Description
Part L 2025 and Future Homes Standard compliance thickness — 150 mm graphite EPS at λD 0.031 W/mK delivers RD 4.80 m²K/W, the depth that drops typical UK masonry walls to 0.18–0.21 W/m²K and clears the 0.26 W/m²K new-build elemental target with comfortable headroom. Four boards per pack, 2.0 m² coverage, dispatched next working day from our Southampton warehouse.
What EPS Grafit 150 mm Does in a UK EWI System
The Genderka EPS 031 Fasada Extra Plus 150 mm is a graphite-enhanced expanded polystyrene insulation board with declared thermal conductivity λD 0.031 W/mK and thermal resistance RD 4.80 m²K/W. Certified to EN 13163, it serves as the primary insulation layer in enhanced-performance EWI systems on new-build, deep-renovation, and near-zero energy projects up to 18 m in height. It sits within the wider graphite EPS insulation board range as the Part L 2025 and Future Homes Standard compliance thickness — the depth at which standard UK masonry walls reach 0.18–0.21 W/m²K, comfortably below the 0.26 W/m²K new-build elemental target.
Specifiers reach for 150 mm when the project demands enhanced fabric performance, not just baseline retrofit compliance. New-build fabric-first design, PAS 2035 whole-house retrofit, Passive House pre-certification, and local authority deep-renovation programmes all converge on this thickness as the practical entry point for sub-0.22 W/m²K wall U-values on standard masonry constructions.
Why Specifiers Choose EPS Grafit 150 mm for UK Walls
- Part L 2025 and Future Homes Standard pathway — assembly U-value lands at approximately 0.18–0.21 W/m²K on 215 mm solid brick, clearing the 0.26 W/m²K new-build elemental target with measurable future-proofing headroom.
- RD 4.80 m²K/W from a 150 mm depth — graphite bead chemistry delivers roughly 20 % better insulation than white EPS at the same thickness, saving over 35 mm of total build-up depth on every square metre of wall.
- Passive House pre-certification compatible — when combined with thermally broken fixings and optimised junction detailing, the 150 mm depth contributes credibly to the ≤ 0.15 W/m²K fabric target without moving to 180–200 mm thicknesses.
- Self-supporting board rigidity at depth — BS100 bending strength keeps the board flat when leant against the wall face between adhesive application and mechanical fixing, no bowing or deflection during the 24-hour cure window.
- Standardised installation across the EWI range — bonds with the same adhesives, basecoats, and meshes as thinner variants; only the fixing plug length changes (LTX 180 mm replaces the LTX 140 mm used at 100 mm).
- EN 13163 CE-marked with full Declaration of Performance — every pack traceable to the originating Genderka facility, supporting Building Control evidence packs, PAS 2035 retrofit coordinator records, and SAP assessor documentation.
- Direct from Southampton warehouse — pallet quantities for new-build and deep-renovation programmes typically dispatched next working day, with consolidated EWI system orders shipped on a single delivery.
Thermal Specifications — λ, U-Value, Reaction to Fire
| Property | Value |
|---|---|
| Declared thermal conductivity (λD) | 0.031 W/mK |
| Thermal resistance (RD) at 150 mm | 4.80 m²K/W |
| Indicative wall U-value (215 mm solid brick + 150 mm) | 0.18–0.21 W/m²K, subject to calculation |
| Reaction to fire (EN 13501-1) | Euroclass E |
| Classification string | EPS EN 13163 T1-L2-W2-Sb2-P5-BS100-DS(N)2-DS(70,-)2-TR100 |
Under current Approved Document B guidance, Euroclass E EPS is permitted within EWI build-ups on residential buildings below 18 m where the project fire strategy specifies horizontal mineral wool fire barriers at each floor level and around openings. For buildings above 18 m or where the project fire strategy requires non-combustible insulation throughout, switch the specification to the mineral wool insulation range — the trade-offs between EPS and mineral wool at enhanced thicknesses are set out in the graphite EPS vs mineral wool 2026 facade guide.
