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100mm Celotex GA4100 PIR Insulation Board 2400mm x 1200mm (8′ x 4′) 2.88m2
100mm Celotex GA4100 is a polyisocyanurate (PIR) insulation core with composite aluminium foil facings on both sides. Celotex is a multi-purpose insulation board suitable for use in pitched roofs, ceilings, floors and walls.
£36.82£44.18 Ex VATInc VAT£12.78£15.34 Per M2 Add to cart -
100mm Ecotherm Eco-Versal Rigid PIR Insulation Board 2400mm x 1200mm (8′ x 4′) 2.88m2
100mm Ecotherm Eco-Versal is a polyisocyanurate (PIR) insulation core with composite aluminium foil facings on both sides. Ecotherm Eco-Versal is a multi-purpose insulation board suitable for use in pitched roofs, ceilings, floors and walls.
£40.34£48.41 Ex VATInc VAT£14.01£16.81 Per M2 Add to cart -
100mm Kingspan GreenGuard GG300 R Rigid Extruded Polystyrene Insulation Board 1250mm x 600mm Pack of 4 (3.00m2)
100mm Kingspan GreenGuard GG300 is a high performance rigid extruded polystyrene insulation. It is used to insulate inverted roofs, basements, car park decks, and heavy-duty commercial, industrial and cold store flooring offering a thermal conductivities as low as 0.033 W/mK.
£64.92£77.90 Ex VATInc VAT£21.64£25.97 Per M2 Add to cart -
100mm Kingspan Kooltherm K107 Pitched Roof Board 2400mm x 1200mm Pack of 3 (8.64m2)
100mm Kingspan Kooltherm K107 Pitched Roof Board is a premium performance insulation with a fibre-free rigid thermoset phenolic core. It is used to insulate pitched roofs and attic spaces, and has a thermal conductivity of just 0.019 W/m.K across all thicknesses.
£326.98£392.38 Ex VATInc VAT£37.84£45.41 Per M2 Add to cart -
100mm Kingspan Thermaroof TR24 Flat Roof PIR Insulation Board 1200mm x 600mm Pack of 5 (3.60m2)
100mm Kingspan Thermaroof TR24 is a high performance insulation with a fibre-free rigid thermoset polyisocyanurate (PIR) core. Kingspan Thermaroof is suitable for flat roofs waterproofed with partially bonded torch applied multi-layer bituminous waterproofing.
£130.26£156.31 Ex VATInc VAT£36.18£43.42 Per M2 Add to cart -
100mm Kingspan Thermaroof TR26 PIR Insulation Board 2400mm x 1200mm (8′ x 4′) Pack of 3 (8.64m2)
100mm Kingspan TR26 Thermaroof is high-performance insulation that has a fiber-free rigid thermoset polyisocyanurate (PIR) core. Suitable for flat roof application waterproofed with mechanically fixed single-ply waterproofing.
£268.97£322.76 Ex VATInc VAT£31.13£37.36 Per M2 Add to cart -
100mm Kingspan Thermaroof TR27 PIR Insulation Board 1200mm x 1200mm Pack of 4 (5.76m2)
100mm Kingspan Thermaroof TR27 is a high performance insulation with a fibre-free rigid thermoset polyisocyanurate (PIR) core. 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.
£187.58£225.10 Ex VATInc VAT£32.57£39.08 Per M2 Add to cart -
100mm Recticel Eurothane GP PIR Insulation Board 2400mm x 1200mm (8′ x 4′) 2.88m2
100mm Recticel Eurothane GP is a polyisocyanurate (PIR) insulation core with composite aluminium foil facings on both sides. Recticel is a multi-purpose insulation board suitable for use in pitched roofs, ceilings, floors and walls.
£37.18£44.62 Ex VATInc VAT£12.91£15.49 Per M2 Add to cart -
110mm Kingspan Thermaroof TR26 PIR Insulation Board 2400mm x 1200mm (8′ x 4′) Pack of 3 (8.64m2)
110mm Kingspan TR26 Thermaroof is high-performance insulation that has a fiber-free rigid thermoset polyisocyanurate (PIR) core. Suitable for flat roof application waterproofed with mechanically fixed single-ply waterproofing.
