Free Expanded Polystyrene Insulation Cost Estimator – Updated 2026 Prices
Enter your requirements below to estimate the cost of EPS (expanded polystyrene) insulation in the UK in 2026. Prices cover supply of EPS boards, beads, or cavity fill as selected. Installation costs are shown separately where applicable.
EPS (expanded polystyrene) insulation is one of the most widely used and cost-effective thermal insulation materials in the UK, found in applications ranging from ground floor slabs and cavity walls to flat roofs, external wall render systems, and civil engineering void fill. In 2026, EPS insulation costs in the UK range from approximately £3–£6 per m² for standard white EPS boards at 50mm thickness up to £25–£40 per m² for premium grey graphite EPS at 200mm thickness. Cavity wall EPS bead installation costs approximately £400–£1,200 for a typical UK semi-detached house, making it one of the most cost-effective whole-house energy efficiency measures available.
EPS is manufactured by expanding polystyrene beads with steam inside moulds, creating a rigid closed-cell foam board with excellent thermal insulation properties, low moisture absorption, good compressive strength, and very competitive pricing. The material has been used in UK construction since the 1960s and remains the dominant choice for below-slab floor insulation and ETICS (external insulation and cladding systems) render systems in 2026. The development of grey or graphite EPS — where graphite particles are added to the polystyrene beads before expansion — has dramatically improved the thermal performance of EPS in recent years, with grey EPS achieving lambda values of 0.031–0.034 W/mK compared to 0.038–0.040 W/mK for standard white EPS. This means a thinner board of grey EPS can achieve the same U-value as a thicker white EPS board, which is particularly valuable in applications where board thickness is constrained.
The main cost drivers for EPS insulation in the UK are: board thickness (thicker boards cost more but the cost per unit of thermal resistance is broadly constant); grade and density (higher compressive strength grades cost more); board size and format (standard 1200×2400mm boards are cheapest; cut sizes and special formats attract a premium); quantity ordered (pallet quantities attract significant discounts over pack quantities); and facing or coating (foil-faced, plasterboard-faced, or render-ready boards cost more than plain boards).
EPS, PIR (polyisocyanurate), and mineral wool are the three dominant insulation materials used in UK construction in 2026. Each has distinct cost and performance characteristics:
EPS insulation resources UK 2026: EPS Association UK (EPSA) | BRE Group – Insulation Guidance | GOV.UK – Energy Performance | Planning Portal
The table below provides a comprehensive price guide for EPS insulation supply in the UK in 2026, broken down by product type, thickness, and grade. All prices are indicative mid-range estimates for pallet or large-pack quantities supplied to site. VAT is not included. Installation costs are additional.
| EPS Product | Grade | Thickness | Lambda (W/mK) | Supply Cost per m² | Supply Cost per m² (pallet) |
|---|---|---|---|---|---|
| Standard White EPS Board | EPS 70 | 50mm | 0.038–0.040 | £3.00–£5.00 | £2.50–£4.20 |
| Standard White EPS Board | EPS 100 | 50mm | 0.038–0.040 | £3.50–£5.50 | £2.80–£4.60 |
| Standard White EPS Board | EPS 100 | 100mm | 0.038–0.040 | £6.00–£9.50 | £5.00–£8.00 |
| Standard White EPS Board | EPS 100 | 150mm | 0.038–0.040 | £9.00–£14.00 | £7.50–£12.00 |
| Standard White EPS Board | EPS 150 | 100mm | 0.038–0.040 | £8.50–£13.00 | £7.00–£11.00 |
| Standard White EPS Board | EPS 200 | 100mm | 0.038–0.040 | £11.00–£17.00 | £9.00–£14.50 |
| Grey / Graphite EPS Board | EPS 70 Grey | 50mm | 0.031–0.034 | £5.00–£8.00 | £4.00–£6.50 |
| Grey / Graphite EPS Board | EPS 100 Grey | 100mm | 0.031–0.034 | £8.50–£13.50 | £7.00–£11.50 |
| Grey / Graphite EPS Board | EPS 100 Grey | 150mm | 0.031–0.034 | £12.00–£19.00 | £10.00–£16.00 |
| Grey / Graphite EPS Board | EPS 100 Grey | 200mm | 0.031–0.034 | £16.00–£25.00 | £13.50–£21.00 |
| EPS Cavity Wall Beads | Standard | Full cavity | 0.036–0.040 | £3.00–£6.00/m² wall area | £400–£1,200 per house (installed) |
| EPS Geofoam Block | EPS 70 | 500–1000mm | 0.038–0.040 | £100–£160/m³ | £85–£140/m³ |
| EPS Under-Floor Board | EPS 150 | 100mm | 0.038–0.040 | £8.00–£12.50 | £6.50–£10.50 |
| EPS Flat Roof Board | EPS 100 | 100mm | 0.038–0.040 | £7.50–£11.50 | £6.00–£9.50 |
| Foil-Faced EPS Board | EPS 100 | 100mm | 0.038–0.040 | £9.00–£14.00 | £7.50–£12.00 |
| Plasterboard-Faced EPS | EPS 70 | 50mm EPS + 12.5mm PB | 0.038–0.040 | £12.00–£19.00 | £10.00–£16.00 |
All prices are indicative mid-range UK 2026 supply estimates, excl. VAT. Pallet prices apply to full pallet orders (typically 40–60 boards per pallet). Small pack / merchant prices are typically 15–25% higher than pallet prices. Prices can vary significantly between suppliers — always request quotes from at least three suppliers for large orders.
