50mm Celotex GA4050 PIR Insulation Board 2400mm x 1200mm

Product Overview

Foil-faced PIR insulation board, measuring 50mm in thickness for use in floors, walls, and roofs. 

Manufactured as part of the GA4000 range, it is intended for general application, meaning it can be confidently specified across a broad spectrum of build-ups without the need for specialist products.

The board consists of a rigid polyisocyanurate (PIR) core faced with low-emissivity foil on both sides. This construction provides excellent thermal resistance, helping to reduce heat loss through the building fabric while also acting as a vapour control layer. 

At 50mm thick, this is the thinnest GA option, providing effective insulation while minimising loss of space.

Features & Benefits

• Thermal conductivity (0.022 W/m·K): Reduces the thickness required to meet U-value targets.
• Low-emissivity foil facings: Reflect radiant heat across cavity air spaces, improving overall efficiency.
• GA4000 range (general application): Suitable for versatile use across roofs, walls, and floors.
• Rigid PIR core: Lightweight yet robust, easy to cut and install with standard tools.
• Moisture resistance: Closed-cell core prevents water uptake and preserves thermal performance.
• Environmental credentials: Zero ODP, low GWP blowing agent, and BRE Green Guide Rating A.
• BBA certified (17/5405, 16/5352): Independent assurance of performance across roofs, walls, and floors.
• Board size 2400 × 1200mm: Supplied in the industry-standard sheet size for insulation, ensuring compatibility across typical build-ups.
• Thickness 50mm: Thinnest GA option, ideal for retrofit and space-constrained projects.
  
  

Applications

• General insulation: Versatile board suitable for a wide range of domestic and commercial applications.
• Beam and block flooring: High-performance PIR boards are installed over the structural floor to provide a continuous thermal barrier beneath sand and cement or liquid screeds. 
• Concrete slab and oversite floors: High compressive strength enables boards to be laid directly over or under ground-bearing slabs to meet specific U-value targets in new-build construction. 
• Suspended timber floors: Rigid boards are cut-to-fit and friction-supported between floor joists to significantly reduce heat loss through ventilated sub-floor voids. 
• Concrete slab overlays: Low thermal conductivity allows for the upgrade of existing concrete floors where minimal thickness is required to maintain room height and door clearances. 
• Underfloor heating systems: Reflective foil facers on both sides of the board enhance the efficiency of underfloor heating by reflecting heat upwards into the living space.
• Timber frame wall insulation: Rigid PIR boards are friction-fitted between timber studs to provide high-performance thermal resistance within a narrow wall profile. 
• Masonry wall dry-lining: Low-conductivity boards are fixed to the internal face of solid or cavity masonry walls to significantly improve thermal retention in retrofit projects. 
• Pitched roof insulation: Versatile 50mm boards are installed between or over rafters to create a high-performance thermal envelope in ventilated or unventilated roof voids. 
• Flat roof insulation: High compressive strength allows for installation beneath a waterproof membrane or over a structural deck to provide a stable, thermally efficient roof covering.
• Summerhouse and garden room insulation: High-performance 0.022 W/mK thermal conductivity provides maximum heat retention within timber stud walls and roof rafters.

Installation Guidance

• Measuring and cutting: Measure the aperture accurately and cut the board using a fine-toothed saw or sharp knife for a tight friction fit.
• Positioning and fixing: Place the board securely against the substrate or between structural members, ensuring no gaps are left between adjacent boards.
• Sealing joints: Apply high-quality aluminium foil tape to all board joints to maintain the integrity of the vapour control layer.
• Mechanical attachment: Use appropriate insulation fixings or adhesive as specified by the project requirements to secure boards to walls or ceilings.
• Fire lining (wall applications): Ensure the insulation used in wall applications is covered with a fire-rated lining, such as 12.5mm plasterboard, to meet safety requirements.

Compliance & Performance

• Thermal conductivity: Achieves a declared Lambda value of 0.022 W/mK in accordance with BS EN 13165.
• Compressive strength: Rated at ≥140 kPa when tested to BS EN 826, making it suitable for floor applications subject to light loads. 
• UK Building Regulations Part L: Helps meet Part L (Fuel and Power) requirements; however, 50mm may require additional layers to meet specific new-build U-value targets.
• UK Building Regulations Part B: Rated as Euroclass E in accordance with BS EN 13501-1; this material is combustible and must be installed behind a fire-rated lining in wall applications.
• UK Building Regulations Part C: Requires the use of a separate Vapour Control Layer (VCL) and taped joints in many applications to prevent interstitial condensation as per Part C (Site preparation and resistance to contaminants and moisture). 
• Environmental impact: Zero Ozone Depletion Potential (ODP) and low Global Warming Potential (GWP) during the manufacturing process.
• Important note: UK Building Regulations vary by project and location; always consult a Building Control Officer or Architect to confirm this thickness meets the legal U-value requirements for your specific build.

What Customers Are Saying

Customers rate the 50mm Celotex highly for internal wall insulation projects where the thinner profile is essential to preserve room dimensions. Reviewers note the boards are easy to cut with a standard saw and fit snugly between battens. The foil facing is praised for its vapour barrier properties, reducing the need for separate membrane installation. Delivery and packaging receive positive mentions across all three reviews.

Summarised by AI from customer reviews.