Physical Specifications — Density, Strength, Dimensions
| Property | Value |
|---|---|
| Manufacturer | Genderka Sp. z o.o. |
| Range | EPS 031 Fasada Extra Plus |
| Thickness | 150 mm |
| Board size | 1000 mm × 500 mm |
| Coverage per board | 0.50 m² |
| Boards per pack | 4 |
| Pack coverage | 2.0 m² |
| Density | 15 kg/m³ |
| Bending strength | ≥ 100 kPa (BS100) |
| Tensile strength perpendicular to faces | ≥ 100 kPa (TR100) |
| Dimensional stability (normal) | ± 0.2 % (DS(N)2) |
| Standard | EN 13163:2012+A1:2015 |
Where EPS Grafit 150 mm Performs Best — Wall Types and Build-Up
The 150 mm graphite EPS board is the compliance-headroom thickness for projects where current and anticipated UK fabric standards meet at one specification line. Three project types account for the majority of UK use cases at this depth.
New-Build Fabric-First Design
Architects specifying a fabric-first route to the Future Homes Standard reach for 150 mm of graphite EPS as the primary wall insulation layer. The resulting wall U-value of 0.18–0.21 W/m²K reduces the dwelling emission rate's reliance on mechanical ventilation and heat-recovery systems, simplifying the services specification and lowering long-term maintenance complexity for the end occupier.
PAS 2035 Whole-House Retrofit
Properties undergoing a co-ordinated whole-house retrofit to EPC band A or B benefit from the substantial R-value that a 150 mm external layer adds to the assembly. Combined with loft, floor, and window upgrades, this thickness moves the wall element well inside the enhanced fabric targets used in PAS 2035 medium-term improvement plans and supports retrofit coordinator sign-off on the fabric-first hierarchy.
Passive House and Near-Zero Energy Builds
The 150 mm board is the entry-level wall thickness for projects pursuing Passive House pre-certification or near-zero energy performance. Wall-element U-values at this depth contribute credibly towards the ≤ 0.15 W/m²K fabric target when paired with thermally broken fixings and optimised reveal, soffit, and junction detailing.
How EPS Grafit 150 mm Fits Into a Full EWI System
Boards bond to the prepared substrate with a circumferential-and-spot adhesive bead from the EPS adhesives and basecoats range, aiming for a minimum 40 % contact area to satisfy wind-load design under BS EN 1991-1-4. At 150 mm board depth maintain a continuous perimeter bead at least 30 mm wide and three central spots each at least 100 mm in diameter — full-face support matters more at this thickness because the longer lever arm transfers more force to the adhesive layer during wind events.
After a minimum 24-hour adhesive cure, secure with 6–8 mechanical fixings per m² from the insulation fixing accessories range. The matching fixing plug for 150 mm boards on standard masonry is the LTX 180 mm polystyrene fixing plug, providing 25–30 mm of embedment beyond the board and adhesive layer. Rasp the outer face to create a basecoat key, then apply reinforcing basecoat with embedded fibreglass mesh and finish with the project's specified render system. The full layer-by-layer sequence, drying intervals, and tie-in detailing for reveals and soffits are mapped in the EWI system build-up layers explained guide, where the dependencies that determine programme length are set out for each stage of the build.
How EPS Grafit 150 mm Compares to Sibling EPS Boards
| Property | 100 mm Grafit (retrofit standard) | 150 mm Grafit (this board) | 160 mm Grafit (deeper retrofit) |
|---|---|---|---|
| Thickness | 100 mm | 150 mm | 160 mm |
| λD | 0.031 W/mK | 0.031 W/mK | 0.031 W/mK |
| RD | 3.20 m²K/W | 4.80 m²K/W | 5.15 m²K/W |
| Indicative U-value (215 mm brick) | 0.27–0.30 W/m²K | 0.18–0.21 W/m²K | 0.17–0.19 W/m²K |
| Pack coverage | 3.0 m² | 2.0 m² | 1.5 m² |
| Matched fixing plug | LTX 140 mm | LTX 180 mm | LTX 200 mm |
| Typical specification | Semi-detached retrofit compliance | Part L 2025 / Future Homes pathway | Deep renovation, max-depth retrofit |
Choose 150 mm when the project targets enhanced fabric performance, new-build Future Homes Standard readiness, or PAS 2035 whole-house retrofit to EPC band A or B. Step down to 100 mm only when the brief is baseline Approved Document L retrofit compliance at 0.30 W/m²K; step up to 160 mm when the project pushes for the lowest achievable wall U-value within standard EWI build-up depths. The calculation method behind these U-value bands is detailed in the U-value calculation and wall insulation thickness guide.
