Understanding Plaster Drying Times: What to Expect

If you've recently had plastering work done — whether it's a full room skim or a fresh coat on new plasterboard — one of the first questions you’ll have is: how long does plaster take to dry? It’s important to get this right, especially before painting or decorating, to avoid issues like peeling paint, bubbling, or damp patches.

Drying time depends on several factors including the type of plaster used, the surface underneath, the thickness of the layer, and environmental conditions like temperature and ventilation.

Typical Drying Times for Plaster

In general, plaster takes around 3 to 5 days to dry per coat for a standard skim on plasterboard. If you're applying it over a base coat or onto a high-suction surface like bare brick, it could take 7 to 10 days or longer.

Freshly plastered walls will appear dark and slightly damp. As it dries, the colour lightens to a pale, even pink. Only when this colour is fully uniform should you think about painting.

Multi-coat work — such as bonding plus a skim — can take up to two weeks to fully dry.

Factors That Affect Drying Time

Plaster doesn’t have a strict timeline because many conditions can influence how quickly or slowly it dries.

Temperature plays a big role. A cold or unheated room will slow down the drying process, while warmer, well-ventilated spaces speed things up — though it’s important not to force-dry plaster using heaters or dehumidifiers, as this can cause cracking.

Humidity levels also matter. High humidity in the air slows evaporation, while dry air helps the moisture in plaster escape more efficiently. If your property has poor airflow or a damp problem, drying could take much longer.

The type of plaster used makes a difference too. For example:

• Thistle MultiFinish (common in the UK) usually dries within 4–7 days.

• Bonding or backing coats take longer due to their thicker application.

• Lime plaster, often used in heritage properties, can take several weeks to dry fully and must be treated with extra care.

Can You Paint Plaster Before It’s Dry?

No — you should never paint over wet plaster. Doing so can trap moisture inside the wall, leading to bubbling, peeling, or even mould. The golden rule is: only paint when the wall is completely dry, which you’ll know by its even pale colour and dry-to-the-touch surface.

When the wall is ready, always start with a mist coat — a diluted emulsion that allows the wall to breathe — before applying your standard topcoats.

How to Help Plaster Dry (Without Damaging It)

Ventilation is your best friend. Open windows during the day to let moisture escape, and keep the room at a steady, mild temperature. Don’t blast it with heat, and avoid closing the door and trapping all that moisture inside.

A fan in the room can help air circulate, and using an extractor fan in a nearby bathroom or kitchen will also reduce humidity.

If you're in a hurry, resist the temptation to paint early — rushing this stage could mean redoing the entire job down the line.

Final Thought

Plaster takes anywhere from 3 days to 2 weeks to dry, depending on the materials, thickness, and conditions in the room. Be patient, let it dry naturally, and only move on to decorating once you're sure it's fully dry. Taking the time now will save you from cracked walls, damp spots, and costly rework later.