Flat Roof Insulation

Stop heat loss, slash energy costs, and keep your building protected from the elements with proper flat roof insulation. Whether you’re tackling a new build or upgrading your current roof, our range of products has what you need for a more comfortable and cost-effective space.

Explore our insulation for flat roofs

Kingspan Kooltherm K110 Plus Soffit Board

Kingspan Kooltherm K110 PLUS Soffit Board is a premium performance insulation with a fibre-free rigid thermoset phenolic core and a building board outer face.

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Kingspan Thermaroof TR24

Kingspan Thermaroof TR24 is a high performance insulation with a fibre-free rigid thermoset polyisocyanurate (PIR) core. It is suitable for flat roofs waterproofed with partially bonded torch applied multi-layer bituminous waterproofing, and has a thermal conductivity of 0.024 - 0.027 W/mK.

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Kingspan Thermaroof TR26

Kingspan Thermaroof TR26 is a high performance insulation with a fibre-free rigid thermoset polyisocyanurate (PIR) core. It is suitable for flat roofs waterproofed with mechanically fixed single-ply waterproofing, and has a thermal conductivity of 0.022 W/mK.

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Kingspan Thermaroof TR27

Kingspan Thermaroof TR27 is a high performance insulation with a fibre-free rigid thermoset polyisocyanurate (PIR) core. With a thermal conductivities as low as 0.024 W/mK, it is used to insulate flat roofs waterproofed with fully adhered single-ply, partially bonded built-up felt, mastic asphalt and cold liquid applied waterproofing.

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Kingspan Thermataper TT46

Kingspan Thermataper TT46 is a high performance insulation with a fibre-free rigid thermoset polyisocyanurate (PIR) core. It is designed to enhance water drainage for flat roofs waterproofed with mechanically fixed single-ply waterproofing.

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Kingspan Thermataper TT47

Kingspan Thermataper TT46 is a high performance insulation with a fibre-free rigid thermoset polyisocyanurate (PIR) core. It is designed to enhance water drainage for flat roofs waterproofed with mechanically fixed single-ply waterproofing.

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MANNOK THERM ROOF / MFR-PLY PIR INSULATION

Flat Roof Insulation: Insulating a flat roof with timber deck insulated above the joists: warm deck insulation

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Ravatherm XPS X 300 SL

Ravatherm XPS X 300 SL is a high-performance, multi-purpose polystyrene for the thermal insulation and frost protection of inverted flat roofs, green and blue roofs.

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Ravatherm XPS X 700 SL

Ravatherm XPS X 700 SL closed-cell polystyrene foam thermal insulation, with its excellent thermal insulation capability, high compressive strength and resistance to moisture, can be safely used in locations where good thermal insulation capability is only one of many complex requirements. It is suitable for load-bearing industrial floors, base slabs or high-load rooftop car parks.

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ROCKWOOL HARDROCK® Multi-Fix (DD) Tapered

Non-combustible tapered insulation for flat roofs. HARDROCK Multi-Fix (DD) Tapered is a BBA-approved insulation board, fabricated to a fall to provide drainage across a roof.

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ROCKWOOL HARDROCK® Multi-Fix Angle Fillet

Stone wool angle fillet for flat roof applications The area between horizontal and vertical interfaces can sometimes be the most challenging part of a flat roof to insulate and seal. HARDROCK® Multi-fix Angle Fillets have been specifically designed to create a smooth transition at 90° abutments, for effective flat roof insulation and waterproofing.

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ROCKWOOL HARDROCK® UB34

Consisting of a dense ROCKWOOL insulation slab bonded to a rigid 6mm exterior-grade fibre cement board, this combination of two non-combustible products provides an impact and weather-resistant insulation solution for flat roof upstands and parapet walls.

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A quick guide to buying flat roof insulation

Worried about dampness in your property? Incredibly chilly in the winter? Sick of spending a fortune on the heating bill? It might be time to look at insulation, and your roof is a good place to start.

When insulating a flat roof, you have two main options:

Warm flat roofs are the most popular method for flat roofs in the UK, and it involves placing the insulation above the roof structure, creating a thermal barrier that prevents heat loss and keeps the building warm. This method is great for reducing energy costs and is commonly used in new builds and re-roofing projects.
Cold flat roofs, on the other hand, have the insulation placed between the rafters or below the roof deck, keeping the roof structure cooler. While it’s often more cost-effective, careful ventilation is needed to prevent condensation.

What are the main benefits?

More comfortable: Roof insulation ensures a more consistent indoor temperature, eliminating the discomfort of extreme heat in summer and cold draughts in winter
Save money: Insulation helps cut down on energy consumption, leading to lower heating bills. Over time, the savings on your energy costs can more than pay for the investment in insulation.
Protection: Quality insulation acts as a barrier, shielding your roof from moisture, condensation, and other damaging effects of the weather.
Soundproofing: Insulation provides an extra layer of soundproofing, helping to reduce noise from rain, wind, and external sources. Enjoy a quieter and more peaceful indoor space, especially in noisy and busy areas.
Energy efficient: increased energy efficiency not only cuts costs but also helps reduce your carbon footprint.

Ready to upgrade your flat roof insulation? Get in touch with our team today for expert advice and top-quality products.

Frequently asked questions

How to insulate a flat roof from the inside?

To insulate a flat roof from the inside, you’ll typically use a cold roof method. This involves placing insulation material, like rigid foam boards or mineral wool, between the joists under the roof deck. Be sure to leave a ventilation gap above the insulation to prevent condensation buildup. Finally, cover the insulation with plasterboard for a clean, finished look. This approach can help improve energy efficiency without disturbing the external roof structure.

How to insulate a flat roof?

Insulating a flat roof can be done using two main methods: warm roof or cold roof insulation. A warm roof involves placing the insulation above the roof deck, creating a thermal barrier that improves energy efficiency and protects against moisture. In a cold roof, insulation is installed between the rafters below the roof deck. Both methods improve comfort, lower energy costs, and extend the roof’s lifespan.

Flat Roof Insulation

Explore our insulation for flat roofs

Kingspan Kooltherm K110 Plus Soffit Board

Kingspan Thermaroof TR24

Kingspan Thermaroof TR26

Kingspan Thermaroof TR27

Kingspan Thermataper TT46

Kingspan Thermataper TT47

MANNOK THERM ROOF / MFR-PLY PIR INSULATION

Ravatherm XPS X 300 SL

Ravatherm XPS X 700 SL

ROCKWOOL HARDROCK® Multi-Fix (DD) Tapered

ROCKWOOL HARDROCK® Multi-Fix Angle Fillet

ROCKWOOL HARDROCK® UB34

A quick guide to buying flat roof insulation

What are the main benefits?

Where service means

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