Polystyrene EPS Grafit 180 mm — Graphite Insulation Board for Part L Compliance, λ 0.031 W/mK

Genderka EPS 031 Fasada Extra Plus 180 mm is a graphite-enhanced expanded polystyrene insulation board delivering a declared thermal conductivity of λD 0.031 W/mK and thermal resistance of R 5.80 m²K/W — a high-performance thickness that achieves wall-assembly U-values approaching the Passive House fabric threshold on standard UK masonry constructions. Each board measures 1000 × 500 mm and is supplied in packs of 3 boards covering 1.5 m², keeping individual pack dimensions manageable at this substantial board depth. Browse the full selection of graphite EPS insulation boards to match every zone of your façade build-up to the right thickness.

Certified to EN 13163:2012+A1:2015 with the classification string T1-L2-W2-Sb2-P5-BS100-DS(N)2-DS(70,-)2-TR100, this board shares the same graphite bead technology and mechanical properties as every variant in the Genderka EPS 031 Fasada Extra Plus family. At 180 mm the board delivers wall-assembly U-values of approximately 0.15–0.17 W/m²K on standard 215 mm solid brick — substantially below the 0.26 W/m²K new-build elemental target in Approved Document L and within striking distance of the ≤ 0.15 W/m²K fabric target that Passive House projects typically require for external walls. For context on how evolving UK energy standards influence insulation thickness choices, see the Future Homes Standard 2026 and its insulation requirements.

Key Benefits and Performance Advantages

Near-Passive-House Performance From a Single Board Layer

• R 5.80 m²K/W — Approaching ≤ 0.15 W/m²K on Standard Masonry: On a typical 215 mm solid brick wall, 180 mm of graphite EPS brings the assembly U-value to approximately 0.15–0.17 W/m²K. On well-pointed brickwork with lower conductivity (≤ 0.70 W/mK), the assembly reaches or touches the 0.15 W/m²K Passive House wall target — delivering near-Passive fabric performance from a single-layer graphite EPS installation.
• Graphite-Enhanced λ 0.031 W/mK: Integrated graphite particles reflect infrared radiation within each cell, delivering approximately 20 % better insulation than standard white EPS of the same thickness. A 180 mm graphite board matches the thermal performance of roughly 225 mm of white EPS, saving over 45 mm of build-up depth — a significant advantage on projects where total façade projection affects planning consent and architectural proportions.

Specified for the Most Ambitious UK Projects

• Passive House and Energiesprong Programmes: The 180 mm thickness aligns with the insulation depths used in UK Energiesprong whole-house retrofit programmes and Passive House new-build specifications, where wall-element U-values of ≤ 0.15 W/m²K form part of an integrated fabric-and-services design targeting near-zero heating demand.
• Social Housing Decarbonisation and Net-Zero Pathways: Local authorities and housing associations pursuing net-zero carbon commitments benefit from the substantial R-value that 180 mm provides, supporting the leap from EPC band D directly to band A on coordinated whole-house upgrades.

Rigid and Self-Supporting at Depth

• Bending Strength BS100 (≥ 100 kPa): Each board maintains its shape during handling and positioning at scaffold height. At 180 mm the board is thick and rigid, standing upright against the wall face without bowing — practical for staged fixing where boards are temporarily positioned before adhesive and mechanical fixing operations.
• Tensile Strength TR100 (≥ 100 kPa): Adhesive bonds securely to the graphite-EPS surface, and the board's tensile integrity ensures that the long mechanical fixing shanks required at this depth transfer wind loads evenly without localised pull-through around the fixing head.

Compact Packs Despite Substantial Depth

• 3 Boards per Pack (1.5 m²): Each pack remains physically manageable for two-person lift onto scaffold platforms. At 15 kg/m³ density each board weighs approximately 1.35 kg — still light enough for single-handed positioning once packs are broken down at working height, though the 180 mm depth requires wider scaffold platforms for comfortable handling.

Same System, Longest Standard Plug

• Compatible With All Standard EWI Adhesives and Finishes: Bond this board using cement-based or polyurethane foam adhesives from the EPS adhesives and basecoats range, then complete with basecoat, mesh, and render following the same build-up sequence as thinner primary insulation thicknesses. The installation method is identical to the rest of the range — only the fixing plug length changes to accommodate the deeper board profile.

