Description
For UK projects where lintel and soffit junctions need close to a full unit of R-value in a compact profile, EPS Grafit 30 mm delivers λD 0.031 W/mK and R 0.95 m²K/W as the cost-effective entry thickness in the Genderka EPS 031 Fasada Extra Plus range, supplied at 20 boards per pack covering 10 m² for domestic detailing and composite build-up work.
What EPS Grafit 30 mm Does in a UK EWI System
EPS Grafit 30 mm is a graphite-enhanced polystyrene board certified to EN 13163, delivering λD 0.031 W/mK and R 0.95 m²K/W in a 1000 × 500 mm panel that sits at the boundary between detailing-grade and primary insulation performance within a UK external wall insulation build-up. The board's natural home is the lintel, ring-beam, and soffit return — locations where the 20 mm board undershoots the psi-value target and a 50 mm primary thickness either eats too much depth or imposes excess weight on a horizontal joint. It belongs to the wider graphite EPS insulation range, which covers every façade zone from reveal strips through to Passive House main-wall thicknesses.
At nearly a full unit of R-value in a 30 mm profile, this board moves the conversation past pure thermal-bridge closure and into measurable SAP-calculation gain. Wrap concrete lintels with 30 mm of graphite EPS and the localised heat loss at those elements falls by roughly 55 to 60 percent — enough to register as a two-to-four point SAP improvement across a typical three-bedroom semi-detached retrofit.
Why Specifiers Choose EPS Grafit 30 mm for UK Junctions
- R 0.95 m²K/W in a 30 mm profile: close to a full unit of thermal resistance in a compact thickness, putting concrete lintel and ring-beam junctions firmly below the default psi-values published in BR 443 for SAP and PHPP fabric calculations.
- Twenty boards per pack, 10 m² of detailing coverage: one pack covers lintel and soffit work across a typical three-bedroom semi-detached façade with margin for cutting waste around complex profiles.
- Cost-effective entry thickness for standalone duty: 30 mm is the first variant in the range where the R-value supports genuine standalone insulation contribution rather than pure bridge closure — meaningful EPC progress per pound of material.
- Composite build-up precision: laminate 30 mm onto an 80 mm primary board for 110 mm total depth, or onto 100 mm for 130 mm, giving fine-tuned U-value control without specifying a non-standard slab.
- Identical mechanical spec across the range: CS70, BS100, and TR100 carry over from every Grafit thickness, so the adhesive bed pattern and fixing schedule used on the main wall transfer directly to the junction layer.
- UK warehouse stock for next-working-day dispatch: the junction thickness ships in the same consignment as the main-wall pallets, so detailing material arrives with the rest of the EWI order rather than as a separate back-order.
- Full DoP traceability for compliance audits: each batch carries a factory-specific Declaration of Performance referencing Bydgoszcz, Ostrów Mazowiecka, Oświęcim, Brzeziny, or Wschowa — supporting Building Control sign-off and PAS 2035 retrofit audits.
Thermal Specifications — λ, R-Value, Reaction to Fire
| Property | Value |
|---|---|
| Declared Thermal Conductivity (λD) | 0.031 W/mK |
| Thermal Resistance (RD) at 30 mm | 0.95 m²K/W |
| Reaction to Fire (EN 13501-1) | Euroclass E |
| Classification String (EN 13163) | T1-L2-W2-Sb2-P5-BS100-DS(N)2-DS(70,-)2-TR100 |
| Equivalent White EPS Thickness | ≈ 37 mm at λ 0.038 W/mK |
R 0.95 m²K/W sits at the practical threshold where junction insulation begins to contribute as a near-unit thermal-resistance layer rather than purely a bridge-closure detail. The board's contribution flows through the linear thermal transmittance (psi-value) at wall-to-opening and wall-to-roof junctions, and most concrete lintels treated at this thickness fall below the default psi-values published in BR 443 — the figures SAP assessors fall back on when no calculated value is supplied. The U-value calculation guide for wall insulation thickness covers how junction insulation feeds into the dwelling fabric calculation.