£305.50£366.60 Ex VATInc VAT£35.36£42.43 Per M2 Add to cart -
110mm Recticel Eurothane GP PIR Insulation Board 2400mm x 1200mm (8′ x 4′) 2.88m2
110mm Recticel Eurothane GP is a polyisocyanurate (PIR) insulation core with composite aluminium foil facings on both sides. Recticel is a multi-purpose insulation board suitable for use in pitched roofs, ceilings, floors and walls.
£45.43£54.52 Ex VATInc VAT£15.77£18.92 Per M2 Add to cart -
110mm Unilin Thin-R PIR Insulation Board 2400mm x 1200mm (8′ x 4′) Pallet of 21 (60.48m2)
110mm Unilin Thin-R PIR insulation is a foil faced, high-performance insulation solution that offers exceptional thermal efficiency and durability. This polyisocyanurate insulation board, formerly known as Xtratherm, is ideal for a range of applications, such as floors, pitched roofs, and walls.
POA Get a quote -
120mm Celotex XR4120 PIR Insulation Board 2400mm x 1200mm (8′ x 4′) 2.88m2
120mm Celotex XR4120 is a polyisocyanurate (PIR) insulation core with composite aluminium foil facings on both sides. Celotex is a multi-purpose insulation board suitable for use in pitched roofs, ceilings, floors and walls.
£46.38£55.66 Ex VATInc VAT£16.10£19.32 Per M2 Add to cart -
120mm Ecotherm Eco-Versal Rigid PIR Insulation Board 2400mm x 1200mm (8′ x 4′) 2.88m2
120mm Ecotherm Eco-Versal is a polyisocyanurate (PIR) insulation core with composite aluminium foil facings on both sides. Ecotherm Eco-Versal is a multi-purpose insulation board suitable for use in pitched roofs, ceilings, floors and walls.
£50.68£60.82 Ex VATInc VAT£17.60£21.12 Per M2 Add to cart -
120mm Kingspan GreenGuard GG300 R Rigid Extruded Polystyrene Insulation Board 1250mm x 600mm Pack of 3 (2.25m2)
120mm Kingspan GreenGuard GG300 is a high performance rigid extruded polystyrene insulation. It is used to insulate inverted roofs, basements, car park decks, and heavy-duty commercial, industrial and cold store flooring offering a thermal conductivities as low as 0.033 W/m·K
£59.33£71.20 Ex VATInc VAT£26.37£31.64 Per M2 Add to cart -
120mm Kingspan Kooltherm K107 Pitched Roof Board 2400mm x 1200mm Pack of 2 (5.76m2)
120mm Kingspan Kooltherm K107 Pitched Roof Board is a premium performance insulation with a fibre-free rigid thermoset phenolic core. It is used to insulate pitched roofs and attic spaces, and has a thermal conductivity of just 0.019 W/m.K across all thicknesses.
£258.34£310.01 Ex VATInc VAT£44.85£53.82 Per M2 Add to cart -
120mm Kingspan Thermaroof TR24 Flat Roof PIR Insulation Board 1200mm x 600mm Pack of 4 (2.88m2)
120mm Kingspan Thermaroof TR24 is a high performance insulation with a fibre-free rigid thermoset polyisocyanurate (PIR) core. Kingspan Thermaroof is suitable for flat roofs waterproofed with partially bonded torch applied multi-layer bituminous waterproofing.
£117.43£140.92 Ex VATInc VAT£40.77£48.92 Per M2 Add to cart -
120mm Kingspan Thermaroof TR26 PIR Insulation Board 2400mm x 1200mm (8′ x 4′) Pack of 2 (5.76m2)
120mm Kingspan TR26 Thermaroof is high-performance insulation that has a fiber-free rigid thermoset polyisocyanurate (PIR) core. Suitable for flat roof application waterproofed with mechanically fixed single-ply waterproofing.
£205.18£246.22 Ex VATInc VAT£35.62£42.74 Per M2 Add to cart -
120mm Kingspan Thermaroof TR27 PIR Insulation Board 1200mm x 1200mm Pack of 4 (5.76m2)
120mm Kingspan Thermaroof TR27 is a high performance insulation with a fibre-free rigid thermoset polyisocyanurate (PIR) core. 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.