Technical Specifications

Physical Properties

Property	Value
Manufacturer	Genderka Sp. z o.o.
Product Range	EPS 031 Fasada Extra Plus
Thickness	180 mm
Board Dimensions	1000 mm × 500 mm
Coverage per Board	0.50 m²
Boards per Pack	3
Pack Coverage	1.5 m²
Density	15 kg/m³
Colour	Steel grey (graphite)
Compressive Strength (CS)	≥ 70 kPa
Bending Strength (BS)	≥ 100 kPa (BS100)
Tensile Strength (TR)	≥ 100 kPa (TR100)
Dimensional Stability — Normal	± 0.2 % (DS(N)2)
Dimensional Stability — 70 °C	≤ 2 % (DS(70,-)2)
Reaction to Fire	Class E (EN 13501-1)
Standard	EN 13163:2012+A1:2015

Thermal Performance

Property	Value
Declared Thermal Conductivity (λD)	0.031 W/mK
Thermal Resistance (RD) at 180 mm	5.80 m²K/W
Classification String	EPS EN 13163 T1-L2-W2-Sb2-P5-BS100-DS(N)2-DS(70,-)2-TR100

Best Use Scenarios

Ideal Applications

• Passive House New-Build and Pre-Certification: The primary use case for this thickness. Projects pursuing Passive House certification benefit from 180 mm of graphite EPS as the external wall insulation layer, delivering wall U-values of 0.15–0.17 W/m²K that satisfy or closely approach the ≤ 0.15 W/m²K fabric target within a Passive House energy-balance model.
• Energiesprong Whole-House Retrofit: UK Energiesprong programmes specifying factory-precision EWI panels benefit from the 180 mm board's substantial R-value, supporting the guaranteed-performance contracts that characterise this delivery model. The consistent λD 0.031 W/mK across the full production range underpins reliable U-value calculations at scale.
• Net-Zero Carbon New-Build: Developers and architects designing to net-zero operational carbon standards benefit from the compliance headroom that 180 mm provides, reducing the heating demand contribution from external walls to the lowest practical level before stepping up to the maximum 200 mm thickness in the range.
• Social Housing Decarbonisation Fund — Band A Pathway: Housing associations targeting EPC band A on coordinated whole-house upgrades benefit from the 180 mm specification, which delivers the wall-element thermal performance needed to support band A SAP ratings when combined with high-performance glazing, loft insulation, and mechanical ventilation with heat recovery.

When an Alternative Fits Better

• Deep Renovation Without Passive House Ambition: Where the specification targets enhanced Part L compliance or Future Homes Standard readiness rather than Passive House fabric targets, the 160 mm Grafit board at R 5.15 m²K/W delivers U-values of 0.17–0.19 W/m²K at a reduced material cost and marginally slimmer build-up.
• Maximum Insulation Depth in the Range: For projects where the energy-balance calculation demands every additional millimetre of thermal resistance, the 200 mm Grafit board at R 6.45 m²K/W provides the absolute maximum insulation depth available in the Genderka EPS 031 Fasada Extra Plus range, achieving wall U-values of approximately 0.13–0.15 W/m²K on standard masonry.
• High-Rise or Non-Combustible Requirements: Where Euroclass A1 fire rating is mandated, the mineral wool insulation range provides non-combustible slabs compliant with Building Safety Act façade requirements for buildings above 18 metres.

System Integration

The 180 mm graphite EPS board forms the thermal core of a high-performance EWI build-up on Passive House, Energiesprong, and net-zero projects. Apply adhesive from the adhesives and basecoats collection to the back face using the circumferential-and-spot method — aim for a minimum 40 % contact area between the adhesive and the substrate to satisfy wind-load design requirements under BS EN 1991-1-4. At 180 mm board depth, adhesive consistency is critical: maintain a continuous perimeter bead at least 30 mm wide and three central spots each at least 100 mm in diameter to ensure full support across the board face, preventing deflection under negative wind pressure on exposed elevations.

