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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.
£51.94£62.33 Ex VATInc VAT£18.03£21.64 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.
£60.18£72.22 Ex VATInc VAT£20.90£25.08 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.
£61.64£73.97 Ex VATInc VAT£21.40£25.68 Per M2 Add to cart -
110mm Celotex XR4110 PIR Insulation Board 2400mm x 1200mm (8′ x 4′) 2.88m2
110mm Celotex XR4110 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.
£49.29£59.15 Ex VATInc VAT£17.11£20.53 Per M2 Get restock alert -
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.
£63.64£76.37 Ex VATInc VAT£22.10£26.52 Per M2 Get restock alert
Floor Insulation Board XR4000
Floor insulation boards form the foundation for warmer, quieter, and more thermally efficient buildings. These boards minimise heat loss and create a stable base for chipboard flooring or underfloor heating systems. They can also be used below screed in solid floor constructions.
What is the floor insulation board?
Floor insulation boards are rigid thermal panels installed beneath floors to reduce heat transfer and improve overall energy performance. They are generally fixed below a floating floor, beneath chipboard flooring, or as part of an underfloor heating setup. This positioning helps prevent heat from escaping downward.
They are commonly made from expanded polystyrene (EPS), extruded polystyrene (XPS), or polyisocyanurate (PIR). These materials are valued for their excellent insulation performance and compressive strength.
What is floor insulation board used for?
Insulating floor boards are mainly used where heat retention and structural comfort matter most. Typical applications for the boards include:
- Suspended timber floors: If proper support (e.g., brackets or battens) is provided, they may be fitted between joists.
- Solid concrete floors: Laid beneath screed or chipboard floors.
- Loft and attic spaces: Perfect under Screwfix loft boards or similar floor systems for light traffic areas.
- Underfloor heating systems: Underfloor heating boards or a thermal base layer underneath pipes and cables.
- Basements, extensions, and conversions: For moisture control and temperature consistency.
For optimal performance, pair them with fire resistant insulation boards or vapour barriers, especially in areas prone to high humidity or requiring added fire protection.
Types of floor insulation board
At Insulation Wholesale, we stock a full range of floor insulation products:
- PIR Floor Insulation Boards: Lightweight, high-performing boards with exceptional R-values. Ideal for underfloor heating and solid floors.
- XPS Floor Insulation Boards: Dense, moisture-resistant panels. Suitable for basements and below-grade use.
- EPS Floor Insulation Boards: Affordable and versatile. Perfect for general flooring applications. Not recommended for high-load floors.
Benefits of floor insulation board
Floor insulation boards provide savings and comfort over time as they are engineered for strength, stability, and performance. Here’s what makes them indispensable in today’s homes and commercial builds:
- Improve energy efficiency: Reduce downward heat loss to lower heating costs.
- Enhance underfloor heating systems: Reflect heat upwards to achieve faster warm-up and more consistent temperatures.
- Reduce noise transfer: Act as a sound buffer between floors when used with acoustic layers, such as underlays and mats. Ideal for multi-storey properties.
- Provide a smooth, stable base: Compatible with chipboard floors, screed, or floating floor systems.
- Moisture and mould resistance: XPS and PIR variants resist damp and maintain performance in humid environments.
- Fire-rated protection: Some floor insulation boards provide additional fire protection when used in approved assemblies.
Why choose our floor insulation board?
Here’s what makes Insulation Wholesale the trusted choice for floor insulation boards in the UK:
- Premium-grade materials from brands like Celotex, Kingspan, and Recticel, all tested to relevant EN and BS standards.
- Extensive selection for solid, suspended, and floating floor applications.
- Compatible with underfloor heating insulation and chipboard flooring systems.
- Technical support to help you select the best insulating boards for your different floor systems.
- Trade pricing, bulk discounts, and reliable UK-wide delivery.
Build from the ground up the smart way with our high-performance floor insulation boards. Laying a floating floor insulation board or preparing underfloor heating insulation? You’ll find the right floor insulation here. Shop now for fast UK delivery and performance built to meet modern building standards.
FAQ
How to install insulation board between floor joists?
- Step: Cut the boards to fit between joists with no gaps.
- Step: Support the insulation with treated timber battens or metal brackets.
- Step: Seal any edges with expanding foam or joint tape to prevent air leakage.
- Step: Install a vapour barrier above before laying your final flooring layer.
How thick should insulation be between floor joists?
For suspended timber floors, 75–100 mm thick insulation is standard. However, it depends on joist depth and target U-value. Thick boards or layered systems can improve efficiency in older or poorly insulated homes.
What is the proper distance between floor joists?
The typical spacing on UK floors is 400 mm or 600 mm in the centre. That means the distance between one joist centre and the next. So it may vary depending on the joist size and load design. To install insulation effectively, confirm joist spacing with your structural drawings or Building Regulations guidance.
