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How to choose an acrylic sealant

Updated: 23 October 2026

A white cartridge that says flexible, waterproof or silicone-acrylic still does not tell you whether it will take emulsion on a skirting or wash out of a bath. Acrylic sealant, also sold as decorator's caulk, is a water-based paste for a quiet gap you will usually paint. It shrinks as water leaves a deep fill, and it does not spring back like silicone. Check chemistry, movement class, wet or dry, then paint time. The five amazon.co.uk listings, from £3.76 to £6.20 on 19 October 2026, sit on the [acrylic sealant comparison](/hub/fillers-adhesives-and-sprays/acrylic-sealant). A qualifying purchase through our links can earn us a commission at no extra cost to you.

A white cartridge that says flexible, waterproof or silicone-acrylic still does not tell you whether it will take emulsion on a skirting or wash out of a bath.

Our top picks

Soudal Soudal decorator caulk, white, pack of 2

Best overall

Soudal Soudal decorator caulk, white, pack of 2
8.8/10about £6.18
View offer
Everbuild Sika Caulk Once white, pack of 2

Rank 2

Everbuild Sika Caulk Once white, pack of 2
9.2/10about £5.38
View offer
Everbuild Everbuild Everflex 175 acrylic sealant, white, 300 ml

Rank 3

Everbuild Everbuild Everflex 175 acrylic sealant, white, 300 ml
8.2/10about £6.20
View offer
On this page
  1. 1.What acrylic sealant is for
  2. 2.The four checks on the sheet
  3. 3.Gap, colour and pack
  4. 4.How the five listings split

What acrylic sealant is for

Acrylic sealant fills a gap that barely moves and that you expect to hide under paint or paper. Skirtings, architraves, plaster cracks and the still joint between a frame and the wall are the jobs. A bath, a shower and an opening sash are not. The paste skins as water evaporates. Soudal's decorator sheet states shrinkage under 25 percent, so a deep screw hole can sink. Silicone cures with moisture, stays elastic, and will not take emulsion. If the title mixes silicone into an acrylic name, read the material field. If the joint stays wet, read acrylic sealant versus silicone before you buy.

The four checks on the sheet

Read movement, then interior or exterior, then water, then paint. F 12.5P means about 12.5 percent of the joint width, and the sealant takes a new shape rather than springing back. Soudal's UKCA note: F is façade, INT interior, EXT exterior, P plastic. A sliding sash or a floor joint is out of range. Caulk Once's page states F 12.5P, paint in about an hour and full cure in 3 to 5 days. These amazon.co.uk bullets do not say outside. Soudal is about 10 percent and interior. Everflex 175 is plus or minus 7.5 percent, internal and external. All three sheets exclude continuous immersion. A 15-minute Amazon cell is a skin, not full cure.
Soudal Soudal decorator caulk, white, pack of 2

Testsieger

Soudal Soudal decorator caulk, white, pack of 2
8.8/10about £6.18
View offer

Gap, colour and pack

Soudal's DIY cartridge caps the gap at 10 mm. A 15 mm chase is not one fat bead from that tube. White is for paint. Brown is a visible match on a dark internal frame. The 151 brown title is internal only, and the listing says it is not water resistant. A short-dated second tube wastes the saving on a two-pack.

How the five listings split

Caulk Once is the top pick for a joint you will paint: the review file, the hour paint line and 12.5P on the manufacturer page. Skip a hairline, and skip it when the Amazon bullets must say outside. Soudal is the best value: higher stars, a 10 mm gap, and a bead you can paper. The title says acrylic silicone and the material field says acrylic. Skip it outside or in the wet. Everflex 175 is the single for a painted exterior frame. Skip it for a shower. The 151 brown is an internal colour match. The £4.18 cartridge, 13 reviews and a brand field that prints WELLA, is not a pick.

Common questions

What should you read on an acrylic cartridge before you buy it?
Read the chemistry, then the movement class, then F-INT or F-EXT-INT, then whether constant water is excluded, then the paint time. Silicone, hybrid polymer and liquid rubber appear in the same search. If the class is missing, do not invent it from flexible or waterproof. The sheet or the conformity mark is the source. An Amazon cure cell of 15 or 20 minutes is not that source.
Is decorator's caulk the same product as acrylic sealant?
Yes, when both are a water-based acrylic for a decorating joint. Shops use decorator's caulk, frame sealant and acrylic sealant for that family. The split that changes the buy is interior against exterior, and a dry paintable joint against a wet one. Sanitary silicone only shares the word caulk. Check the material line before you treat two white tubes as the same thing.
What does 12.5P change about the joint you can fill?
12.5P means plastic behaviour at about 12.5 percent of the joint width. The bead can take a small movement and then stay in the new shape. That suits a quiet skirting crack or a static frame edge. It does not suit a working façade, a floor joint or a sash that must slide. Everflex 175's plus or minus 7.5 percent is a tighter limit on the same idea.
Can you use any acrylic sealant outside?
No. F-INT, or a title that says internal use only, stays indoors. The 151 brown cartridge is that case, and it is not water resistant. Outside, you want F-EXT-INT, and you still keep the fresh bead out of rain and frost. Caulk Once's page allows façade use indoors and out, but these Amazon bullets do not say outside. Below about 4 °C to 5 °C, wait.
Does waterproof on an Amazon bullet mean a shower?
No. Waterproof and water resistant are the fields Amazon printed, not a sanitary rating. The sheets for Caulk Once, Soudal Decorators Caulk and Everflex 175 exclude continuous immersion. Everflex reviewers describe wash-off in a shower and failure on a bath edge. A joint where water sits needs a sanitary sealant, usually silicone under EN 15651-3.
How wide a gap is a decorator cartridge actually for?
The Soudal pack states a maximum gap of 10 mm. A deep gap needs a backer rod so the bead is not one plug of paste. Wider gaps around a new frame are often a different sealant. Do not copy 10 mm onto the other four listings, which do not state a maximum. White is for paint. Brown is only for a bead that will show on a dark internal frame.

Related pages

How to apply decorator's caulk

Best acrylic sealant

Acrylic sealant

Acrylic sealant vs silicone for paint or wet joints

Acrylic sealant for window frames: still, dry gaps

Sources

Public UK sources used for this comparison. amazon.co.uk prices, stars and review counts were taken from the listings on 19 October 2026.

  1. Soudal Decorators Caulk technical data sheet (retrieved 19 October 2026)
  2. Soudal Decorators Caulk product page (retrieved 19 October 2026)
  3. Sika Caulk Once (retrieved 19 October 2026)
  4. Everflex 175 acrylic sealant data sheet (retrieved 19 October 2026)
  5. Soudal UKCA markings explained (retrieved 19 October 2026)
  6. 151 brown frame sealant safety data sheet (retrieved 19 October 2026)
  7. Acle Parish Council draught-proofing note (retrieved 19 October 2026)
  8. amazon.co.uk listings for the five ASINs in this set (retrieved 19 October 2026)