The following additional costs are commonly encountered on EPS insulation projects in 2026 and are typically quoted separately by installers or specialist subcontractors.
| Extra / Service | Typical Cost Range (2026) | Notes |
|---|---|---|
| EPS board installation – below floor slab | £3–£8/m² labour | Boards laid directly on blinding; low-skill but labour-intensive for large areas; often done by groundworks contractor |
| EPS board installation – external wall (ETICS) | £15–£35/m² labour | Includes adhesive, mechanical fixings (EWI plugs), and setting out; specialist EWI contractor required |
| EPS board installation – internal dry-lining | £8–£18/m² labour | Boards adhered to masonry wall with dot-and-dab or continuous adhesive; includes cutting and fitting |
| EPS cavity wall bead installation | £400–£1,200 per house | Specialist contractor; drilled, injected, and sealed; must be CIGA-registered installer |
| Render system over EPS (ETICS) | £25–£55/m² supply and apply | Base coat + reinforcement mesh + topcoat silicone or mineral render; requires specialist EWI system |
| Adhesive / EPS bonding mortar | £0.80–£2.00/m² | Per m² of board area; EWI-specific adhesive for external systems; dot-and-dab for internal |
| EWI mechanical fixings (EWI plugs) | £0.30–£0.80 per fixing | Typically 6–8 fixings per m² for external wall insulation; polypropylene plug with long screw |
| EPS board cutting service | £0.50–£2.00/m² surcharge | Hot-wire cut to non-standard sizes; charged per m² of cut area or per linear metre of cut |
| Pallet delivery (UK mainland) | £40–£100 per pallet | EPS boards are bulky; full pallet loads (typically 20–40 m² coverage per pallet) delivered by flatbed |
| EPS screed over insulation (liquid screed) | £18–£35/m² | Anhydrite or cementitious liquid screed poured over EPS floor insulation; most common in new build |
| Sand-cement screed over insulation | £14–£28/m² | Traditional screed over EPS floor boards; 65–75mm depth; includes edge insulation strip |
| EPS edge insulation strip (perimeter) | £1.50–£4.00 per linear metre | Compressible EPS strip at slab perimeter to prevent thermal bridging; required by Part L Building Regs |
| CIGA guarantee (cavity wall insulation) | Included with CIGA-registered installer | 25-year guarantee from Cavity Insulation Guarantee Agency; required for any government-backed scheme |
| SAP / thermal modelling update | £150–£600 | Updating the Energy Performance Certificate (EPC) after insulation installation; required for some schemes |
The most commonly purchased EPS product — 100mm EPS 100 board for ground floor slab insulation — costs approximately £5–£8/m² on pallet quantities in 2026. Cavity wall EPS bead installation for a typical UK semi-detached house costs £400–£900, often part-funded through energy efficiency grants.
EPS grades (EPS 70, EPS 100, EPS 150, EPS 200) refer to the compressive stress at 10% deformation in kPa, not the density in kg/m³. Higher grades are denser, stronger, and slightly better insulating (lower lambda). For domestic ground floor slab insulation, EPS 100 is the standard minimum; EPS 150 is recommended for heavily loaded commercial floors.
Grey (graphite) EPS achieves a lambda of 0.030–0.034 W/mK vs 0.038–0.040 W/mK for standard white EPS — approximately 15–20% better thermal performance. This means you can achieve the same U-value with 15–25mm less thickness using grey EPS, at a cost premium of approximately 20–40% over white EPS of the same thickness.
EPS insulation installed in a dwelling by a VAT-registered installer typically qualifies for the 5% reduced rate of VAT (energy-saving materials). Supply-only purchases and commercial or non-domestic installations are subject to 20% standard rate VAT. The 5% rate was confirmed until at least 2027 under current UK legislation. Always confirm the applicable VAT rate with your supplier or installer.
