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How to paint concrete

Updated: 23 October 2026

You already have a tin that matches the surface, and the next risk is timing. Amazon fields say full cure in two hours on tins whose makers say 24 or 72 hours, and doorstep reviews describe rain lifting a film that was used too soon. This is how to paint concrete once the job is chosen: wait, clean, coat, and stop. It does not rank the twelve rows in the [concrete paint comparison](/hub/paints-and-varnishes/concrete-paint). Peter F. wrote this on 23 October 2026 from maker pages and the amazon.co.uk fields. We did not paint a test wall. A qualifying purchase through our links can earn a commission at no extra cost to you.

You already have a tin that matches the surface, and the next risk is timing.

Our top picks

Leyland Leyland Granocryl white 2.5 L

Best overall

Leyland Leyland Granocryl white 2.5 L
8.9/10about £15.17
View offer
Ronseal Ronseal Diamond Hard floor paint slate

Alternative

Ronseal Ronseal Diamond Hard floor paint slate
6.4/10about £15.72
View offer
Ronseal Ronseal doorstep paint black 250 ml

Alternative

Ronseal Ronseal doorstep paint black 250 ml
6.7/10about £10.49
View offer
On this page
  1. 1.Sound, dry, and not brand new
  2. 2.Walls
  3. 3.Interior floors and doorsteps
  4. 4.When to stop

Sound, dry, and not brand new

New concrete is still losing water, and it carries a weak dusty skin called laitance. Ronseal's floor page says the concrete should be at least a month old before Diamond Hard floor paint. Watco's preparation notes often put the wait at about six weeks or longer. Do not average those into one figure. Follow the tin you opened. The face has to be sound and dry. Scrape loose material, wash off dirt, and let it dry. An active damp patch or hollow render is outside this method. None of these acrylics is a damp-proofing system. If you are still choosing the tin, use the concrete paint buying guide.

Walls

Exterior masonry paint in this set goes on a wall, render, pebbledash, or concrete board. Plan two coats and keep a wet edge so the white does not flash. Ronseal's doorstep page wants a dry day above 10°C. Use that as the stop for a masonry wall when the Amazon cell is silent. The 2.5 litre Leyland row says dry in 24 hours and full cure in 4 hours. The 5 litre row says full cure in 2 hours. When the listing is shorter than the tin, wait for the longer interval. Sandtex's page excludes common Fletton and engineering bricks.
Leyland Leyland Granocryl white 2.5 L

Testsieger

Leyland Leyland Granocryl white 2.5 L
8.9/10about £15.17
View offer

Interior floors and doorsteps

Ronseal Diamond Hard floor paint is the interior floor tin here. The Amazon row puts both dry time and full cure at 72 hours, and the maker page says heavy traffic after 72 hours. A 750 ml tin covers about 3 square metres with three coats. The usage field says indoor. Do not treat a conflicting exterior line as permission to paint a patio. A doorstep has its own tin. Ronseal's page says two coats and fully hard in 24 hours, on a dry day above 10°C. The Amazon rows say two hours, and reviewers of the 250 ml black tin report rain and flaking. Wait for the maker's 24 hours. The anti-slip claim is not a BS EN 16165 result.

When to stop

Stop if the render is loose, the damp is active, or you are working at height on the wrong platform. Stop if the slab is oily, power-floated, and glass-smooth, or if a car will park on it. Those surfaces need a floor system this masonry set does not describe. The Health and Safety Executive expects you to read the VOC label and to ventilate. Exterior mineral water-borne paints sit under a 40 g/l cap in the VOC Regulations 2012, and the label should show the number. Call a decorator when the wall is listed or salts return. Call a floor contractor for power-floated or contaminated garage concrete.

Common questions

How long should new concrete dry before painting?
Ronseal says at least a month before its floor paint. Other floor makers, including Watco's general preparation advice, often say about six weeks or longer so the slab can dry and the laitance can be removed. Do not average those into one figure. Read the tin in your hand. A new render has its own time on the bag. Paint on green concrete fails because the film traps moisture or bonds to dust.
Do I need a stabiliser?
Use one when the surface is chalky, and when Ronseal's floor instructions call for one or for a thinned first coat on bare concrete. Sound, clean masonry often takes exterior masonry paint without a separate primer. The Leyland rows do not state a primer. A stabiliser will not fix loose render or damp. If the wall dusts heavily after you brush it, stabilise that dust before you spend the tin.
How many coats go on a wall?
Plan two coats of masonry paint. Coverage is about 10 square metres a litre on a smooth face, less on pebbledash. Let the first coat dry for the longer of the times on the tin and on the Amazon row, because those fields clash. A third coat is for a colour that still grins through, not a default.
Can I paint if rain is due tonight?
Not a doorstep, and not an exposed wall. Ronseal wants a dry day above 10°C, with the doorstep film fully hard in 24 hours. Amazon fields that say two hours are shorter than that page, and rain complaints sit on the 250 ml black tin. Leave the job for a clear day. Masonry paint on a wall has the same problem if a shower hits before the film has skinned.
Why did doorstep paint wash off?
The usual pattern on the Ronseal black 250 ml reviews is rain or use before the film has hardened. The listing says two hours. The maker says 4 to 6 hours before foot traffic and 24 hours to be fully hard. Degrease, use two coats, and keep it dry for the longer interval.
What temperature is too cold?
Below 10°C is too cold for the Ronseal doorstep instructions, and it is a sensible stop for the masonry tins as well. A bright afternoon that will fall to 4°C with dew is still a poor window. Cold film stays soft, takes longer to resist rain, and can sit on the surface. Wait for a milder dry spell rather than forcing a weekend slot.

Related pages

Floor paint or masonry paint

Best concrete paint

Concrete paint

Concrete paint buying guide: which tin for the job

Garage floor paint is missing from this concrete set

Sources

Public sources from the research digest, last checked on 22 October 2026. Shelf prices and star lines are the amazon.co.uk figures in the display file. The price band is this set, not a market average. No listing was lab-tested.

  1. VOC in Paints, Varnishes and Vehicle Refinishing Products Regulations 2012, Schedule 2 (retrieved 22 October 2026)
  2. BS 6150:2019 Painting of buildings — Code of practice (retrieved 22 October 2026)
  3. HSE: paint and coatings (retrieved 22 October 2026)
  4. HSE: caution, wet paint (retrieved 22 October 2026)
  5. Ronseal Diamond Hard floor paint (retrieved 22 October 2026)
  6. Ronseal Diamond Hard doorstep paint (retrieved 22 October 2026)
  7. Sandtex smooth masonry (retrieved 22 October 2026)
  8. Amazon.co.uk Best Sellers, Concrete Paint (retrieved 22 October 2026)