How EPS Grafit 150 mm Performs in UK Weather — Moisture, Frost, Wind Loads
Graphite EPS has a closed-cell structure with very low water absorption (W2 classification under EN 13163), allowing the board to maintain declared thermal performance through the wet UK heating season when installed within a correctly detailed render or EWI system. Freeze-thaw cycling does not degrade the bead structure, and the material is unaffected by typical UK winter temperatures.
Wind-load resistance at 150 mm depth depends on the combined adhesive and mechanical fixing specification more than on the board itself. On standard UK exposure zones the recommended 6–8 plugs per m², combined with full-perimeter adhesive contact, delivers reliable retention to BS EN 1991-1-4 design pressures. On exposed coastal or upland sites, increase fixing density to 8–10 per m² and verify with the project structural engineer — the longer fixing shank used at this thickness transmits more lever-arm force to the substrate, so embedment depth and substrate quality matter more than at 80–100 mm. Condensation risk on solid-wall retrofits at enhanced insulation depths is covered in the dew point and condensation risk guide, where the physics behind thicker insulation actually lowering interstitial risk on most masonry constructions is set out in full.
Handling and Storage on Site
At 150 mm and 15 kg/m³ density each board weighs roughly 1.125 kg, still comfortable for single-handed positioning at scaffold height. Store packs flat on a level surface under opaque sheeting — at this thickness the thermal mass of the board means the steel-grey graphite face reaches surprisingly high temperatures in direct sunlight, softening the bead structure faster than thinner variants. The pro-tips below capture the handling discipline that pays back across a new-build or deep-renovation programme.
- Stage packs per scaffold lift in fix sequence — pre-stage from the base track upward so installers reach for the next board in order rather than searching the platform. On large-area new-build elevations this typically saves 15–25 minutes of platform-clearing time per lift.
- Use a long-blade hot-wire cutter for 150 mm depth — gives the cleanest and fastest cut face at this thickness. A fine-tooth handsaw works but generates more dust and demands a steady, straight draw to avoid a wavy cut edge that compromises butt-joint tightness.
- Rasp the bonding face before adhesive application — the factory skin on graphite EPS benefits from a mechanical key, and at 150 mm a strong adhesive bond is especially important because the longer fixing shanks transmit more lever-arm force during wind events.
- Use a depth stop on the drill at 180 mm fixing length — accurate, consistent embedment across the entire façade is a step worth getting right. A 5-second drill-stop adjustment per fixing protects long-term wind-load performance across the full elevation.
Certifications and Compliance — BBA, EN, Reaction to Fire
- EN 13163:2012+A1:2015 — harmonised European standard for factory-made expanded polystyrene products, covering declared thermal conductivity, dimensional tolerances, and mechanical strength properties.
- Reaction to fire — Euroclass E (EN 13501-1) — suitable for EWI systems on residential buildings below 18 m where the project fire strategy specifies horizontal fire barriers at each floor level, under current Approved Document B guidance.
- CE marking and Declaration of Performance — every pack traceable to the originating Genderka facility, supporting Building Control evidence packs, PAS 2035 retrofit coordinator records, and SAP assessor documentation.
- Part L and Future Homes Standard pathway — at RD 4.80 m²K/W the board typically delivers wall U-values of 0.18–0.21 W/m²K on 215 mm solid brick, comfortably below both the Approved Document L retrofit target (0.30 W/m²K) and the new-build elemental target (0.26 W/m²K), subject to project-specific calculation. The wider regulatory trajectory is set out in the Future Homes Standard 2026 guide.
All thermal values stated are declared (λD, RD) per EN 13163 and manufacturer technical data sheet (Genderka karta techniczna nr W31FEP, July 2024). Actual installed U-values depend on wall construction, adhesive coverage, fixing thermal bridging, and the complete EWI system build-up. Verify system-level U-value calculations with a competent energy assessor or Building Control body before specifying.