£210.43£252.52 Ex VATInc VAT£36.53£43.84 Per M2 Add to cart -
120mm Recticel Eurothane GP PIR Insulation Board 2400mm x 1200mm (8′ x 4′) 2.88m2
120mm Recticel Eurothane GP is a polyisocyanurate (PIR) insulation core with composite aluminium foil facings on both sides. Recticel is a multi-purpose insulation board suitable for use in pitched roofs, ceilings, floors and walls.
£45.86£55.03 Ex VATInc VAT£15.92£19.10 Per M2 Add to cart -
130mm Celotex XR4130 PIR Insulation Board 2400mm x 1200mm (8′ x 4′) 2.88m2
130mm Celotex XR4130 is a polyisocyanurate (PIR) insulation core with composite aluminium foil facings on both sides. Celotex is a multi-purpose insulation board suitable for use in pitched roofs, ceilings, floors and walls.
£60.85£73.02 Ex VATInc VAT£21.13£25.36 Per M2 Add to cart -
130mm Kingspan Thermaroof TR24 Flat Roof PIR Insulation Board 1200mm x 600mm Pack of 3 (2.16m2)
130mm Kingspan Thermaroof TR24 is a high performance insulation with a fibre-free rigid thermoset polyisocyanurate (PIR) core. Kingspan Thermaroof is suitable for flat roofs waterproofed with partially bonded torch applied multi-layer bituminous waterproofing.
£94.36£113.23 Ex VATInc VAT£43.69£52.43 Per M2 Add to cart -
130mm Kingspan Thermaroof TR27 PIR Insulation Board 1200mm x 1200mm Pack of 3 (4.32m2)
130mm Kingspan Thermaroof TR27 is a high performance insulation with a fibre-free rigid thermoset polyisocyanurate (PIR) core. 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.
£170.22£204.26 Ex VATInc VAT£39.40£47.28 Per M2 Add to cart -
140mm Celotex XR4140 PIR Insulation Board 2400mm x 1200mm (8′ x 4′) 2.88m2
140mm Celotex XR4140 is a polyisocyanurate (PIR) insulation core with composite aluminium foil facings on both sides. Celotex is a multi-purpose insulation board suitable for use in pitched roofs, ceilings, floors and walls.
£57.43£68.92 Ex VATInc VAT£19.94£23.93 Per M2 Add to cart -
140mm Kingspan Thermaroof TR27 PIR Insulation Board 1200mm x 1200mm Pack of 2 (2.88m2)
140mm Kingspan Thermaroof TR27 is a high performance insulation with a fibre-free rigid thermoset polyisocyanurate (PIR) core. 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.
£125.82£150.98 Ex VATInc VAT£43.69£52.43 Per M2 Add to cart -
140mm Recticel Eurothane GP PIR Insulation Board 2400mm x 1200mm (8′ x 4′) 2.88m2
140mm Recticel Eurothane GP is a polyisocyanurate (PIR) insulation core with composite aluminium foil facings on both sides. Recticel is a multi-purpose insulation board suitable for use in pitched roofs, ceilings, floors and walls.
£53.14£63.77 Ex VATInc VAT£18.45£22.14 Per M2 Add to cart -
150mm Celotex XR4150 PIR Insulation Board 2400mm x 1200mm (8′ x 4′) 2.88m2
150mm Celotex XR4150 is a polyisocyanurate (PIR) insulation core with composite aluminium foil facings on both sides. Celotex is a multi-purpose insulation board suitable for use in pitched roofs, ceilings, floors and walls.
£55.56£66.67 Ex VATInc VAT£19.29£23.15 Per M2 Add to cart -
150mm Ecotherm Eco-Versal Rigid PIR Insulation Board 2400mm x 1200mm (8′ x 4′) 2.88m2
The 150mm Ecotherm Eco-Versal is a polyisocyanurate (PIR) insulation core with composite aluminium foil facings on both sides. Ecotherm Eco-Versal is a multi-purpose insulation board suitable for use in pitched roofs, ceilings, floors and walls.
