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50mm Celotex CW4050 Cavity Wall Insulation Board 1200mm x 450mm 5.94m2 Pack of 11 (5.94m2)
50mm Celotex CW4050 Cavity Wall Insulation Board is an easy to install polyisocyanurate (PIR) insulation board with excellent thermal performance, featuring a low emissivity foil facing.
£68.51£82.21 Ex VATInc VAT£11.53£13.84 Per M2 Add to cart -
50mm Celotex GA4050 PIR Insulation Board 2400mm x 1200mm (8′ x 4′) 2.88m2
50mm Celotex GA4050 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.
£22.20£26.64 Ex VATInc VAT£7.71£9.25 Per M2 Add to cart -
50mm Ecotherm Eco-Versal PIR Insulation Board 2400mm x 1200mm (8′ x 4′) 2.88m2
50mm 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.
£22.87£27.44 Ex VATInc VAT£7.94£9.53 Per M2 Add to cart -
50mm Recticel Eurothane GP PIR Insulation Board 2400mm x 1200mm (8′ x 4′) 2.88m2
50mm 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.
£22.30£26.76 Ex VATInc VAT£7.74£9.29 Per M2 Add to cart -
50mm Rockwool RWA45 Acoustic Insulation Slab 1200 x 600mm 6.48m2 Pack
50mm Rockwool RWA45 has been developed for thermal, acoustic and fire performance in a range of construction types. It is suitable for applications on partition walls, ceilings, floors and roofs.
£29.96£35.95 Ex VATInc VAT£4.62£5.54 Per m2 Add to cart -
50mm Ecotherm Eco-Bond PIR Insulation Board 1200mm x 1200mm (4′ x 4′) Pack of 6 (8.64m2)
50mm Eco-Bond PIR insulation boards provide a lightweight, easy-to-install solution for new roofs or upgrading existing ones. Ideal for use with fully adhered single-ply waterproofing on concrete, metal, and timber decks.
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50mm Ecotherm Eco-Cavity Partial Fill Insulation Board 1200mm x 450mm Pack of 10 (5.40m2)
50mm Ecotherm Eco-Cavity wall insulation boards are ideal for masonry walls. They achieve high levels of thermal performance for thinner constructions whilst maintaining a clear residual air gap; effective protection against driving rain, particularly in coastal and exposed locations.
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50mm Ecotherm Eco-Torch PIR Insulation Board 1200mm x 600mm (4′ x 2′) Pack of 6 (4.32m2)
50mm Eco-Torch PIR Insulation Board is a flexible insulation option, perfect for torch-on, roll-and-pour felt systems, mastic asphalt, and single-ply systems.
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50mm IKO Enertherm ALU PIR Insulation Board 2400mm x 1200mm (8′ x 4′) 2.88m2
50mm IKO Enertherm ALU PIR (polyisocyanurate) insulation is a top-quality insulation board featuring a rigid PIR foam core and reflective aluminium foil facings. It delivers outstanding thermal performance and moisture resistance, making it suitable for various installations and an ideal choice for different energy-efficient projects.
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50mm Kingspan OPTIM-R Flooring Insulation Board
50mm Kingspan OPTIM-R Flooring Insulation Panels achieve a declared thermal conductivity of 0.007 W/m∙K.
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50mm Kingspan OPTIM-R Roofing Insulation Board
50mm Kingspan OPTIM-R Roofing Insulation Panels achieve a declared thermal conductivity of 0.007 W/m∙K.
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50mm Kingspan Therma TP10 / TF70 / TW55 PIR Insulation Board 2400mm x 1200mm (8′ x 4′) Pack of 6 (17.28m2)
All three models 50mm Kingspan Therma PIR Insulation Board:
- 50mm Thermapitch TP10
- 50mm Thermafloor TF70
- 50mm Thermawall TW55
share the same high-performance PIR core and low-emissivity foil facings, offering excellent thermal efficiency and easy installation. Although labeled differently, these boards share identical technical specifications.
£198.59£238.31 Ex VATInc VAT£11.49£13.79 Per M2 Add to cart -
50mm Knauf Rocksilk RS45 Building Insulation Slab 1200mm x 600mm 7.2m2 Pack
50mm Knauf Insulation Rocksilk RS45 is a Rock Mineral Wool slab, designed for use in multiple thermal and acoustic applications. It is non-combustible with the best possible Euroclass A1 reaction to fire classification.
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50mm Rockwool Ablative Coated Batt 1200mm x 600mm x 0.72m2
50mm Rockwool Ablative Coated Batt is a mineral wool insulation product, pre-coated on both sides with a high performance ablative coating. Rockwool Ablative Coated Batt application includes multiple substrates including solid walls and floors and flexible walls.
£23.41£28.09 Ex VATInc VAT Add to cart -
50mm Rockwool Flexi Slab Acoustic Insulation 1200mm x 600mm 8.64m2 Pack
50mm Rockwool Flexi has been designed as a multi-use, dual-purpose acoustic and thermal mineral wool insulation with a unique flexible edge along one side. It is suitable for use all over the home, in pitched roof rafters, framed external walls, internal partitions, intermediate floors, separating walls and floors, and timber suspended ground floors.
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50mm Rockwool Rainscreen Duo Slab 1200mm x 600mm 69.12m2 Pallet
50mm Rainscreen Duo Slab is dual-density insulation specifically developed for use within ventilated cladding systems, as well as sealed systems such as curtain walling. Once installed, the robust outer surface of the slabs, in combination with a factory applied water-repelling agent, acts to resist rain ingress during construction.