Part L of the Building Regulations (Conservation of Fuel and Power) specifies minimum insulation requirements for new builds and extensions in England. For new dwellings in 2026, ground floors require a minimum U-value of 0.13 W/m²K, walls 0.18 W/m²K, and roofs 0.11 W/m²K. Achieving these values typically requires 100–150mm of EPS under floor slabs and 80–150mm of EPS on external walls (ETICS systems).
Standard EPS is combustible and is classified as Euroclass E (combustible, limited flame spread) under EN 13501-1. For applications on buildings over 11m in height (and in some cases over 18m), combustible insulation is restricted under UK fire safety regulations following the 2017 Grenfell Tower fire. EPS should not be used on high-rise residential facades without appropriate fire-rated cavity barriers and facade engineering. For most low-rise domestic applications, EPS with flame-retardant additives is acceptable.
EPS has very low water absorption (typically less than 1% by volume after 28 days immersion) and is resistant to moisture degradation. Unlike some other insulation materials, EPS retains essentially all of its thermal performance when wet, making it ideal for below-slab, cavity wall, and inverted flat roof applications where moisture exposure is unavoidable. EPS is also resistant to freeze-thaw cycles, important for external and ground-contact applications in the UK.
EPS boards are always cheaper per m² when ordered in full pallet quantities vs small pack quantities purchased from a builders’ merchant. Pallet pricing is typically 15–30% cheaper than merchant pack pricing. For any project over 50 m², it is worth contacting EPS manufacturers or specialist insulation suppliers directly for pallet pricing. Minimum pallet orders are typically 40–80 m² coverage depending on board thickness.
EPS is 100% recyclable and the UK has an established network of EPS recycling collection points operated through the EPSA (EPS Association UK). Cut-offs, broken boards, and packaging EPS can all be recycled. Recycled EPS is reprocessed into new EPS products, composite timber products, and concrete aggregate (Liapor/Lytag type). Using recycled EPS contributes to BREEAM and LEED sustainability credits.
EPS cavity wall bead insulation is eligible for UK government energy efficiency grants in 2026 under the Great British Insulation Scheme (GBIS) and ECO4 scheme. Eligible households (based on EPC rating and income criteria) may receive fully funded or heavily subsidised cavity wall insulation. Contact your energy supplier or the government’s Simple Energy Advice service to check eligibility.
Standard EPS board sizes in the UK are 1200mm × 2400mm (2.88 m² per board) and 1200mm × 600mm (0.72 m² per board). Some suppliers also offer 2400mm × 1200mm in tongue-and-groove profiles for flooring applications. Non-standard sizes can be cut to order with a hot-wire cutter. Always calculate board coverage allowing for at least 5% cutting waste.
EPS insulation prices vary significantly between suppliers — variation of 20–40% for equivalent specifications is common. Always compare quotes on a like-for-like basis, confirming the EPS grade (compressive strength), density, lambda value, board dimensions, and any relevant certifications (BBA, LABC, or manufacturer’s third-party test reports). Specialist insulation suppliers typically offer better pricing than general builders’ merchants for large orders.
The table below shows indicative U-values achievable with different thicknesses of EPS insulation in typical UK construction elements. U-values shown are for the EPS layer only in an idealised construction — actual element U-values depend on the full construction build-up including structural layers, finishes, and surface resistances. All calculations assume lambda 0.038 W/mK for standard white EPS and lambda 0.032 W/mK for grey EPS.