Physical Specifications — Density, Mechanical Strength, Dimensions
| Property | Value |
|---|---|
| Manufacturer | Genderka Sp. z o.o. |
| Product Range | EPS 031 Fasada Extra Plus |
| Thickness | 30 mm |
| Board Dimensions | 1000 × 500 mm |
| Coverage per Board | 0.50 m² |
| Boards per Pack | 20 |
| Pack Coverage | 10.0 m² |
| Density | 15 kg/m³ |
| 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) |
| Colour | Steel grey (graphite) |
| Standard | EN 13163:2012+A1:2015 |
Where EPS Grafit 30 mm Performs Best — Lintels, Soffits, Composite Layers
The 30 mm board earns its place in four specific zones of a UK EWI build-up, each characterised by the gap between detailing thicknesses and main-wall slabs. Concrete lintel returns top the list: exposed lintels behave as thermal short-circuits with localised U-values around 3.5 W/m²K before treatment, and 30 mm of graphite EPS drops that localised value by more than half. The resulting psi-value at the head-of-window junction typically falls below the BR 443 default, removing the SAP penalty that uninsulated lintels otherwise impose on the dwelling rating.
Composite build-ups follow as the second high-value use case. Laminate 30 mm onto an 80 mm primary board and the assembly reaches 110 mm total depth — the exact thickness that brings many solid-wall constructions into Approved Document L retrofit targets without specifying a non-standard slab. The technique is particularly useful at parapets and column edges where total depth needs precise control.
- Lintel and ring-beam insulation: wrapping exposed concrete structural elements with sufficient R-value to bring the junction psi-value below BR 443 defaults.
- Soffit primary layer: single-layer insulation beneath concrete or timber soffits where depth is constrained but a meaningful R-value is required.
- Secondary equalising layer: bonded over an uneven render carrier or existing rough masonry to deliver a flat, thermally enhanced surface for the primary insulation course or directly for basecoat and mesh.
- Composite thickness build-up: laminated onto thicker primary boards (80 mm + 30 mm = 110 mm; 100 mm + 30 mm = 130 mm) for non-standard depth targets and fine-tuned U-value compliance.
How EPS Grafit 30 mm Fits Into a Full EWI System
Within the layered build-up, the 30 mm board installs either as a standalone junction layer at lintels and soffits or laminated onto a thicker primary board for a composite assembly. Apply adhesive from the EPS adhesives and basecoats range full-bed to the back face — perimeter-and-dab gives unreliable bond at this profile and leaves voids that telegraph through the basecoat. Press firmly onto the prepared lintel, soffit, or substrate surface with tight butt joints, leaving no gaps wider than 2 mm between adjacent boards. On horizontal soffit work, temporary propping until adhesive cure (typically 24 hours) keeps the board firmly against the substrate.
Once bonded and (where specified) fixed with a short plug from the fixing accessories range, the basecoat reinforcement layer wraps continuously from the main wall face around any junction returns with embedded alkali-resistant fibreglass mesh, creating a monolithic crack-resistant surface across the entire assembly. The full layer-by-layer sequence is covered in the complete EWI system build-up and layers explained guide. For the fixing pattern that secures main-wall boards above and below the 30 mm junction layer, the insulation board fixing pattern and spacing guide sets the densities most UK installers work to.
How EPS Grafit 30 mm Compares to Sibling Thicknesses
| Property | 20 mm Grafit | 30 mm (this board) | 50 mm Grafit |
|---|---|---|---|
| Thickness | 20 mm | 30 mm | 50 mm |
| λD | 0.031 W/mK | 0.031 W/mK | 0.031 W/mK |
| RD | 0.60 m²K/W | 0.95 m²K/W | 1.60 m²K/W |
| Boards per Pack | 30 | 20 | 12 |
| Pack Coverage | 15.0 m² | 10.0 m² | 6.0 m² |
| Typical Use | Soffits, lintels, secondary layer | Cost-effective entry thickness, composite layer | Primary insulation, depth-constrained walls |
The three thicknesses bracket the transition from detailing-grade to primary insulation. The 20 mm board sits clearly in junction territory; the 50 mm board is the first variant designed to carry standalone main-wall duty on depth-constrained elevations. The 30 mm board occupies the boundary between them — heavy enough to make a measurable SAP contribution on lintels and soffits, light enough to laminate cleanly onto thicker primary boards for non-standard total depths.
How EPS Grafit 30 mm Performs in UK Weather — Moisture, Frost, Wind
The board's W2 water absorption classification and DS(70,-)2 dimensional stability mean it holds declared performance through UK seasonal cycling, where wind-driven rain and freeze-thaw stress concentrate at lintel and soffit edges. The closed-cell graphite EPS matrix absorbs negligible bulk moisture, and the BS100 bending strength accommodates thermal movement between summer surface temperatures and winter night-time lows without cracking at the joint between this layer and the surrounding main-wall boards.
