Group A · Loft and roof insulation
Pitched roof insulation from inside
Insulation between and under the rafters to turn a cold loft into a warm one.
Typical price
Pitched roof insulation from inside
£45–£80 per m²
Pitched roof between/under-rafter PIR (from inside)
Ask for a quoteBefore grants · updated 11 October 2026 · a survey confirms the final figure.
- Best for
- Converting a cold loft to a warm loft
- Guarantee or standard
- Condensation risk check
- Time on site
- Usually a few days for a typical roof, confirmed at survey.
- Typical price
- £45–£80 per m²
What it is
What is pitched roof insulation from inside?
Insulation between and under the rafters to turn a cold loft into a warm one.
Best for: Converting a cold loft to a warm loft.
Build-up
Pitched roof from inside
Outside
Warm loft
- 1Tiles or slates
- 2Breathable membrane or ventilated gap
- 3Insulation between the raftersPIR, phenolic or wood-fibre
- 4Insulation under the rafters
- 5Plasterboard
Who it suits
Which homes is pitched roof insulation from inside suitable for?
Is my home suitable?
Pick your property type for a straight answer on pitched roof insulation from inside.
Guidance only — every home is different, and a survey confirms what suits yours.
Houses
- Detached house
- Semi-detached house
- End-of-terrace
- Mid-terrace
- Townhouse
- Mews house and cottage
- Detached bungalow
- Semi and terraced bungalow
- Chalet and dormer bungalow
- Period home
- 1930s home
- Post-war and ex-council house
- Non-traditional / system-built
- Listed building or conservation area
- Farmhouse, barn conversion or rural home
- New build or self-build
Flats and blocks of flats
Commercial and public buildings
Usually suitable Depends — a survey confirms
Not usually suitable for 1 property type
- Park and mobile home — Park and mobile homes need specialist systems, which we arrange through a partner rather than standard measures.
Materials and brands
What we use
Between- and under-rafter PIR or phenolic (Kingspan, Celotex, Recticel, Xtratherm) or wood-fibre, with ventilation or breathable membrane.
Insulation brands we work with
- Knauf Insulation (Earthwool, Supafil blown)
- Rockwool
- Superglass
- Isover
- Kingspan
- Celotex
- Recticel
- Xtratherm
- Steico wood-fibre
- YBS and Actis multifoil
The exact system and brand for your home are confirmed in your written quote.
Heat, bills and EPC
What it does for your heat loss, bills and EPC
Heat rises, so a poorly insulated roof is often the largest single route out for heat. Insulating it lowers the roof's U-value — how easily heat passes through — so the heating runs less and the EPC rating usually improves. The gain is largest where there's little insulation now; topping up a loft that's already reasonably insulated gains less.
See the EPC points and savings for your home in the EPC plannerU-value before and after, typical heat and bill saving, and EPC points — worked out for your property.Price
How much does pitched roof insulation from inside cost?
| Service | Typical range, installed |
|---|---|
| Pitched roof between/under-rafter PIR (from inside) | £45–£80 per m² |
Indicative ranges for London and the South East, supplied and installed, including VAT. Updated 11 October 2026. A survey confirms your final price.
0% VAT on energy-saving materials
Insulation, solar panels, batteries and heat pumps installed in homes in Great Britain are zero-rated for VAT until 31 March 2027. Windows and doors are not included.What to expect
Time on site, disruption and approvals
Time on site
Usually a few days for a typical roof, confirmed at survey.
Disruption
Low — the work happens in the loft or roof space. We need clear access to the hatch, with stored items moved to one side.
Planning and building control
We check condensation risk before fitting. If the roof space becomes a habitable room, Building Regulations apply in full.
Guarantee and standard
Condensation risk check. The guarantee and certification for your job are confirmed in writing in your quote.
60-second grant check
Could a grant help pay for it?
Grant eligibility checker
About 60 seconds · plain results: likely, possibly or not eligible
Before we start
What type of property is it?
Questions
Pitched roof insulation from inside: your questions answered
How much does pitched roof insulation from inside cost?
Typically £45–£80 per m² for pitched roof between/under-rafter pir (from inside), installed in London and the South East, including VAT and before any grant. Prices updated 11 October 2026. A survey confirms your final figure.
What's the difference between a cold loft and a warm loft?
In a cold loft the insulation sits on the ceiling and the roof space stays cold. In a warm loft the insulation follows the roof slope, so the roof space is inside the warm envelope — useful for storage, plant or a future conversion.
Why do you need a condensation risk check?
Moving insulation to the rafters changes where moisture can condense. We check the build-up, ventilation and membrane first so the timbers stay dry.
Which materials do you use for pitched roofs?
PIR or phenolic boards (Kingspan, Celotex, Recticel, Xtratherm) between and under the rafters, or wood-fibre for a breathable roof, with ventilation or a breathable membrane as the roof needs.
Group A
More in loft and roof insulation
Loft insulation
Mineral wool laid between and across the joists to 270–300 mm so heat stays in the rooms below.
Loft insulation top-up
An extra cross-layer over existing insulation to reach the recommended 270 mm or more.
Blown loft insulation
Loose-fill insulation blown into awkward, shallow or low-headroom lofts that rolls can't reach.
Loft clearance and replacement
Old, damp or damaged insulation removed, the loft cleaned, then new mineral wool fitted.
Raised loft boarding and storage
Loft legs or raised boarding over full-depth insulation, so storage doesn't crush it.
Insulated loft hatch and ladders
An insulated, draught-sealed hatch and loft ladder — a small add-on that stops a big leak.
Begin your project
Ready to talk about pitched roof insulation from inside?
Tell us about your home and we'll arrange a survey, then a fixed written quote — no obligation.