Description
This 100mm EPS insulation is a grey graphite polystyrene board, 1000 × 500 mm, for insulating external walls that are finished with render. A 100 mm board goes on the open face of the wall, with thinner boards from the same range in the reveals. It belongs to the Renders World graphite board range of eleven thicknesses.
Two boards cover a square metre; the declared thermal conductivity is ≤ 0.031 W/mK.
100mm EPS Insulation: What You Get
Each sheet of 100mm EPS insulation is 1000 mm long, 500 mm wide and 100 mm thick, giving 0.5 m² of cover. Graphite added during manufacture turns the polystyrene grey and improves how well it insulates, so a set thermal resistance is reached with less material.
| Property | Declared value |
|---|---|
| Thermal conductivity λD | ≤ 0.031 W/mK |
| Reaction to fire | Class E |
| Thickness tolerance | T1 (± 1 mm) |
| Length and width tolerance | L2, W2 (± 2 mm) |
| Squareness | S5 (± 5 mm per 1000 mm) |
| Flatness | P5 (5 mm) |
| Bending strength | BS100 (≥ 100 kPa) |
| Tensile strength perpendicular to the faces | TR100 (≥ 100 kPa) |
| Dimensional stability, normal conditions | DS(N)2 (≤ 0.2 %) |
| Dimensional stability, set temperature and humidity | DS(70,-)2 (≤ 2 %) |
Fire class E belongs to the insulation alone. Once rendered, the wall is classified as a whole system, and that classification comes from the system specification. The U-value and insulation thickness guide shows how 100 mm turns into a U-value for a particular wall.
100 Is the Thickness, Not a Grade
A lot of 100 mm polystyrene on sale in the UK is floor insulation in 2400 × 1200 mm sheets, sold by grade as EPS 70 or EPS 100. Here the 100 is the thickness in millimetres:
- this 100mm EPS insulation is a façade board for walls;
- it does not go under a screed, under paving or into the ground.
For foundation walls, plinths and other work below ground or in lasting damp, Renders World sells a separate 100 mm foundation board made for those conditions.
Why Choose a 100mm Graphite Board
- A full wall thickness. At 100 mm it is insulation for the open façade, not only for reveals and tight spots.
- Graphite performance. ≤ 0.031 W/mK means more insulation from every millimetre of the build-up.
- Square, flat and true. ± 1 mm on thickness, ± 2 mm on length and width and 5 mm flatness keep joints tight and the mesh layer even.
- Strong enough for render. The EPS bending and tensile strength are each at least 100 kPa.
- Stable. Under normal conditions the board moves no more than 0.2 %.
- One system, many depths. The same 1000 × 500 mm format runs from 20 mm to 200 mm, so thicker and thinner boards meet cleanly at openings.
- Two adhesive options. Cement-based or polyurethane.
Where a 100mm Board Goes
- Rendered external walls, bonded and rendered, or fixed by the light-dry method.
- Loggias and balconies with enough depth for 100 mm.
- Stud walls, on the outside face.
- Cavity walls, in the enclosed or the ventilated slot.
Concrete, cement and cement-lime plaster, bare brick, block and hollow block in ceramic or silicate, and aerated concrete all take the adhesive.
How Many Boards of 100mm EPS Insulation to Order
Order this thickness by the board: two to each square metre of 100mm EPS insulation.
- A 30 m² gable takes 30 ÷ 0.5 = 60 sheets of 100 mm EPS.
- Openings come out of the wall area, but the reveals need their own thinner boards, so list that EPS as a second item.
- Offcuts from the 100 mm boards rarely suit a reveal, so plan reveal lining in 20 or 30 mm from the start.
Fitting the Board
Use a cement-based or polyurethane adhesive from the adhesives and basecoats for insulation boards. The wall has to be frost-free, stable, even and sound, with dust, dirt, lime, oil, grease, wax and old emulsion or oil paint cleaned off.
- Prime and fill. Absorbent backgrounds, weak cement or cement-lime render and rough aerated or cinder block are primed with Uni-Grunt priming emulsion. Deep hollows and gaps are made good first with ZW 330 mortar or Plastering Mix M, which appears in the shop as One Coat Dash Cover.