One handling note matters specifically at 30 mm thickness. The board is the first in the slim band that holds its shape firmly in a stack without flex, so storage is straightforward — packs sit flat without distortion and lift cleanly off the pallet. The steel-grey graphite finish, however, still absorbs solar radiation faster than white EPS, so keep packs under opaque sheeting until needed and fix boards to the wall the same working day they are unwrapped, protecting the bead-layer adhesion key against cumulative UV softening.
Pro Tips From UK Installers Using EPS Grafit 30 mm
Five habits separate a tight, callback-free junction install from one that needs returning visits at the soffit corner. None of them appear on the technical data sheet, and all of them come from the way experienced UK applicators sequence the work on multi-property programmes.
- Dry-fit composite layers before adhesive: when laminating 30 mm onto a thicker primary board, cut the 30 mm first and check the combined depth against the target at every opening before mixing adhesive. Small adjustments at this stage prevent rework once the bond is set.
- Single-pass long-blade Stanley knife: a sharp blade taken cleanly through in one stroke gives a square cut edge that maximises adhesive contact at the next butt joint. Score-and-snap leaves a ragged surface that reduces effective bond area at this thickness.
- Pre-cut and label by opening: measure all lintel and soffit zones during the pre-scaffold survey, cut the full 30 mm allocation at ground level, and label each piece by elevation and opening number. On-scaffold productivity rises sharply when no cutting happens at height.
- Full-bed adhesive, never perimeter-and-dab: at 30 mm the partial-contact pattern leaves voids that compromise long-term adhesion and telegraph through the basecoat. Butter the entire back face for reliable contact across the full board area.
- Wrap mesh continuously across the junction: embed the same fibreglass mesh used on the main wall around any soffit or lintel return without breaking the lap — this is the detail that prevents micro-cracking at the corner where the two planes meet.
Handling and Storage on Site
Stack packs flat on a level surface — at 30 mm the boards hold their shape in a stack, so distortion is not a concern, but lifting packs by the strapping rather than the short ends still gives the cleanest delivery from pallet to platform. Keep packs under opaque sheeting until needed, both to prevent UV softening of the graphite surface and to keep boards at ambient temperature for predictable adhesive open-time. A long-blade Stanley knife produces the cleanest through-cut in a single confident pass at this thickness; a hot-wire cutter works for repetitive composite-layer strips when fed at a steady rate.
Certifications and Compliance — EN 13163, Euroclass E
- EN 13163:2012+A1:2015: the harmonised European standard for factory-made expanded polystyrene in buildings, covering declared thermal conductivity, dimensional tolerances, mechanical strength, and water absorption.
- Reaction to Fire — Euroclass E: typically suitable for use within EWI systems on residential buildings below 18 metres, where the project fire strategy permits Euroclass E with approved fire-barrier detailing under current Approved Document B guidance.
- CE Marking and Declaration of Performance: each production batch carries a DoP referencing the specific Genderka factory of origin (Bydgoszcz, Ostrów Mazowiecka, Oświęcim, Brzeziny, or Wschowa), supporting full traceability for Building Control inspections and PAS 2035 retrofit audits.
- Junction Detailing Under Part L: insulating lintels and soffits with graphite EPS supports the linear thermal transmittance (psi-value) calculation at critical junctions under current Approved Document L guidance and the conventions set out in BR 443.
Is EPS Grafit 30 mm Right for Your Project?
- Specify EPS Grafit 30 mm for lintel, ring-beam, and soffit primary layers on EWI build-ups where the junction needs close to a full unit of R-value but main-wall thicknesses cannot fit without compromising visible head detail or opening proportions.
- Use as a composite top-up layer on top of thicker primary boards to reach non-standard total depths (80 mm + 30 mm = 110 mm; 100 mm + 30 mm = 130 mm) for fine-tuned U-value compliance on retrofit work.
- Drop to the 20 mm Grafit board for soffit and lintel work where 20 mm is the deepest profile that fits the available junction geometry without encroaching on the glazing line.
- Step up to the 50 mm Grafit board when the junction or main-wall depth allows true primary-layer thickness on depth-constrained elevations such as parapets and side returns.
- Switch to mineral wool slabs where the project fire strategy requires non-combustible A1-rated insulation across the whole build-up, typically on residential buildings above 18 metres.
- Confirm thickness against the dwelling target using the Future Homes Standard 2026 insulation requirements guide for new-build work and Approved Document L for retrofit programmes.
