Roof Insulation
Rafter-level insulation for loft conversions and habitable roof spaces — warm, comfortable rooms all year round.
- Between-rafter and under-rafter insulation
- Meets Building Regulations for loft conversions
- Fixed pricing with no hidden extras
Habitable Roof Spaces Need Rafter-Level Insulation
When your loft is converted into a living space, standard loft insulation between ceiling joists is no longer an option — there is no ceiling above the room. Instead, insulation must be fitted at rafter level to create a warm, comfortable space directly under the roof. Without proper rafter insulation, loft rooms are unbearably hot in summer, freezing in winter and prone to condensation.
Radiant Roofing installs rafter-level roof insulation across Kent, Sussex and Surrey. We fit rigid PIR boards or breathable insulation between and below the rafters to achieve the U-values required by Building Regulations. Every installation includes a proper vapour barrier and maintains the ventilation gap above the insulation to prevent condensation within the roof structure.
How It Works
Assessment
We inspect the roof structure, measure rafter depth and calculate the insulation build-up needed to achieve the required U-value for your project.
Fixed Quote
You receive a clear quote covering insulation supply, installation, vapour control layer and any preparatory work — no hidden charges.
Expert Installation
We fit insulation between rafters and add an under-rafter layer where needed to achieve the required thermal performance, with a vapour barrier on the warm side.
Guarantee
All roof insulation work is backed by our workmanship guarantee and meets Building Regulations for thermal performance.
Assessment
We inspect the roof structure, measure rafter depth and calculate the insulation build-up needed to achieve the required U-value for your project.
Fixed Quote
You receive a clear quote covering insulation supply, installation, vapour control layer and any preparatory work — no hidden charges.
Expert Installation
We fit insulation between rafters and add an under-rafter layer where needed to achieve the required thermal performance, with a vapour barrier on the warm side.
Guarantee
All roof insulation work is backed by our workmanship guarantee and meets Building Regulations for thermal performance.
What Our Roof Insulation Service Includes
We install rafter-level insulation for loft conversions, habitable attic rooms and any roof space that needs to be thermally efficient. All work meets current Building Regulations.
What Does Roof Insulation Cost?
Typical price range
£500 – £3000
VAT may apply depending on the project
Factors that affect the price:
- 1Roof area to be insulated (square metres)
- 2Rafter depth and required insulation thickness
- 3Insulation type (rigid PIR, breathable, multifoil)
- 4Whether under-rafter battening is needed
Roof insulation for a standard loft conversion costs £500 to £1,500. Larger roof spaces or deep rafter builds requiring thick insulation and under-rafter layers run £1,500 to £3,000. We provide a fixed quote after measuring your roof.
What Our Customers Say
Verified Google ReviewsJane S.
Kent
They were very friendly, professional and polite and left the site immaculate at the end of the day. I would thoroughly recommend them to others. The work was carried out to a very high standard.
Peter B.
East Sussex
Excellent work, highly recommended! Very knowledgeable, by far the best roofing company we have ever used and super nice guys.
Sarah M.
Surrey
Radiant Roofing completed our roof repair quickly and professionally. Great communication throughout and a fantastic result.
Frequently Asked Questions
Roof insulation for a loft conversion typically costs between £500 and £3,000 depending on roof area, rafter depth and the insulation build-up required. A standard rear dormer loft conversion costs £500 to £1,500 for insulation. Mansard or full-width conversions sit higher.
Loft insulation sits between ceiling joists in a cold, unused loft space. Roof insulation sits between the rafters in a habitable room directly under the roof. They serve the same purpose — reducing heat loss — but roof insulation is more complex because it must maintain a ventilation gap and achieve stricter U-values.
In most cases, yes. A 50mm ventilation gap between the insulation and the roof underlay prevents warm, moist air from condensing on the cold underside of the tiles. Some modern breathable underlays reduce this requirement, but we always check and comply with Building Regulations.
We cover Kent, East Sussex, West Sussex and Surrey. Our teams regularly install roof insulation in Tunbridge Wells, Crowborough, Sevenoaks, Tonbridge, Uckfield, Haywards Heath, East Grinstead and surrounding areas.
Yes. All roof insulation is backed by our workmanship guarantee and meets Building Regulations. The insulation materials carry manufacturer warranties and, once installed, require no maintenance.
Contact Us!
Get in touch with us!
Looking for a free quote? Just fill in the form below, and we'll take care of the rest!
Contact Information:
Mobile (24/7): 07753 165 005
Landline (Office Hours): 01892 356 967
Email: contact@radiantroofing.co.uk
Head Office:
Address:
Alpha House
Crowborough Hill
Crowborough
TN6 2EG
Opening Hours:
Monday to Friday: 7:30 am – 6:00 pm
Saturday: 7:30 am – 12:00 pm
Sunday: Closed (mobile still available)
Our Mobile and Email is available 24/7