- Spread the adhesive. A continuous edge strip at least 3 cm wide, plus 6 to 8 dabs 8 to 12 cm across. At least 40 % of the EPS is covered, 60 % after pressing.
- Press and level. Fix the EPS immediately with no more than 10 mm of adhesive behind it. On a smooth, even wall a notched trowel can spread adhesive over the whole EPS face instead, ending as a 2 to 5 mm layer.
- Sand and dust. The surface must be frost-free, even, clean and stable before the base coat; sanding and dusting graphite EPS first is advised.
Fixings and the mesh-reinforced layer follow: see the insulation fixing accessories, the board fixing pattern and spacing guide and the EWI build-up and layers guide.
Keep Graphite Boards Out of the Sun
On a sunny site, 100mm EPS insulation needs three precautions:
- No warm EPS on the wall. Protect the insulation from heating while it is fixed and while the adhesive first sets, or the bond can let go.
- Shaded storage. Keep the packs closed and away from direct sunlight, which can distort them.
- Weather cover. Hang scaffold covers and pause in snow, rain or strong wind.
Faces left exposed for long periods, particularly to UV, can turn yellowish; sand that off before the base coat. Acetone, nitro thinners, benzene and similar solvents attack polystyrene, so keep them well away.
Where the wall's strength is in doubt, bond 8 to 10 polystyrene cubes of 10 × 10 cm at several points and pull them after 3 days. A clean break inside the cube passes; a cube that lifts adhesive or part of the wall fails, and the insulation design has to cover the remedy.
100mm Among the Other Thicknesses
From 20 mm up every thickness shares the 1000 × 500 mm board, so different depths can sit on one elevation:
| Thickness | Sheets per m² | Full pack |
|---|---|---|
| 10 mm | 2 | order by the sheet |
| 20 mm | 2 | 30 sheets, 15.00 m² |
| 30 mm | 2 | 20 sheets, 10.00 m² |
| 50 mm | 2 | 12 sheets, 6.00 m² |
| 80 mm | 2 | 7 sheets, 3.50 m² |
| 90 mm | 2 | 6 sheets, 3.00 m² |
| 100 mm (this board) | 2 | order by the sheet |
| 150 mm | 2 | 4 sheets, 2.00 m² |
| 160 mm | 2 | 3 sheets, 1.50 m² |
| 180 mm | 2 | 3 sheets, 1.50 m² |
| 200 mm | 2 | 3 sheets, 1.50 m² |
Which thickness of insulation your wall needs is a U-value calculation for the whole build-up.
Ordering, Delivery and Returns
Renders World processes orders the same day when the stock is there.
- Delivery: quoted by the team after the order; parcels up to 25 kg go next day, pallets next day or in two business days on the economy option, always kerbside.
- Collection: from the counter at Unit 9A, Central Trading Estate, Southampton SO14 5JP, Monday to Friday 7am to 5pm and Saturday 7am to 12pm.
- Returns: goods bought directly from Renders World can go back within 14 days in their original condition; special orders and promotion purchases are excluded.
FAQ
What size is one board?
1000 × 500 × 100 mm, which covers 0.5 m². Two boards make one square metre.
How do I order it?
By the board, two boards per square metre of wall, plus thinner boards for the reveals.
Is this an EPS 100 floor board?
No. The 100 is the thickness. This is a wall board; floors need a board made for floor loads, and foundations and plinths take the 100 mm foundation board.
What is its thermal conductivity?
λD ≤ 0.031 W/mK. The U-value depends on the whole wall, so it comes from a build-up calculation.
Which adhesive should I use?
A cement-based or polyurethane adhesive, applied as an edge strip with dabs so that at least 40 % of the board is covered and no more than 10 mm sits behind it.
What goes in the window reveals?
A thinner board from the same range, such as the 20 mm sheet, so the insulation continues into the opening.
Do the boards need protecting on site?
Yes. Keep them wrapped and shaded, fix them cool, and work behind scaffold covers.
Technical Documentation