Declared thermal values (λD, RD) are stated per EN 13163 and the Genderka manufacturer technical data sheet. Actual installed performance depends on substrate condition, adhesive coverage, and the complete EWI system build-up. Verify current data with the manufacturer or the project energy assessor before specification.
What to Order Next — Pack Sizes, Lead Times, Compatible Components
One pack of 20 boards covers 10 m² of junction and composite-layer detailing — typically enough for all lintel and soffit zones on a three-bedroom semi-detached retrofit with 5 to 10 % cutting margin. Pair the order with the matching adhesive from the EPS adhesives and basecoats range and the appropriate short fixing plug from the fixing accessories range if the specification calls for mechanical retention at exposed soffits or composite assemblies. UK warehouse stock supports next-working-day dispatch on full-pack quantities ordered before midday, so the junction material arrives with the rest of the EWI consignment rather than as a separate delivery.
FAQ — EPS Grafit 30 mm Coverage, Compatibility, Installation
How many 30 mm boards are in a pack, and what area does one pack cover?
Each pack contains 20 boards, each measuring 1000 × 500 mm, giving a total pack coverage of 10.0 m². For lintel and soffit detailing on a three-bedroom semi-detached retrofit, one pack generally covers all junction zones with a 5 to 10 % allowance for cutting waste around complex profiles, services, and non-standard opening sizes.
Can the 30 mm board be combined with thicker boards for a custom total depth?
Composite build-ups are an accepted EWI detailing technique and the 30 mm board is the natural top-up thickness for this approach. Bond the 30 mm board to the face of the thicker primary board using a thin bed of compatible adhesive, then apply the reinforcing basecoat and mesh across the entire composite surface as a single continuous layer. Combinations such as 80 mm + 30 mm = 110 mm or 100 mm + 30 mm = 130 mm give precise U-value control without specifying a non-standard slab.
Does a 30 mm board require mechanical fixings, or is adhesive enough?
For most lintel and soffit applications, a full-bed adhesive bond with temporary propping until cure (typically 24 hours) is sufficient — at approximately 0.225 kg per board, gravity load on a horizontal adhesive joint is minimal. Where the project specification or Building Control requires mechanical retention at exposed soffits or composite assemblies, a short fixing plug installed after adhesive cure handles the duty, provided the substrate behind the board offers at least 25 mm embedment depth into sound masonry or concrete.
Can the 30 mm board be used as primary wall insulation?
At R 0.95 m²K/W, the 30 mm board is best suited to junction detailing and secondary or composite layers rather than standalone main-wall insulation. Approved Document L wall U-value targets (0.26 W/m²K for new build, around 0.30 W/m²K for retrofit where feasible) require substantially thicker insulation across the main wall area — typically 80 mm to 160 mm of graphite EPS depending on the existing construction. The 30 mm board reaches its full value as a junction layer or composite top-up to those main-wall thicknesses.
How does the 30 mm compare to the 20 mm and 50 mm Grafit variants?
All three share λD 0.031 W/mK and identical mechanical properties (CS70, BS100, TR100). The difference is R-value and the application band: the 20 mm variant gives R 0.60 m²K/W at 30 boards per pack for tighter soffit and lintel work, 30 mm gives R 0.95 m²K/W at 20 boards per pack as the cost-effective entry thickness for standalone junction duty or composite top-ups, and the 50 mm variant reaches R 1.60 m²K/W at 12 boards per pack as the first true primary-insulation thickness for depth-constrained elevations.
How much SAP improvement does insulating lintels and soffits at 30 mm deliver?
Fully insulating lintels and soffits at 30 mm on a typical three-bedroom semi-detached property can improve the energy performance certificate by approximately 2 to 4 SAP points, subject to project-specific calculation by the SAP assessor. The improvement comes from reducing the linear thermal transmittance (psi-value) at wall-to-opening and wall-to-roof junctions below the BR 443 defaults — a meaningful step that often makes the difference between adjacent EPC bands on properties close to the boundary.
What fire classification rules apply when specifying 30 mm graphite EPS in the UK?
The board carries a Euroclass E reaction-to-fire classification under EN 13501-1 and is typically suitable for residential buildings below 18 metres, where the project fire strategy permits Euroclass E with approved fire-barrier detailing in accordance with current Approved Document B guidance. For taller buildings or higher-risk façades where the fire strategy requires non-combustible A1-rated insulation, mineral wool replaces EPS across the build-up. Confirm classification with the designer and Building Control at design stage to avoid substitutions on site.
Technical Documentation — EPS Grafit 30 mm TDS, DoP, Certificates