Description
Polystyrene EPS Grafit 50mm is the graphite-enhanced polystyrene board Renders World stocks for reveals, soffits, parapet returns and elevations where build-up depth is tight, and it sits between the detailing thicknesses and the main-wall boards on the graphite EPS insulation boards shelf.
Where the 50 mm Graphite EPS Board Fits on a UK Wall
Polystyrene EPS Grafit 50mm carries a declared thermal conductivity of 0.032 W/mK and a declared thermal resistance of 1.55 m²K/W, which suits reveals, soffits, parapet returns and elevations where build-up depth is restricted. Both figures are declared for GENDERKA EPS 032 FASADA EXTRA under EN 13163:2012+A1:2015, and the resistance is the declared table value for the 50 mm row rather than thickness divided by conductivity.
A conductivity of 0.032 W/mK sits at the graphite end of expanded polystyrene, so 50 mm reaches a resistance that a white board needs a deeper section to match. That is what makes this thickness useful on the details where a boundary line, a window reveal or an existing feature fixes the depth before the thermal target does.
- Reveals, soffits and junction returns where a thicker board would foul the frame or the drip edge.
- Parapet and roof-edge returns carried over from the main wall so the insulation runs continuously round the detail.
- Depth-restricted elevations and secondary overlays where the projection is capped and every millimetre of section has to work.
Declared Performance: Conductivity, Resistance, Strength and Fire
Every figure below is declared for GENDERKA EPS 032 FASADA EXTRA, technical card W32FE, in its technical data sheet and in its Bydgoszcz Declaration of Performance, at board level and under EN 13163:2012+A1:2015.
| Declared property | Value |
|---|---|
| Thermal conductivity λD | 0.032 W/mK |
| Thermal resistance RD at 50 mm | 1.55 m²K/W |
| Reaction to fire | Class E |
| Bending strength | ≥ 75 kPa |
| Tensile strength perpendicular to faces | ≥ 80 kPa |
| Compressive strength at 10% deformation | Not declared |
| Thickness tolerance | ± 1 mm |
| Length and width tolerance | ± 2 mm |
| Squareness / flatness | ± 2 mm/m / ± 5 mm |
| Dimensional stability, normal conditions | ± 0.2% |
| Dimensional stability at 70 °C | ≤ 2% |
| Designation | T1-L2-W2-Sb2-P5-BS75-DS(N)2-DS(70,-)2-TR80 |
Two GENDERKA graphite grades stand behind this shelf and they do not declare the same numbers. The 032 grade above declares 0.032 W/mK with bending and tensile figures of 75 and 80 kPa, while the EPS 031 FASADA EXTRA PLUS Declaration of Performance from the Wschowa plant declares 0.031 W/mK, 100 kPa on both strengths and 1.60 m²K/W at 50 mm. The stricter set is published here, and the buying instruction that follows is a short one: confirm the grade and the supplying plant when the order is placed, and take the Declaration of Performance number from that plant's own document rather than from any page.
Compressive strength is the figure most often assumed rather than read. The Declaration of Performance carries no declared value for it, so this board is specified for facade insulation duty, and any load case such as backfill, paving or a trafficked plinth calls for a board declared for compression. Thermal resistance is likewise a board figure and not a wall U-value; the wall figure is produced by the build-up calculation set out in the U-value and insulation thickness calculation guide.
Reaction to fire class E is declared for the board itself. The performance of a finished rendered wall is a system property confirmed by the project fire strategy and the system holder, which keeps the board figure and the wall figure cleanly separated on the specification.
Why UK Specifiers Choose the 50 mm Graphite Board
- 1.55 m²K/W declared at 50 mm: a genuine step up from the detailing thicknesses while keeping the section shallow enough for reveals, returns and constrained elevations.
- ± 1 mm on thickness and ± 2 mm/m on squareness: tight tolerances mean butt joints close cleanly and the rasping pass ahead of the reinforced layer stays light rather than corrective.
- Class E declared at board level: the scope is unambiguous on paper, which is what a designer needs when the wall's own performance is being assessed as a system.
- Dimensional stability of ± 0.2% and ≤ 2% at 70 °C: a steel-grey board runs warm on a south elevation, and declared stability at 70 °C is the figure that speaks to that condition.
- Ordered by the single board: reveal and return quantities can be matched closely, so an awkward detail does not require a full pallet to be brought to site.
How to Install Polystyrene EPS Grafit 50mm — Bonding, Fixing, Reinforcement
Fitting Polystyrene EPS Grafit 50mm follows the manufacturer's sequence for grey boards, and the two instructions that matter most are the adhesive family and the wait before drilling.
- Sand the bonding face immediately before fixing. The data sheet recommends abrading the board surface to raise adhesion, and on graphite boards that pass is worth doing as the board goes up rather than in a batch beforehand.
- Bond with a permitted adhesive only: cement-based adhesives intended for grey graphite boards, polyurethane foams, or water-dispersion bituminous compounds, taken from the EPS adhesives basecoats range and used to its own data sheet.
- Keep solvents away from the board. No product containing organic solvents goes near expanded polystyrene, which rules out several general-purpose site sealants and cleaners.