£60.22£72.26 Ex VATInc VAT£20.91£25.09 Per M2 Add to cart -
150mm Kingspan GreenGuard GG300 R Rigid Extruded Polystyrene Insulation Board 1250mm x 600mm Pack of 2 (1.50m2)
150mm Kingspan GreenGuard GG300 is a high performance rigid extruded polystyrene insulation. It is used to insulate inverted roofs, basements, car park decks, and heavy-duty commercial, industrial and cold store flooring offering a thermal conductivities as low as 0.034 W/m·K.
Non-refundable.
£49.03£58.84 Ex VATInc VAT£32.69£39.23 Per M2 Add to cart -
150mm Kingspan Thermaroof TR26 PIR Insulation Board 2400mm x 1200mm (8′ x 4′) Pack of 2 (5.76m2)
150mm Kingspan TR26 Thermaroof is high-performance insulation that has a fiber-free rigid thermoset polyisocyanurate (PIR) core. Suitable for flat roof application waterproofed with mechanically fixed single-ply waterproofing.
£255.76£306.91 Ex VATInc VAT£44.40£53.28 Per M2 Add to cart -
150mm Kingspan Thermaroof TR27 PIR Insulation Board 1200mm x 1200mm Pack of 2 (2.88m2)
150mm Kingspan Thermaroof TR27 is a high performance insulation with a fibre-free rigid thermoset polyisocyanurate (PIR) core. 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.
£132.69£159.23 Ex VATInc VAT£46.07£55.28 Per M2 Add to cart -
150mm Recticel Eurothane GP PIR Insulation Board 2400mm x 1200mm (8′ x 4′) 2.88m2
150mm Recticel Eurothane GP is a polyisocyanurate (PIR) insulation core with composite aluminium foil facings on both sides. Recticel is a multi-purpose insulation board suitable for use in pitched roofs, ceilings, floors and walls.
£53.56£64.27 Ex VATInc VAT£18.60£22.32 Per M2 Add to cart -
25mm Celotex PIR Insulated Plasterboard 1200mm x 2400mm + 12.5mm P/B 2.88m2
25mm + 12.5mm Celotex PL4025 PIR Insulated Plasterboard is it is suitable for use in roof and internal wall lining applications. Celotex Insulated Plasterboard is a high performance, easy to install PIR insulation board with a paper facing, laminated to a piece of 12.5mm tapered edge plasterboard.
£41.49£49.79 Ex VATInc VAT£14.41£17.29 Per M2 Add to cart -
25mm Celotex TB4025 PIR Insulation Board 2400mm x 1200mm (8′ x 4′) 2.88m2
25mm Celotex TB4025 is a polyisocyanurate (PIR) insulation core with composite aluminium foil facings on both sides. Celotex is a multi-purpose insulation board suitable for use in pitched roofs, ceilings, floors and walls.
£14.03£16.84 Ex VATInc VAT£4.87£5.84 Per M2 Add to cart -
25mm Kingspan Kooltherm K107 Pitched Roof Board 2400mm x 1200mm Pack of 12 (34.56m2)
25mm Kingspan Kooltherm K107 Pitched Roof Board is a premium performance insulation with a fibre-free rigid thermoset phenolic core. It is used to insulate pitched roofs and attic spaces, and has a thermal conductivity of just 0.019 W/m.K across all thicknesses.
£444.97£533.96 Ex VATInc VAT£12.88£15.46 Per M2 Add to cart -
25mm Kingspan Thermaroof TR26 PIR Insulation Board 2400mm x 1200mm (8′ x 4′) Pack of 12 (34.56m2)
25mm Kingspan TR26 Thermaroof is high-performance insulation that has a fiber-free rigid thermoset polyisocyanurate (PIR) core. Suitable for flat roof application waterproofed with mechanically fixed single-ply waterproofing.
£391.06£469.27 Ex VATInc VAT£11.32£13.58 Per M2 Add to cart -
25mm Kingspan Thermaroof TR27 PIR Insulation Board 1200mm x 600mm Pack of 12 (8.64m2)
25mm Kingspan Thermaroof TR27 is a high performance insulation with a fibre-free rigid thermoset polyisocyanurate (PIR) core. 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.