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50mm Rockwool RW3 Acoustic Insulation Slab 1200mm x 600mm 69.12m2 Pallet
50mm Rockwool RW3 Slabs can be applied to an array of general building applications for acoustic, thermal and fire protection of partition walls, ceilings, floors and roofs.
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50mm Rockwool RW4 Acoustic Insulation Slab 1200mm x 600mm 69.12 m2 Pallet
50mm Rockwool RW4 Slabs can be applied to an array of general building applications for acoustic, thermal and fire protection of partition walls, ceilings, floors and roofs.
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50mm Rockwool RW5 Acoustic Insulation Slab 1200mm x 600mm 69.12m2 Pallet
50mm Rockwool RW5 Slabs can be applied to an array of general building applications for acoustic, thermal and fire protection of partition walls, ceilings, floors and roofs.
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50mm Unilin Thin-R PIR Insulation Board 2400mm x 1200mm (8′ x 4′) Pallet of 48 (138.24m2)
50mm 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.
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50mm Insulation Thermal
50mm insulation is a relatively thin thermal layer used when space is limited, but heat loss still needs to be reduced. In most cases, it does not replace deep insulation systems.
Instead, it improves performance where thicker products simply will not fit. It boosts comfort and efficiency without major structural changes.
What is 50mm thick insulation?
50mm thick insulation measures 50 millimetres from face to face when installed.
With 50mm insulation, heat transfers more slowly than it would through bare masonry, timber, or metal. The material achieves this by:
- Trapping still air (or gas) inside its structure
- Reducing direct heat-conduction paths through the building fabric
50mm thickness insulation is on the thinner side and relies heavily on the quality of the material, not just depth. High-performance boards can outperform softer products at the same thickness.
This is why thin 50mm insulation is often paired with other layers.
What is 50mm thin insulation used for?
50mm insulation is used where build-ups must stay slim, such as:
- Internal wall linings where room size matters
- Service zones in timber frames
- Upgrades to older buildings with shallow cavities
- Floors or ceilings where levels cannot be raised much
It is also used to reduce thermal bridging when correctly detailed and continuous. Even a thin layer can prevent heat from escaping quickly from cold surfaces.
50mm insulation is not chosen for maximum performance. It is chosen to control heat loss without redesigning the structure.
Types of 50mm insulation thickness
The most widely used 50mm insulation materials are:
EPS Insulation (50mm Expanded Polystyrene)
At 50mm thickness, EPS:
- Offers basic thermal resistance.
- Handles moisture well. It is, however, not vapour-tight, and should be used with a vapour control layer.
- Has good compressive strength for its weight.
EPS relies mainly on trapped air, so its thermal performance per millimetre is lower than that of rigid foams. It is commonly chosen when cost and moisture tolerance are desired over outright efficiency.
Phenolic Insulation
At 50mm insulation depth, phenolic:
- Delivers very high thermal resistance per millimetre
- Performs well where space is limited
- Is commonly used in wall linings and soffits
It insulates effectively per millimetre, with 50mm thickness able to match or exceed the performance of thicker PIR or mineral wool.
PIR (Polyisocyanurate)
At insulation 50mm thick, PIR:
- Provides strong thermal resistance
- Is easy to cut and fit accurately
- Works well in walls, floors, and roofs
PIR is often the default choice because it is robust and easy to handle.
Rock Mineral Wool Insulation
At 50mm thick insulation, mineral wool:
- Offers sound absorption as well as thermal resistance
- Is vapour-permeable
- Offers excellent fire resistance.
Its thermal performance per millimetre is lower than that of rigid boards. But its acoustic and fire performance often makes it the right choice for spaces that require high sound and fire protection.
Additional insulation materials available at 50mm include glass mineral wool, XPS, vacuum insulation panel, and stone wool.
FAQ
Where to buy 50mm thick insulation?
You can buy 50mm insulation online from Insulation Wholesale. We stock a wide range of 50mm thick insulation from leading manufacturers, including rigid boards and mineral wool. We offer:
- Clear technical advice
- Consistent UK stock
- Fast delivery options
- Trade pricing
If unsure which 50mm insulation is right for your project, our team will walk you through the best options.
How to cut 50mm insulation?
Rigid boards (PIR, phenolic, EPS): Use a fine-tooth saw or insulation knife. Score, snap, then trim cleanly.
Mineral wool: Use a long serrated blade. Compress slightly, cut once, and avoid tearing.
How to install 50mm insulation?
50mm insulation often sits behind plasterboard, between studs, or over solid surfaces. The fixing method depends on the substrate used.
Installation must keep the insulation continuous:
- Fit boards tightly together.
- Avoid crushing soft materials. Insert them gently, ensuring they fill the whole space.
- Seal gaps where air could move.
- Keep insulation dry during install.
How good is 50mm insulation?
50mm insulation is moderately effective, not powerful. It improves comfort and reduces heat loss, but it does not transform a building on its own.
Here’s what 50mm insulation does well:
- Cuts surface heat loss – Cold walls and ceilings lose heat fast. Adding insulation 50mm thick reduces that loss and raises surface temperatures. This reduces cold spots and the risk of condensation.
- Works where space is limited – Thin 50mm insulation fits behind plasterboard and inside shallow frames. It is also ideal for underfloors where thicker materials will not fit.
- Improves efficiency when layered – On its own, it gives a noticeable improvement. Combined with other insulation layers, it becomes much more effective.
However, 50mm insulation thickness has some limits:
- It cannot meet high-performance targets alone – UK standards for new builds and major upgrades often need more than 50mm thickness insulation.
- Material choice matters more at this depth – At insulation 50mm thickness, high-performance rigid boards outperform softer materials by a wide margin.
