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Best carpet underlay for the room you are fitting

Updated: October 2026

You want one roll for a named room, not a catalogue of every foam on amazon.co.uk. The best carpet underlay in this set depends on that room. A bedroom or lounge that is not on heating can use a light 10 mm or 12 mm polyurethane roll, if the door still clears. A box room is often better on a 5 m² sheet than on a 15 m² roll you will mostly throw away. A flight of stairs, a flat with a noise clause, or underfloor heating is a reason to walk away from this shortlist. Nothing here is the best underlay in the UK. The full grid is the [carpet underlay comparison](/hub/flooring/carpet-underlay). The order of checks is the [carpet underlay buying guide](/hub/flooring/carpet-underlay/sub/carpet-underlay-buying-guide). Products Compared read these listings on 19 October 2026. We did not test them in a lab.

You want one roll for a named room, not a catalogue of every foam on amazon.co.uk. The best carpet underlay in this set depends on that room.

Our top picks

FloorPro FloorPro 10 mm 5 m²

Best overall

FloorPro FloorPro 10 mm 5 m²
9.6/10about £27.50
View offer
SIXNEA SIXNEA 12 mm PU underlay

Best value

SIXNEA SIXNEA 12 mm PU underlay
9.4/10about £48.99
View offer
247Floors 247Floors PU foam 10 mm

Alternative

247Floors 247Floors PU foam 10 mm
9.4/10about £54.95
View offer
On this page
  1. 1.A bedroom or lounge that is not on heating
  2. 2.A small room that does not need 15 m²
  3. 3.The budget sheet, and the comfort premium
  4. 4.Who should skip this shortlist

A bedroom or lounge that is not on heating

If the room is a bedroom or a lounge, the floor is not heated, and you need about 15 m², the shortlist is a light polyurethane roll at 10 mm or 12 mm, with a door check before you commit. SIXNEA is the best value pick in this comparison: 12 mm recycled PU, a stated 15 m², catalogue size 1100 by 137 by 1.2 cm, listed weight 14 kg, about £48.99, about £3.27 a square metre, and 4.7 from 1,686 reviews. Reviewers describe a springy feel and a price below carpet-shop underlay. Hard nubs from the recycled foam come up in reviews, one person tore the sheet while laying about 9 m² alone, and the title’s “UK manufactured” line is a claim, not a test we repeated. No tog and no end-use class are printed. 247Floors is the 10 mm alternative when you want a slightly lower stack. It states 11 m by 1.37 m, 15.07 m², about £54.95, about £3.65 a square metre, catalogue weight 10 kg, and 4.7 from 571 reviews. A bedroom review compared it with a previous 7 mm layer and called it softer and warmer. A fitting note says the blue face goes down and that scissors were kinder than a Stanley knife. Deep marks under movable furniture are the other limit. Royale, Flooring Online’s 15 m² red roll and SnugStep are all 12 mm at about £52.50, with their own gaps: Royale’s 1 kg catalogue weight is unusable, the two Flooring Online star lines are one shared review file, and SnugStep’s 39 reviews include lumps of solidified foam. Grandismo is 12 mm and 10 m² at about £39.50 if the room is nearer 10 m². Its heating question is unanswered because there is no tog.

A small room that does not need 15 m²

A box room, a cloakroom or a short landing does not need a 15 m² roll. The FloorPro 10 mm polyurethane sheet is the top pick in this comparison for that job: 1 m by 5 m, 5 m², about £27.50, about £5.50 a square metre, 4.8 from 52 reviews, the highest score in the set. Reviewers mention an easy cut, a thickness that still feels soft, and at least one use on stairs and a landing. The stair sentence on the title is still seller text. There is no BS EN 14499 class, no tog and no decibel figure. The roll is 1 m wide, so a wider room needs more seams than a 1.37 m sheet. The 8 mm FloorPro roll is the same 5 m² footprint at about £25.95, about £5.19 a square metre, with 4.6 from 59 reviews. One buyer who ordered 8 mm wrote that 10 mm might have been better. Choose 8 mm when the door gap is tight. Flooring Online’s 5 m² red roll is 12 mm at about £39.99, about £8.00 a square metre, model AMZ-Underlay-143. That is a small-roll premium against the same brand’s 15 m² sheet at about £52.50. The 4.6 from 422 line matches the larger ASIN’s review text, so you cannot treat it as a separate test of the 5 m² size.
FloorPro FloorPro 10 mm 5 m²