Is EPS Grafit 150 mm Right for Your Project?
- Best fit: new-build Future Homes Standard pathway, PAS 2035 whole-house retrofit to EPC band A or B, or Passive House pre-certification.
- Baseline retrofit alternative: projects targeting Approved Document L 0.30 W/m²K retrofit compliance favour the 100 mm Grafit board at reduced material cost and slimmer build-up.
- Maximum-depth retrofit alternative: projects pushing for the lowest achievable wall U-value below 0.20 W/m²K step up to the 160 mm Grafit board at R 5.15 m²K/W.
- Fire-strategy alternative: buildings above 18 m or projects requiring non-combustible insulation throughout — specify from the mineral wool insulation range.
- Bundle route: new-build and deep-renovation programmes benefit from sourcing all components through a single EWI system order with consolidated delivery.
What to Order Next — Pack Sizes, Lead Times, Compatible Components
Confirm the surveyed wall area in m², divide by 2.0 m² per pack, and add 5–10 % for cutting waste around reveals, soffits, and service penetrations. Pair each pallet of 150 mm boards with sufficient adhesive and basecoat from the adhesives and basecoats range (typical demand 4–5 kg/m² for the adhesive layer and 4 kg/m² for the basecoat layer), plus the LTX 180 mm fixing plug at 6–8 fixings per m². Pallet quantities for new-build and deep-renovation programmes are typically dispatched next working day from our Southampton warehouse on consolidated EWI deliveries.
For architects, retrofit coordinators, and main contractors, consolidated take-off sheets, per-m² pricing, and split deliveries phased to scaffold rotation are available on request via the trade desk before the first pallet leaves the warehouse.
FAQ — EPS Grafit 150 mm Thickness, Coverage, Installation
How many packs does a typical detached new-build require?
A three-bedroom detached new-build with approximately 100–120 m² of external wall area (after deducting windows and doors) requires roughly 55–65 packs of 4 boards, including 5–10 % for cutting waste around reveals, soffits, and service penetrations. For retrofit projects with smaller exposed wall areas, order quantities scale proportionally against the measured site survey.
Does 150 mm meet Part L and Future Homes Standard wall U-value targets?
On a typical 215 mm solid brick wall the assembly U-value lands at approximately 0.18–0.21 W/m²K, comfortably below both the Approved Document L new-build elemental target (0.26 W/m²K) and the retrofit target (0.30 W/m²K), subject to project U-value calculation. This thickness aligns with the enhanced fabric performance anticipated under the Future Homes Standard, providing a specification that is compliant today and prepared for the tighter requirements when the standard takes full effect.
Which fixing plug pairs with the 150 mm board on standard masonry?
The LTX 180 mm polystyrene fixing plug provides the correct embedment for a 150 mm board on standard brick or block substrates, delivering 25–30 mm beyond the board and adhesive layer. Install 6–8 fixings per m² in the pattern specified for the project's wind-load zone, with fixings positioned at board junctions and across the field area for even load distribution. Use a depth stop on the drill to ensure consistent embedment across the full façade.
Is 150 mm sufficient for Passive House certification?
The 150 mm board is the entry-level wall thickness for Passive House pre-certification. Reaching the ≤ 0.15 W/m²K fabric target typically requires the 150 mm depth combined with thermally broken fixings, optimised reveal and soffit detailing, and verified junction psi-values. Projects pursuing full Passive House certification on standard masonry constructions may step up to 180 mm or 200 mm depending on the certifier's full thermal model.
What is the expected service life within an EWI render system?
Within a correctly detailed render system with intact basecoat and finish, graphite EPS maintains its declared thermal performance throughout the EWI system's typical 30+ year design life. Periodic visual inspection of the render surface for impact damage and prompt repair of any breaches preserves long-term insulation performance.
Is the 150 mm board suitable for buildings above 18 m?
For residential buildings above 18 m, current Approved Document B guidance and Building Safety Act 2022 provisions typically call for non-combustible (Euroclass A2-s1,d0 or A1) insulation throughout the façade. Switch the specification to the mineral wool insulation range for these projects, subject to the project fire strategy.