After a minimum of 24 hours' adhesive curing, secure each board with 6–8 mechanical fixings per m² from the fixing accessories range. The matching plug for this thickness is the LTX 220 mm polystyrene fixing plug — the longest in the standard LTX range — which provides the correct embedment depth into standard masonry substrates for a 180 mm board with adhesive layer. Once fixed, rasp or sand the outer face to create an adhesion key, then apply the reinforcing basecoat with embedded Atlas 150 g/m² fibreglass mesh for long-term crack resistance. The complete layer-by-layer build-up sequence — from substrate preparation through to the decorative render finish — is detailed in the EWI system build-up layers guide.

Comparison Table — Genderka EPS Grafit Range

Property	160 mm Grafit	180 mm Grafit (This Board)	200 mm Grafit
Thickness	160 mm	180 mm	200 mm
λD	0.031 W/mK	0.031 W/mK	0.031 W/mK
RD	5.15 m²K/W	5.80 m²K/W	6.45 m²K/W
Approx. Wall U-Value (215 mm solid brick)	0.17–0.19 W/m²K	0.15–0.17 W/m²K	0.13–0.15 W/m²K
Pack Coverage	1.5 m²	1.5 m²	1.5 m²
Boards per Pack	3	3	3
Typical Use	Deep renovation	Part L compliance / near-Passive	Passive House / near-zero maximum

UK Climate Performance Context

On a typical UK property with 215 mm solid brick walls (original U-value around 2.1 W/m²K), adding 180 mm of graphite EPS with λ 0.031 W/mK reduces the wall U-value to approximately 0.15–0.17 W/m²K — a reduction of over 92 % in heat flow through the wall and a result that places the wall element firmly within the range required by Passive House and near-zero energy design methodologies. For a three-bedroom semi-detached home with roughly 80 m² of exposed wall area, this translates to an estimated annual heating energy saving of 7,500–9,000 kWh compared with the un-insulated baseline, depending on heating system efficiency and exposure zone. In SAP calculations, this level of wall insulation can shift a property from EPC band D or E into band A or upper B when combined with comprehensive loft, floor, and glazing upgrades. On lower-conductivity brickwork (≤ 0.70 W/mK), the assembly approaches the 0.15 W/m²K threshold that Passive House projects target for external walls, meaning the 180 mm board can serve as the sole wall-insulation layer within a certified Passive House energy model without supplementary internal insulation.

Trade Insight: Handling and Storage

At 180 mm the boards are among the thickest in the Genderka range, and their physical bulk requires a few adjustments to standard EWI workflow. Store packs flat on a level surface under opaque sheeting — the steel-grey graphite surface absorbs solar radiation quickly, and at this thickness the thermal mass means the outer face can reach high temperatures in direct sunlight, softening the bead structure and weakening the adhesion key. When cutting boards to size, a long-blade hot-wire cutter gives the cleanest and fastest results; a fine-tooth handsaw works but requires a steady draw to maintain a straight cut face through the full 180 mm depth. For best adhesive bond, rasp the bonding face lightly before application and apply adhesive immediately after rasping — the fresh surface provides the strongest mechanical key, and at this board depth a reliable adhesive bond is especially important because the longer fixing shanks transmit more lever-arm force during wind events. One practical consideration for scaffold setup: standard 600 mm scaffold boards leave limited working space once a 180 mm board is propped against the wall, so widening the working platform to 900 mm or using a double-board configuration provides the room needed for comfortable adhesive application and fixing operations. Pre-staging packs on each lift in fixing sequence before the adhesive operation begins keeps the workflow efficient and the platform clear.