Testsieger

FloorPro FloorPro 10 mm 5 m²
9.6/10about £27.50
View offer

The budget sheet, and the comfort premium

The lowest rate in the set is not the best value pick. FloorPro’s polyethylene roll is about £25.99 for a stated 15 m², about £1.73 a square metre, with 3.9 from 83 reviews. The title says 7 mm, the catalogue says 6 mm, and one buyer measured 5 mm. Reviews describe a ribbed face, and one report says half a roll arrived melted with holes through it. A fitter’s review says it is not for cushion-floor vinyl. It can be a basic layer if you have already accepted a thin polyethylene sheet under carpet. It is not a polyurethane cushion. Plushwalk is the comfort premium: 12 mm memory foam, 11 m by 1.37 m, 15 m², about £119.99, about £8.00 a square metre, 4.7 from 184 reviews. Reviewers often say a cheap carpet feels much softer. The seller bullets claim a damp-proof layer, 49 dB, 3.5 tog and a test to BS 5808:1991. Those figures are seller claims on the Amazon page. Wilsons’ own specification sheet also lists 12 mm at 3.5 tog, which is a separate document and not a lab check we ran on the parcel. At 3.5 tog the sheet is already over a 2.5 combined heating limit before you add a carpet, so it is a comfort listing for an unheated room. One buyer needed three deliveries before an undamaged parcel arrived. The catalogue weight of about 1 kg conflicts with a 15 m² roll and should be ignored.

Who should skip this shortlist

Skip the comfort foams if you are fitting stairs or a busy hall and you wanted a printed class or a density. “Suitable for stairs” on the FloorPro bullets does not create a BS EN 14499 class. LD/U, the Floorwise light-domestic mark, is not a stair grade, and these pages do not print LD/U either. An example of what a printed PU spec looks like is Interfloor’s Omega 10 sheet: GD/U, 10 mm, 2.4 tog, 38 dB. You will not find that block on these Amazon bullets. Skip them for underfloor heating. Ten listings print no tog. Plushwalk’s seller 3.5 tog fails a 2.5 combined limit on its own. A decibel claim, including Plushwalk’s 49 dB, is not a tog and is not Approved Document E compliance for a flat. Crumb rubber and sponge rubber are not stocked here. If that is the job, leave this basket. The tog limits are on carpet underlay for underfloor heating. A qualifying purchase through our links can earn a commission at no extra cost to you.

Common questions

What is the best carpet underlay in this set for a bedroom?
For an unheated bedroom of about 15 m², SIXNEA is the best value roll: 12 mm recycled PU at about £48.99 with 4.7 from 1,686 reviews. 247Floors is the 10 mm option if you want less build-up, at about £54.95. Both still need a door check, and neither prints a tog or an end-use class. If the bedroom is nearer 5 m², the FloorPro 10 mm roll is the top pick instead, because you are not paying for 10 m² of offcut.
Is the cheapest roll per square metre the best value?
No. The polyethylene FloorPro sheet is about £1.73/m² and 3.9 from 83 reviews, with a thickness the title and the catalogue do not agree on. Best value here means the lowest rate among the full-size PU rolls that still score well, which is SIXNEA at about £3.27/m². A trade guide of roughly £6 to £9/m² is a shop band, not a price on these listings.
Are the two Flooring Online listings two different products in the reviews?
The sizes differ. One is 15 m² at about £52.50, model AMZ-Underlay-145, with a usable catalogue weight of 19.2 kg. The other is 5 m² at about £39.99. The review text and the 4.6 from 422 line are the same file. Count that sample once. Shared comments include a thick feel, foam that damages easily before the carpet is down, and grippers raised by 10 mm.
Does a 4.8-star score beat a thicker roll?
The FloorPro 10 mm roll’s 4.8 from 52 reviews is why it is the top pick for a small unheated room. It does not beat a 12 mm roll on cushion, and 52 reviews are a smaller sample than SIXNEA’s 1,686. Stars are not a wear test and not a stair class. If you need 15 m², the higher star line on a 5 m² roll is the wrong comparison.
Which rolls should I skip for stairs, a noise clause, or heating?
Skip all eleven for a stair class, because none prints BS EN 14499. Skip them for a lease that wants a tested decibel result. Skip them on underfloor heating: the missing tog is a gap, and Plushwalk’s claimed 3.5 tog is already high. A bedroom without those constraints is the job this shortlist can actually answer.

Related pages

PU foam vs rubber carpet underlay

Carpet underlay

Carpet underlay buying guide: thickness and cover

How to fit carpet underlay inside the gripper

Carpet underlay for underfloor heating: tog first

Sources

Public UK sources listed in the research digest. Listing prices, stars, and review counts are from amazon.co.uk on 19 October 2026.

  1. BEAMA underfloor-heating guide — floor covering and the 2.5 tog combined limit (retrieved 19 October 2026)
  2. Nu-Heat — carpet and underfloor heating (retrieved 19 October 2026)
  3. Approved Document E — resistance to the passage of sound (retrieved 19 October 2026)
  4. NBS — BS EN 14499:2024 textile floor coverings, classification of carpet underlays (retrieved 19 October 2026)
  5. Floorwise recommendation guide — end-use class labels (retrieved 19 October 2026)
  6. Interfloor Omega 10 specification — example PU underlay (retrieved 19 October 2026)
  7. Carpetshire — thickness by room as a rule of thumb (retrieved 19 October 2026)
  8. Homebuilding — 8 mm, 10 mm, and 12 mm comfort map (retrieved 19 October 2026)