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.
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
Loft & Roof Insulation: key facts
- The cheapest, fastest-payback insulation measure for most homes.
- Around 25% of a home's heat escapes through an uninsulated roof.
- Cold-loft top-up to the 270mm standard: £400–£900, paying back in 2–4 years.
- Room-in-roof and warm-roof rafter systems: £3,000–£7,500.
- Raised loft-leg boarding keeps usable storage above full-depth insulation.
- PAS2030-19 certified, TrustMark registered.
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. Loft measures are usually the lowest-cost, fastest-payback upgrade a home can make.
Loft & Roof Insulation cost guide
Indicative 2026 pricing for London & the South-East, based on hundreds of real quotes and 500+ completed installations — not generic industry averages. Every quote is free, fixed and itemised, with no hidden extras.
| Job type | Indicative cost |
|---|---|
| Cold-loft top-up (to 270mm) | £400 – £900 |
| Room-in-roof / rafter system | £3,000 – £7,500 |
| Warm flat-roof build-up | £90 – £150 / m² |
| Full re-insulation of a 3-bed loft | £700 – £1,500 |
What real jobs actually cost
Anonymised prices from recent jobs our own team won and installed across London and the South-East. Every home differs — your fixed, itemised quote follows a free survey.
| When | Area | Work | Size | Price |
|---|---|---|---|---|
| June 2026 | Crystal Palace (SE19) | Flat roof insulation | 17 m² | £6,735£396/m² |
| June 2026 | Richmond (TW10) | Roof rafter insulation | — | £1,894 |
| June 2026 | East Dulwich (SE22) | Loft insulation top-up | 42 m² | £2,340£56/m² |
| April 2026 | Highgate (N6) | Roof rafter insulation | 105 m² | £11,576£110/m² |
| March 2026 | Finsbury Park (N4) | Loft insulation top-up | 35 m² | £2,600£74/m² |
| February 2026 | Wimbledon (SW19) | Loft insulation top-up | 40 m² | £2,448£61/m² |
| January 2026 | Greenford (UB6) | Loft insulation top-up | 35 m² | £4,580£131/m² |
| November 2025 | Kingston upon Thames (KT2) | Flat roof insulation | 15 m² | £7,242£498/m² |
Prices are real totals paid for the specific scope of each job (access, condition and finishes vary) — use them as honest reference points, not like-for-like quotes. Full cost guide
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
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 low-cost.
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.
Free survey & fixed quote
Book a free, no-obligation survey and we'll send a clear, fixed written quote within 24 hours — PAS2030-19 certified and TrustMark registered, with all work installed by our own trained team.
Get a free quoteLoft & Roof Insulation FAQs
How much does loft insulation cost?
What depth of loft insulation do I need?
Can I still use my loft for storage?
My loft is converted — what then?
Will it cause condensation?
Areas we cover
We install loft & roof insulation across London and the South-East. See all areas we cover →
Other insulation services
Related guides
In-depth, independent guidance to help you decide.
Last reviewed June 2026 by Stay Warm Insulation.
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