EPS vs XPS: which polystyrene sheet to buy
Updated: 23 October 2026
You are about to buy the cheaper white sheet because the title says polystyrene, while someone has called blue or pink foam the proper stuff. EPS vs XPS is a difference you can see on a broken edge. It decides whether the board belongs in a dry lining, under a damp-proof membrane, or on a carving bench. This page is that fork. The listings are on the [polystyrene sheets comparison](/hub/diy-supplies/polystyrene-sheets). The Products Compared editorial team used public UK sources and those amazon.co.uk listings, on 22 October 2026. We did not compress a sample. A qualifying purchase can earn a commission at no extra cost to you.
You are about to buy the cheaper white sheet because the title says polystyrene, while someone has called blue or pink foam the proper stuff. EPS vs XPS is a difference you can see on a broken edge.
You are about to buy the cheaper white sheet because the title says polystyrene, while someone has called blue or pink foam the proper stuff. EPS vs XPS is a difference you can see on a broken edge. It decides whether the board belongs in a dry lining, under a damp-proof membrane, or on a carving bench. This page is that fork. The listings are on the polystyrene sheets comparison. The Products Compared editorial team used public UK sources and those amazon.co.uk listings, on 22 October 2026. We did not compress a sample. A qualifying purchase can earn a commission at no extra cost to you.
Our top picks
| Badge | Product | Material | Structure | Where it belongs | Note | Price | Offer |
|---|---|---|---|---|---|---|---|
| Best overall |  Triplast Triplast 12-pack EPS 70, 25 mm | EPS 70, white | Fused beads | Light, dry lining | 8.6 | about £47.79 | View offer |
| Best value |  Triplast Triplast 10-pack EPS 70, 10 mm | EPS 70, white | Fused beads | Thin dry lining | 8.6 | about £16.89 | View offer |
| Alternative |  SuQurtom SuQurtom 5-pack 20 mm boards | XPS claimed | Closed cell claimed | Small block, size conflict | 7.6 | about £12.59 | View offer |
On this page
Beads or a closed cell
Choose white bead EPS for a light, dry, low-load sheet. Choose a specified XPS board when the foam will sit in the wet, carry a floor, or hold a carved face. Colour is not the specification.
Expanded polystyrene is beads fused together. Snap a corner and you see the pearls. The British Plastics Federation describes EPS as mostly air, which is why a saw throws crumbs and water can track the bead boundaries. The three Triplast packs are EPS 70, white, listed as made in the United Kingdom.
Extruded polystyrene leaves a finer edge because the cells were formed in a die. It takes up less water, and a scribed line holds. Which? puts EPS on walls and roofs and XPS under slabs and in foundations. That is the usual split, not a ban on every EPS floor if a designer has specified the grade. Blue and pink were brand colours for XPS, not a strength class. A Triplast reviewer said the white sheets are not like dense blue or pink foam. Other families, including paper-faced board, are on the polystyrene sheets buying guide.
Load and water
EPS 70 means about 70 kPa at 10 per cent deformation under BS EN 13163. It is not a thickness. Stylite’s datasheet, as the meaning of the grade and not a test of Triplast, pairs it with 0.038 W/mK, about 15 kg/m³, and class F for standard EPS. Polyfoam says the 10 per cent figure is a reference, not the design load. The number on the datasheet is the grade.
Polyfoam cites typical XPS around 0.033–0.036 W/mK and EPS around 0.032–0.038 W/mK by grade. The Triplast bullet prints 0.038–0.030 on white sheet. Read the white end, about 0.038.
Water is the clearer split. Polyfoam’s reading of Approved Document C keeps insulation below a damp-proof membrane to boards with low water absorption, and places XPS there. EPS takes up more moisture, so it stays above the membrane. Ordinary EPS does not meet class A2-s1, d0 or A1 in regulation 7(2). If the job is a timber summerhouse, thickness and electrics are on the shed insulation page.
The EPS packs you can buy here
The three Triplast rows are white EPS 70. Twelve sheets at 1200 x 600 x 25 mm cover 8.64 m² at £47.79. Twenty-five sheets at 600 x 400 x 25 mm are £37.49. Ten sheets at 600 x 400 x 10 mm are £16.89. All three share 4.6 from 345 reviews, so the text is one pool. None prints a single lambda, a BBA number, or a U-value.
The five-pack that says XPS
The SuQurtom five-pack at £12.59 is the listing that says XPS. One bullet claims a closed-cell structure. The spec line says blue. There is no kPa grade and no density. The title says 30 x 20 x 2 cm, the spec line says 6 x 4 cm, and a reviewer measured about 28.9 x 20 x 2 cm. Three ratings sit at 4.4. That is a small block, not a floor board.
Nothing in this set is a certified XPS board for below a damp-proof membrane. Use EPS when you can see the beads, the sheet stays dry, and nobody is asking it to carry a slab. Use a specified XPS for the wet side of a membrane, a real floor load, or a carved edge that must not shed pearls. Leave the £12.59 pack out of both of those jobs.
Common questions
What is the difference on a broken edge?
EPS shows fused beads. XPS looks finer and more even, because it was extruded. The British Plastics Federation treats them as different processes. The edge plus the datasheet is the check. A blue skin on its own is not a grade.
Is EPS 70 strong enough for a house floor?
It is about 70 kPa at 10 per cent deformation, a domestic grade, and that figure is a reference rather than a design load. Heavier EPS grades exist, up to about 250 kPa when specified. A house floor needs the grade and the position written down. A Triplast pack does not become that specification because it says EPS 70.
Can white EPS go below a damp-proof membrane?
Polyfoam keeps insulation below the membrane to boards with low water absorption, and places XPS there. EPS takes up more moisture, so it stays above the membrane. Do not put these white packs under a DPM in wet ground. Above the membrane, the grade still has to be specified.
Why do people talk about blue or pink foam?
Those colours were brand colours for extruded board, not a kPa class. Grey XPS has replaced some blue ranges. A white sheet can be XPS, and a blue craft block can still lack a grade. A Triplast reviewer said the white sheets are not like dense blue or pink foam.
Is the SuQurtom five-pack that blue foam?
It uses XPS words and the spec line says blue. It states no compressive grade and no density. The title, the spec line and a measured review disagree on size. At £12.59 and three ratings, treat it as a small block you measure, not as floor XPS.
Which foam do model makers carve?
XPS, when the edge has to stay sharp, as with a brick course. EPS suits bulk that will be covered, because the beads crumble. About 33 kg/m³ is Panel Systems’ figure for its Craftfoam sheet. That number is not printed on the SuQurtom listing.
When do you ask for a specified board?
When the sheet sits under a slab, below a damp-proof membrane, in a relevant-building external wall, or wherever a drawing names a kPa and a thickness. The packs here are amazon.co.uk listings with a shared review pool or three ratings. They do not replace that datasheet.
Related pages
Sources
Public UK sources and the amazon.co.uk listings compared on this page. Updated 23 October 2026.
- British Plastics Federation, EPS and XPS (retrieved 23 October 2026)
- BSI, BS EN 13163 (retrieved 23 October 2026)
- Building Regulations 2010, regulation 7 (retrieved 23 October 2026)
- GOV.UK simpler recycling (retrieved 23 October 2026)
- Which? insulation boards (retrieved 23 October 2026)
- Polyfoam XPS, compressive strength (retrieved 23 October 2026)
- HSE PPS1, hot-wire cutting (retrieved 23 October 2026)
- Stylite expanded polystyrene datasheet (retrieved 23 October 2026)