Certifications and Compliance

• EN 13163:2012+A1:2015: Harmonised European standard for factory-made expanded polystyrene products used in buildings, covering declared thermal conductivity, dimensional tolerances, and mechanical strength properties.
• Reaction to Fire — Euroclass E: Suitable for use within EWI systems on buildings up to 18 m in height when combined with approved fire-barrier detailing at each floor level, in accordance with Approved Document B and Building Safety Act guidance.
• CE Marking and DoP: Each production batch carries a Declaration of Performance referencing the specific Genderka factory of origin (Bydgoszcz, Ostrów Mazowiecka, Oświęcim, Brzeziny, or Wschowa), supporting full traceability for Building Control inspections.
• Part L, Future Homes, and Passive House Contribution: At R 5.80 m²K/W, the 180 mm board forms part of a wall assembly that substantially exceeds Approved Document L targets (0.30 W/m²K retrofit, 0.26 W/m²K new-build), aligns with the enhanced fabric expectations of the Future Homes Standard, and approaches the ≤ 0.15 W/m²K wall U-value target used in Passive House energy-balance calculations.

Technical Disclaimer

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. Always verify system-level U-value calculations with a competent energy assessor or building control body before specifying. Specifications are subject to manufacturer update; confirm current data at point of order.

Summary

The Genderka EPS Grafit 180 mm board delivers λ 0.031 W/mK and R 5.80 m²K/W — a near-Passive-House thickness that brings typical UK masonry walls to approximately 0.15–0.17 W/m²K, substantially exceeding all current Approved Document L targets and approaching the ≤ 0.15 W/m²K wall fabric threshold for Passive House certification. Each pack of 3 boards covers 1.5 m², sized for efficient ordering on high-performance new-build, Energiesprong, and net-zero retrofit programmes. Where deep renovation without Passive House ambition is the target, the 160 mm Grafit board delivers R 5.15 m²K/W within a marginally slimmer profile. For the absolute maximum insulation depth in the range, the 200 mm Grafit board steps up to R 6.45 m²K/W — achieving wall U-values of 0.13–0.15 W/m²K on standard masonry constructions.

Frequently Asked Questions

How many 180 mm boards are in a pack, and how many packs do I need for a typical Passive House or deep-renovation project?

Each pack contains 3 boards covering 1.5 m². A three-bedroom detached new-build with approximately 100–120 m² of external wall area (after deducting windows and doors) requires roughly 70–85 packs, including 5–10 % for cutting waste around reveals, soffits, and service penetrations. For semi-detached properties with smaller exposed wall areas, order quantities scale proportionally against the measured survey — early engagement with the Renders World team helps coordinate phased delivery for projects with limited on-site storage.

What is the environmental benefit of specifying 180 mm of graphite EPS on a net-zero or Passive House project?

Graphite EPS is fully recyclable through specialist polystyrene recovery programmes, and off-cuts generated on site can be returned for granulation and re-expansion into new products. The primary environmental benefit is operational: achieving a wall U-value of 0.15–0.17 W/m²K cuts annual heating energy demand by an estimated 7,500–9,000 kWh on a typical property compared with the un-insulated baseline. Over a 30-year design life, this translates to a substantial cumulative CO₂ reduction, with the embodied energy of manufacture typically paid back within the first heating season at this insulation depth.

Does the 180 mm board achieve Passive House wall U-value targets on standard masonry?

On a typical 215 mm solid brick wall, 180 mm of graphite EPS brings the assembly U-value to approximately 0.15–0.17 W/m²K. The Passive House Institute's general target for external walls is ≤ 0.15 W/m²K. On well-pointed brickwork with lower conductivity (≤ 0.70 W/mK), the 180 mm board can reach this threshold on the wall element alone. On higher-conductivity brickwork, the assembly sits marginally above 0.15 W/m²K — which Passive House energy-balance modelling typically accommodates when compensated by high-performance glazing, airtightness, and mechanical ventilation with heat recovery. For projects requiring a definitive independent wall-element pass at ≤ 0.15 W/m²K regardless of brick type, the 200 mm board provides the additional margin.

What fixing plug length pairs with the 180 mm board on standard masonry?

The LTX 220 mm polystyrene fixing plug — the longest in the standard LTX range — is the correct match for a 180 mm board on standard masonry substrates, providing approximately 30–40 mm of embedment beyond the board thickness and adhesive layer. This plug is supplied in packs of 100 pieces (rather than the 200-piece packs used for shorter plugs), so factor the different pack quantity into your ordering calculations. Install 6–8 fixings per m² in the pattern recommended for the project's wind-load zone, and use a depth stop on the drill to ensure consistent embedment across the full elevation.