£104.06£124.87 Ex VATInc VAT£12.04£14.45 Per M2 Add to cart
Our specialist stores
Our specialist stores
Roof Insulation Board
Roof insulation boards are often fixed across flat roof systems, above rafters, or below ceilings. They help meet UK Building Regulations and enhance thermal performance when installed correctly.
What is the roof insulation board?
Roof insulation boards are rigid thermal panels that boost a roof’s energy performance and structural stability. They are commonly made from materials such as PIR (polyisocyanurate), XPS, or EPS foam and provide reliable thermal resistance. They are also known for their compressive strength and long-term weather resistance.
They can be installed beneath tiles as sarking boards, above roof decks as roofing boards, or internally as ceiling insulation boards.
What is roof insulation board used for?
Roof insulation boards can be installed across various roofing systems, depending on the project type and energy goals. They are widely used for:
- Pitched roofs: Installed as sarking board above rafters to minimise heat escape and condensation.
- Flat roofs: Used as flat roof insulation boards beneath waterproof membranes to enhance thermal performance.
- Loft, attic, and garage ceilings: These are installed between or under joists as ceiling insulation boards to improve indoor warmth.
- Over-rafter systems: Used externally as continuous roof insulation panels to eliminate thermal bridging.
- Refurbishment and conversions: Ideal for upgrading older roofs to meet current Part L energy efficiency standards.
Types of roof insulation board
Insulation Wholesale offers insulation boards for roofs that are suitable for every project. Choose from:
- PIR Roof Insulation Boards: These are high-performance boards with superior thermal conductivity and compressive strength. All types can be used with vapour control layers and compatible waterproofing membranes where required.
- XPS Roof Insulation Boards: Moisture-resistant and durable. Ideal for inverted and flat roof installations.
- EPS Roof Insulation Boards: Light and cost-effective, with good thermal efficiency.
Benefits of roof insulation board
A well-insulated roof helps increase long-term comfort and energy savings for buildings. This is why roof insulation panels are a must-have for modern builds and refurbishments:
- Reduce heat loss: They keep warmth inside during winter and deflect heat in summer.
- Enhance building efficiency: They improve U-values to help meet Part L Building Regulations.
- Perfect for flat and pitched roofs: They work equally well under tiles, membranes, and metal sheeting.
- Moisture and mould protection: XPS and PIR variants resist water absorption and condensation. They are particularly effective when combined with vapour control layers.
- Improve structural performance: They add rigidity to roof decks and help distribute loads evenly when used within approved assemblies.
Why choose our roof insulation board?
Here’s what makes Insulation Wholesale the trusted choice for roof insulation boards in the UK:
- A comprehensive range of roof insulation sheets and flat roof insulation boards.
- Products from leading brands known for reliability and thermal performance.
- Solutions for new builds, refurbishments, and under-deck insulation systems.
- Expert advice to help you select the right roofing board for your project.
- Trade pricing, bulk savings, and fast nationwide delivery to the site or home.
Keep your building warm and compliant with our premium flat roof insulation panels. Shop now for fast UK delivery and proven thermal performance.
At Insulation Wholesale, you can purchase Roof Insulation Board at low wholesale prices with fast delivery for most of items within 2-5 days. Competitive rates guaranteed.
FAQ
What thickness insulation board for roof?
Roof insulation thickness depends on the type of roof and the target U-value. Typically, both pitched and flat roofs need 100–150 mm boards to achieve modern thermal performance standards.
How to install foam board insulation on roof?
For over-rafter installations:
- Step: Fix the roof foam board insulation directly to the rafters using mechanical fasteners.
- Step: Seal joints with foil tape.
- Step: Install counter battens.
- Step: Fit the roof covering.
Always check manufacturer guidance for fixing and vapour control requirements.
How to install insulation board on flat roof?
- Step: Lay flat roof insulation boards on the roof deck, ensuring a clean and dry surface.
- Step: Tightly butt, stagger, and secure the boards with appropriate fixings or adhesive.
- Step: Apply a waterproof membrane over the insulation.
For inverted roofs, install above the membrane with protection layers as per design.
What is the minimum insulation for a flat roof?
To meet UK Building Regulations, a flat roof typically requires a U-value of 0.18 W/m²K. Depending on the insulant’s conductivity, this often equates to around 120 mm PIR board.
