Typical drying times
| Type of work | Typical drying time |
|---|---|
| Skim coat over plasterboard or sound plaster | About 3 days to a week |
| Thicker work, such as full re-plastering on brick or block | Around 4 weeks |
| Lime plaster | Longer than gypsum; lime sets slowly and should never be rushed |
These figures come from common trade guidance, such as Screwfix's guide on how long to wait before painting new plaster. Cold, damp weather slows everything down.
Why thickness matters
A skim is thin: British Gypsum's guidance for its finishing plaster gives a total of at least 2 mm across two coats. Full re-plastering, such as float and set on bare masonry, builds up a much thicker backing coat first, and all of that water has to leave the wall.
How to tell plaster is dry
- Colour. Wet plaster is dark brown or grey. Dry plaster is an even pale pink.
- Even all over. Darker patches mean those areas are still drying, often in corners or behind furniture.
- Feel. Dry plaster feels solid and dry to the touch, not damp.
Helping it dry, without causing problems
- Ventilate. Open windows and doors where you can.
- Keep the temperature steady. Gentle, even heat is fine.
- Don't blast it. Putting a heater or fan right up against fresh plaster can make it dry too fast and crack.
- Use a dehumidifier in cold, damp weather if the room stays wet.
Painting new plaster
New plaster is very absorbent, so the first coat needs to be thinned to soak in and bond. This is often called a mist coat. A common mix is around three parts paint to one part water, but follow the paint maker's instructions. Use a breathable emulsion for this first coat, not a vinyl or wipe-clean finish, which can trap moisture and peel. Once the mist coat is dry, paint as normal.
Render needs to dry too
The same applies outside. New render must be fully dry before it's painted, or the paint will fail. If your render is going to be painted, ask how long to leave it. See our house rendering service.
Frequently asked questions
Can I paint plaster after 24 hours?
Not usually. Even a thin skim normally needs several days. Painting too soon can trap moisture, and the paint may bubble or peel.
Why is my new plaster still patchy after a week?
The darker patches are still drying. This is common in cold rooms, corners and on outside walls. Give it longer and keep the room ventilated.
Can I wallpaper new plaster?
Yes, once it's fully dry. New plaster usually needs sizing or sealing first so the paste doesn't soak straight in.
How long does lime plaster take to dry?
Longer than gypsum. Lime hardens slowly by reacting with the air, so it needs gentle, steady drying and shouldn't be forced.
Need walls or ceilings plastered?
See our plaster skimming service, or send us photos for a free quote.
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