| EPS Thickness | EPS Type | Thermal Resistance (m²K/W) | Indicative Floor U-value | Indicative Wall U-value | Part L 2026 Compliance? |
|---|---|---|---|---|---|
| 50mm | White EPS (λ 0.038) | 1.32 | ~0.45 W/m²K | ~0.38 W/m²K | No – below minimum |
| 75mm | White EPS (λ 0.038) | 1.97 | ~0.32 W/m²K | ~0.28 W/m²K | Partial – walls may comply |
| 100mm | White EPS (λ 0.038) | 2.63 | ~0.26 W/m²K | ~0.22 W/m²K | Partial – walls comply; floor marginal |
| 100mm | Grey EPS (λ 0.032) | 3.13 | ~0.22 W/m²K | ~0.19 W/m²K | Walls comply; floor marginal |
| 150mm | White EPS (λ 0.038) | 3.95 | ~0.18 W/m²K | ~0.16 W/m²K | Floors and walls comply |
| 150mm | Grey EPS (λ 0.032) | 4.69 | ~0.15 W/m²K | ~0.14 W/m²K | Yes – complies comfortably |
| 200mm | White EPS (λ 0.038) | 5.26 | ~0.14 W/m²K | ~0.13 W/m²K | Yes – floors and walls comply |
| 200mm | Grey EPS (λ 0.032) | 6.25 | ~0.12 W/m²K | ~0.11 W/m²K | Yes – exceeds requirements |
| 250mm | Grey EPS (λ 0.032) | 7.81 | ~0.10 W/m²K | ~0.09 W/m²K | Yes – passive house level |
| 300mm | Grey EPS (λ 0.032) | 9.38 | ~0.08 W/m²K | ~0.08 W/m²K | Yes – exceeds all UK standards |
Building Regulations Part L (England) 2026 minimum U-value targets: ground floor 0.13 W/m²K, walls 0.18 W/m²K, roof 0.11 W/m²K for new dwellings. Actual U-values achieved in full construction elements will differ from the EPS-only values shown above. Always carry out a full U-value calculation for your specific build-up using approved software or CIBSE methods before finalising insulation specifications.
EPS insulation costs in the UK in 2026 range from approximately £2.50–£4.20/m² for standard white EPS 100 boards at 50mm thickness on pallet quantities, up to £16–£25/m² for 200mm grey graphite EPS on pallet quantities. The most commonly specified product — 100mm EPS 100 white board for ground floor insulation — costs approximately £5–£8/m² on pallet quantities, or £6–£10/m² from a builders’ merchant in small quantities. Cavity wall EPS bead insulation installed in a typical UK semi-detached house costs approximately £400–£1,200 fully installed, often heavily subsidised through energy efficiency schemes.
The numbers in EPS grade names (EPS 70, EPS 100, EPS 150, EPS 200) refer to the compressive stress at 10% deformation, measured in kilopascals (kPa). This is a measure of the board’s stiffness and load-bearing capacity, not its thermal performance. EPS 70 (approximately 15 kg/m³ density) is suitable for wall insulation and light-load applications where compressive strength is not critical. EPS 100 (approximately 20 kg/m³) is the standard specification for domestic ground floor slab insulation under concrete or screed. EPS 150 (approximately 25 kg/m³) is specified for heavily loaded floors, commercial applications, and below-slab insulation in industrial buildings. EPS 200 (approximately 30 kg/m³) is used for road sub-base insulation, industrial floors, and geofoam applications. Higher grade EPS costs more per m² but has slightly better thermal performance (marginally lower lambda) due to its higher density.
For most UK domestic ground floor insulation applications in 2026, EPS 100 provides better value than PIR (polyisocyanurate). EPS costs approximately 40–60% less per m² than PIR for the same area, and while PIR has a better lambda value (0.022–0.026 W/mK vs 0.038 W/mK for EPS), the floor depth saving from PIR’s better performance (approximately 40–50mm thinner for the same U-value) is only significant where floor height is critically constrained — for example, when retrofitting insulation under an existing floor without raising the floor level significantly. In new build applications where floor build-up depth is not constrained, the additional cost of PIR over EPS rarely delivers sufficient energy savings to justify the upfront premium. EPS also has better long-term lambda stability than some PIR products.
To comply with Part L of the Building Regulations in England in 2026, a new dwelling ground floor must achieve a U-value of 0.13 W/m²K or better. Achieving this with EPS insulation alone in a typical ground-bearing slab construction requires approximately 150mm of standard white EPS 100 (lambda 0.038 W/mK) or approximately 120–130mm of grey EPS (lambda 0.032 W/mK), depending on the size and shape of the floor (larger floors have better edge-to-area ratios). Where the floor perimeter is large relative to the area (e.g. a narrow extension), more insulation depth may be needed to compensate for edge heat loss. Always carry out a full SAP or simplified U-value calculation for your specific floor dimensions before finalising the insulation specification.
Yes — EPS is one of the most widely used external wall insulation materials in the UK in 2026, particularly as the insulation layer in ETICS (external thermal insulation composite system) render systems. In a typical ETICS installation, EPS boards (usually EPS 70 or EPS 100 grey) are adhesive-fixed and mechanically fixed to the outer face of the masonry wall, and then covered with a reinforced base coat and decorative render finish. This creates a highly effective insulated facade that eliminates cold bridging and adds substantial thermal mass to the building. The typical specification for Part L compliance on a masonry wall is 80–120mm of EPS in an ETICS system. Full ETICS system supply and installation costs approximately £50–£100/m² depending on the EPS thickness, render specification, and installer.
