

Yes — we fit raised loft-leg boarding so you keep a boarded storage area above the full depth of insulation, rather than squashing it and losing performance.

My loft is converted — what then?

Then you need insulation at the rafter line (a warm-roof or room-in-roof system), not over the floor. It's more involved but stops a converted loft being freezing in winter and stifling in summer.

Will it cause condensation?

Not when ventilation is maintained. We design in the right airflow and, on warm-roof systems, the correct membranes to prevent condensation forming in the structure.

Areas we cover

We install loft & roof insulation across London and the South-East. See all areas we cover →

Wimbledon Kingston upon Thames Hounslow Ruislip

Other insulation services

External Wall Insulation Internal Wall Insulation Floor Insulation

Get a free Loft quote

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