- Wait at least 24 hours before mechanical fixing. Plugging is carried out no earlier than 24 hours after bonding; fixings come from the insulation fixing accessories range, and both the plug length and the pattern are set by the fixing manufacturer's table and the project wind-load calculation rather than by a rule of thumb — the fixing pattern and spacing guide explains how that layout is derived.
- Build the reinforced layer next. Once boards are bonded and plugged, the reinforced layer goes on with rendering mesh embedded in fresh basecoat, in the sequence described in the EWI system build-up and layers guide.
Storage, Solar Protection and Site Handling
Graphite boards need shading, and planning for it is straightforward once it is on the programme rather than discovered mid-fix.
- Shade the boards, absolutely: the steel-grey colour means the surface must be protected from direct sunlight, both brief and prolonged, during storage and while boards are being fixed — opaque sheeting on the stack and boards fixed off a shaded face are the practical version of that instruction.
- Keep packs dry: pallets leave shrink-wrapped but not weatherproof, so on-site cover is the customer's step and a worthwhile one before the first bonded course goes up.
- Store away from ignition sources, solvents and their vapours, and protect boards from mechanical damage in transit and on the stack.
- Work to the tolerance, not past it: with ± 5 mm flatness declared, a straightedge across the fixed face before rasping shows where the basecoat would otherwise carry the correction.
How the 50 mm Compares With the 30 mm and 80 mm Grafit Boards
| Board | Declared RD | Where it earns its place |
|---|---|---|
| EPS Grafit 30 mm | 0.90 m²K/W | Reveals, soffits and thin returns |
| EPS Grafit 50 mm (this board) | 1.55 m²K/W | Parapet returns and depth-restricted elevations |
| EPS Grafit 80 mm | 2.50 m²K/W | Main-wall area on domestic retrofit |
All three are declared from the same document at the same conductivity, so the choice is purely one of section and declared resistance: 0.90 to 1.55 to 2.50 m²K/W as the board deepens. The 50 mm reads as the detail-and-constraint thickness, and where nothing caps the depth, the deeper board does more for the same fixing labour.
Price, Pack Format and Delivery Terms
The listed price is £3.90 per board, August 2026, for the 1000 × 500 mm format shown on the product listing, with the board currently listed as available. One board covers 0.5 m², so £3.90 ÷ 0.5 m² = £7.80 per m² of wall at 50 mm before adhesive, fixings and the reinforced layer. Renders World does not display a VAT label on the price endpoint, so confirm the VAT position at checkout or with the sales desk.
- Board and pack: 1000 × 500 mm boards, listed at 12 boards and 6.0 m² per manufacturer pack.
- Processing: orders are processed the same day where stock is available, with restocking times advised where it is not.
- Carriage, site-wide: parcels up to 25 kg go next day; pallets up to 1200 kg go next day, or two business days on the economy option.
- Delivery is kerbside only, so arrange offloading and a dry, shaded store before the pallet arrives — insulation is bulky rather than heavy, and two people and a covered area handle it comfortably.
- Local delivery runs in the company van up to 15 miles from the Southampton headquarters, above the order value stated in the shipping policy.
Is the 50 mm Grafit Board Right for Your Project?
- Specify it where depth is capped — reveals, soffits, parapet returns and elevations held back by a boundary, a planning condition or an existing feature.
- Step up to the 80 mm Grafit board for main-wall area where nothing restricts the section, since 2.50 m²K/W comes off the same declared table for the same fixing sequence.
- Take the material question elsewhere first where the fire strategy drives the specification: the graphite EPS and mineral wool comparison sets out how the two are declared and assessed.
- Confirm the thickness against the target, not the board — for new-build work the Future Homes Standard guidance and the fabric calculation decide the section, and the declared resistance above is one input to it.
- Order the grade, the plant and the quantity together so the Declaration of Performance supplied with the delivery matches the boards on the wall.
FAQ — Ordering and Fitting the 50 mm Graphite EPS Board
How many boards do I need per square metre?
Each 1000 × 500 mm board covers 0.5 m², so 1 m² takes two boards and the listed 12-board pack covers 6.0 m². Add an allowance for cutting on reveals, returns and non-standard geometry, and order the reveal strips as a separate line so full boards are not cut down unnecessarily.
Which adhesives can be used with a graphite board?
Cement-based adhesives intended for grey graphite boards, polyurethane foam adhesives, and water-dispersion bituminous compounds are the three families named for this board. Anything containing organic solvents is excluded, and each adhesive's own coverage and open time govern on site.
What changes between the 30 mm, 50 mm and 80 mm boards?
Section and declared thermal resistance change: 0.90, 1.55 and 2.50 m²K/W respectively, from the same declared table at the same conductivity. Bonding, the 24-hour wait and the reinforced layer are identical, so the specification decision is about available depth.
Can these boards go below the damp-proof course or under paving?
Compressive strength is not declared for this board, so a plinth carrying backfill, paving or traffic loads is served by a board declared for compression and moisture exposure. Above ground, on a facade, this is exactly the duty the board is intended for.
Does class E mean the finished wall carries class E?
Class E belongs to the board as tested and declared. A rendered wall is assessed as a complete system, so the wall's fire performance comes from the system holder and the project fire strategy, and the board class is quoted as a board class on the specification.
Technical Documentation for This Board