Grey EPS (also called graphite EPS or silver EPS) is expanded polystyrene insulation in which graphite particles are incorporated into the polystyrene beads before expansion. The graphite acts as an infrared reflector and absorber, reducing the radiative component of heat transfer through the foam and lowering the effective lambda value to approximately 0.030–0.034 W/mK compared to 0.038–0.040 W/mK for standard white EPS. In practical terms, this means grey EPS is approximately 15–25% more thermally efficient per millimetre of thickness. It typically costs 20–40% more per m² than equivalent white EPS. The extra cost is generally worth it when board thickness is constrained (e.g. cavity wall fill, shallow floor retrofit, or slim-profile ETICS systems), but the payback period from energy savings alone may be long in a low-energy-cost scenario. For new build applications where thickness is not constrained, the decision is primarily one of achieving compliance with minimum material.
Yes — EPS cavity wall bead insulation is eligible for UK government energy efficiency grants in 2026. The two main schemes are: Great British Insulation Scheme (GBIS) — available to households with an EPC rating of D–G and meeting income criteria; and ECO4 (Energy Company Obligation) — targeting low-income and fuel-poor households, funded through energy suppliers. Eligible households may receive fully funded cavity wall insulation at no cost. Even households that do not qualify for full funding may receive a partial subsidy. To check eligibility, contact your gas or electricity supplier, or visit the GOV.UK Simple Energy Advice website. Ensure any installer is registered with CIGA (Cavity Insulation Guarantee Agency) to receive the standard 25-year installation guarantee.
Standard EPS insulation is safe to use in buildings when installed correctly and in appropriate applications. Key safety considerations are: Fire: EPS is combustible and classified Euroclass E. For low-rise domestic construction (under 11m), EPS with flame-retardant additives is generally acceptable in ETICS and floor/roof applications. For mid-rise (11–18m) and high-rise (above 18m) buildings, the use of combustible insulation on facades is subject to significant restrictions under UK fire safety regulations and ADB (Approved Document B). Always confirm fire safety compliance with your building control officer. Indoor air quality: EPS does not off-gas volatile organic compounds (VOCs) or formaldehyde once manufactured and is safe for use in occupied buildings. Rodents: EPS can be damaged by rodents if exposed — ensure boards are fully covered by render, screed, or other protective finishes.
To calculate the quantity of EPS insulation required, follow these steps. First, measure the total area to be insulated in m². For a floor, this is the floor area; for walls, it is the wall area minus windows and doors. Add a wastage allowance of 5–10% for cutting, fitting around obstacles, and damaged boards. Divide the total area (including wastage) by the area of a single board — standard EPS boards are 1200mm × 2400mm = 2.88 m² per board. Round up to the nearest whole board. For example, for a 50 m² floor with 8% wastage allowance: 50 × 1.08 = 54 m² ÷ 2.88 m²/board = 18.75, rounded up to 19 boards. Order slightly more than you think you need — reordering a small quantity of boards later attracts significant per-board cost premiums.
EPS insulation has an exceptionally long service life when correctly installed and protected from UV light and physical damage. In below-slab, cavity wall, and inverted roof applications, EPS can be expected to retain its thermal performance essentially indefinitely — studies of EPS cavity wall insulation installed in the 1970s have found no significant degradation in thermal performance after 40+ years. The material is chemically inert, does not absorb moisture, and does not support biological growth. Its one vulnerability is UV degradation — prolonged exposure to sunlight causes surface yellowing and embrittlement — but this is irrelevant in all correctly detailed applications where EPS is covered by render, screed, or other finishes. EPS insulation comes with manufacturer’s warranties of 25–50 years in most applications.
For supply-only EPS boards, the best sources in the UK in 2026 are specialist insulation distributors (who offer pallet pricing and can advise on specification), direct from EPS manufacturers (Knauf, Jablite, Springvale, Polyfoam) for large orders, or from builders’ merchants for smaller quantities. Always confirm the EPS grade, density, lambda value, and any third-party certification (BBA Agrément Certificate) before ordering. For ETICS installation, look for installers approved by the system manufacturer (e.g. Baumit, Sto, Weber, Parex) — using an approved installer is essential for warranty validity. For cavity wall EPS bead installation, only use a CIGA-registered installer (Cavity Insulation Guarantee Agency) to ensure the 25-year installation guarantee is valid. Check reviews on Checkatrade or TrustATrader and obtain at least three comparable written quotations.
Additional EPS insulation resources 2026: EPS Association UK (EPSA) | CIGA – Cavity Insulation Guarantee Agency | GOV.UK – Energy Efficiency Grants | BRE Group – Building Research | GOV.UK Building Regulations