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Foam window seal or gasket: which one belongs on your frame

Updated: October 2026

A foam roll near £5 and a black coil near £20 look like one draught fix in two sizes. The foam window seal or gasket choice is a choice of fixing. Foam sticks to a bare rebate, and a gasket pushes a foot into a groove. Buy the gasket if a short sample seats, and buy the foam only when there is no usable groove and the gap matches the roll. Figures are amazon.co.uk listings on 15 October 2026, read by Products Compared, with no lab test. A purchase through our links can earn a commission at no extra cost to you. The wider set is in our [window seal comparison](/hub/door-and-window-security/window-seal).

A foam roll near £5 and a black coil near £20 look like one draught fix in two sizes. The foam window seal or gasket choice is a choice of fixing. Foam sticks to a bare rebate, and a gasket pushes a foot into a groove.

Our top picks

Storm Patrol Storm Patrol uPVC gasket, 25 m, black

Best overall

Storm Patrol Storm Patrol uPVC gasket, 25 m, black
7.5/10about £20.18
View offer
YANKUIRUI YANKUIRUI D-profile foam seal, 6 m, white

Rank 2

YANKUIRUI YANKUIRUI D-profile foam seal, 6 m, white
8.6/10about £4.49
View offer
UPSEN UPSEN D-profile foam seal, 10 m, white

Best value

UPSEN UPSEN D-profile foam seal, 10 m, white
8.3/10about £4.99
View offer
On this page
  1. 1.If a sample seats, buy the gasket
  2. 2.If there is no groove, foam is the short-life stick-on
  3. 3.Rubber D is a third case
  4. 4.Neither product, on a sash or over a vent

If a sample seats, buy the gasket

If a short piece of gasket seats in the groove, buy the gasket. Rubber that is brittle, has left the channel, or still draughts after a clean needs replacing, as The Advanced Group describes. Foam over that groove adds thickness, and too thick a strip can stop the window shutting. Storm Patrol was about £20.18 for 25 m on 15 October 2026, rated 4.5 stars from 306 reviews, for a stated 3–5 mm frame, and it publishes no foot width. If the foot kinks or only goes in when stretched, skip the coil. Tarqite was about £7.89, with 4.5 stars from nine reviews and no stated gap. The best window seals page explains that skip.

If there is no groove, foam is the short-life stick-on

No usable groove, plus a gap inside the stated range, means foam, and you should treat it as a short-life fix. The Energy Saving Trust calls it cheap and short-lived. UPSEN was about £4.99 for 10 m and states about 3.5–5 mm. YANKUIRUI was about £4.49 for 6 m and states 3–6 mm. Bynsaer states 3–5 mm at about £4.49, but one review put the unsplit roll at about 3 m. GUKOY is flat 3 mm tape with no stated gap, so it is not the default. Try about 50 mm on a clean, dry rebate. Measuring in full stays in the window seal buying guide.
Storm Patrol Storm Patrol uPVC gasket, 25 m, black

Testsieger

Storm Patrol Storm Patrol uPVC gasket, 25 m, black
7.5/10about £20.18
View offer

Rubber D is a third case

Esufeir is stick-on rubber D, not a push-in gasket. It was about £7.99 on 15 October 2026, stated at 2.5–6 mm. The rubber feels firmer than UPSEN or YANKUIRUI foam where those gap bands overlap. One review reported a back door that became too tight to lock. A groove that accepted the Storm Patrol sample remains a gasket job.

Neither product, on a sash or over a vent

Brush strip is the sash product. The Energy Saving Trust calls foam a poor sash seal on an uneven gap. Leave trickle vents, air bricks, extractors and combustion air open. Mist between the panes is a failed unit, and a seal leaves that cloud in place. If a sample seats, buy the gasket. If there is no usable groove and the gap matches a foam listing, buy the foam as a short-life fix. Fitting the coil is on the uPVC window seal replacement page.

Common questions

My uPVC rubber has gone hard. Should I stick foam over it?
Replace rubber that is brittle, has left the channel, or still draughts after a clean. Foam over a groove that still takes a foot adds thickness, and the casement may not close. If a short piece of Storm Patrol seats and the handle shuts, buy that coil, about £20.18 for 25 m with a 3–5 mm frame range. If the foot will not enter, use foam only when the gap matches the roll.
When is a foam window seal the right buy?
Foam is the right buy when there is no usable groove and the gap sits in the roll's stated range. UPSEN states about 3.5–5 mm and was about £4.99 for 10 m. YANKUIRUI states 3–6 mm and was about £4.49 for 6 m, both on 15 October 2026. Test about 50 mm, and stop if the window will not close. The Energy Saving Trust says this foam may not last long.
Is a rubber D strip the same as a push-in gasket?
Esufeir is self-adhesive rubber D at about £7.99, stated at 2.5–6 mm, and it sticks to the rebate. Storm Patrol and Tarqite are push-in coils that need a groove. One review reported a back door too tight to lock. That firmness does not make Esufeir a channel gasket.
How long does foam draught tape last?
The Energy Saving Trust says self-adhesive foam may not last long, and Historic England also calls foam short-lived. Neither guide gives a year count for these rolls, and we have not wear-tested them. Replace the strip when it packs down or peels.
Which costs less per window, a £5 roll or a £20 coil?
These listings give a pack price, not a price per window. On 15 October 2026 YANKUIRUI was about £4.49 for 6 m and Storm Patrol was about £20.18 for 25 m, about 75p and about 81p a metre. UPSEN at about £4.99 for 10 m is about 50p a metre. The cheaper pack only helps if the fixing matches the frame.
Will foam clear condensation between the panes?
Moisture between the panes means the sealed unit has failed. Foam and a gasket only close the gap around the opening. The cloud inside the glass stays until the unit is replaced. Draught-proofing tape is the wrong repair for failed double glazing.

Related pages

What draught-proofing windows costs

Window seals

Best window seal for a groove or a stick-on rebate

Window seal buying guide: measure the gap in millimetres

How to fit a window seal so the handle still locks

Replace a uPVC window seal when the rubber is hard

Sources

Public UK sources named in the research digest. Listing prices and ratings are the amazon.co.uk figures saved on 15 October 2026.

  1. Energy Saving Trust — Draught-proofing (retrieved October 2026)
  2. Centre for Sustainable Energy — DIY draught-proofing (retrieved October 2026)
  3. GOV.UK — Approved Document F (2026) (retrieved October 2026)
  4. BSI — BS EN 12365-1:2003 gasket and weatherstripping (retrieved October 2026)
  5. Seals Direct — How to measure a replacement glazing gasket (retrieved October 2026)
  6. Fixtrade — How to replace the rubber seal on uPVC windows (retrieved October 2026)
  7. Historic England — HEAG084 Draught-proofing windows and doors (retrieved October 2026)
  8. Consumer Rights Act 2015 (retrieved October 2026)