How Long Does Plaster Take to Dry?

Plastering a room in your home creates smooth, finished surfaces which are ready for painting, wallpapering, or panelling once the plaster is completely dry.

You need to ensure that the plaster is dry thoroughly before further decorating. If you don’t, it could damage the plaster, causing cracks and brittleness because of excess damp.

How long does plaster take to dry?

Plaster generally takes around three to five days to dry fully, although thicker applications, poor ventilation, or high humidity can extend drying times to 2 weeks. Plaster is usually ready for decorating when it changes from dark brown to a consistent pale pink colour. Then, you can apply your mist coat of paint or wallpaper.

How long the plaster takes to fully dry can depend on how thick it is, and the conditions of your home. While you shouldn’t try to force the drying time of plaster, there are a few good practices to follow to ensure it dries effectively.

Type of Plaster	Typical Drying Time
Skim coat plaster	2-3 days
Freshly plastered wall	3-5 days
Thick plaster layers	5-14 days
Cold or humid conditions	Up to 2 weeks

 

To mix plaster thoroughly and effectively, you can hire a paddle mixer directly from Speedy Hire online, or visit your local depot.

 

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How can you tell when plaster is dry?

• The plaster changes from dark brown to pale pink.
• There are no darker patches remaining.
• The wall feels dry to the touch.
• The room no longer feels excessively humid.

How to speed up plaster drying

Newly plastered walls typically shouldn’t be hurried through the drying process. Don't rush out to hire a dehumidifier just yet; you should not use a dehumidifier to quicken drying times, only if conditions require one.

If a dehumidifier is needed, ensure it is set on a limit to ensure the room won't go below 55% humidity.

If the plaster dries too quickly, it will suffer from cracks and fragility over time. As a result, you should always plan for it to take around three to five days, or even longer. Bear this in mind if planning time to paint or hiring professionals to decorate.

Plaster can take anywhere up to two weeks to dry fully, depending on the circumstances. If layers are thick, or the air is humid, it can delay the drying time.

Instead of speeding up the drying times, you can create the ideal conditions to give the plaster time to dry.

Tip 1. Ensure the humidity is correct

You have to be really careful before introducing a dehumidifier to your newly plastered home. Take out too much humidity, and the plaster will dry too quickly, causing hairline cracks and brittleness over time.

Plaster needs a humidity of around 60-70% to dry properly, while still staying hydrated enough to dry evenly. If your humidity levels are above 70%, you may wish to hire a dehumidifier to correct this.

Humidity should be higher than 50%.

 

Tip 2. Increase airflow

Try to keep windows and doors open. Hiring a fan can help increase airflow, particularly in winter when opening windows is difficult.

A fan will not absorb excess moisture. Just ensure it is on a low setting so the room doesn’t become too cold.

 

Tip 3. Maintain the temperature

Most homes are usually around 18 to 25 degrees. Keeping the temperature low but comfortable is best for drying plaster.

Too high, and the plaster will dry too quickly and crack. To ensure plaster continues to dry evenly, it requires consistent temperatures and adequate ventilation.

You should turn off central heating in the plastered room to ensure sections near radiators don’t dry too quickly. Instead, hire heaters to maintain a temperature of around 15 degrees in winter or use fans on a cooler setting in summer.

The temperature mustn't drop below 2 degrees when applying and drying plaster. Use heaters on a low setting to maintain some heat.

Common mistakes when drying plaster

Painting before the plaster has fully dried

One of the most common mistakes DIYers make is painting plaster too soon. New plaster needs time for moisture to evaporate naturally. If paint or wallpaper is applied before the wall has fully dried, moisture can become trapped behind the finish, potentially leading to peeling, bubbling, and uneven results. Check out our comprehensive article on how to paint new plaster for more tips.

Using excessive heat to speed up plaster drying

The hotter a room is, the faster new plaster will dry, right? While technically correct, excessive heat can cause sections of your fresh plaster to dry too quickly, increasing the risk of shrinkage cracks. A steady room temperature, good ventilation, and a healthy dose of patience are the most effective ways to ensure your plaster dries properly and stays in good condition for years to come.

Running a dehumidifier without a limiter

A dehumidifier can be great for removing excess moisture and humidity in a room, but if you're not careful, they can cause more harm than good when it comes to a freshly plastered room. If you do need to use a dehumidifier, make sure you use the settings on it to prevent the humidity from dropping too low. Running it for short stints regularly throughout the day can also be a good way of preventing excessively dry conditions.

Ignoring dark patches

Plaster will rarely dry evenly across an entire wall or room. Areas around corners, ceilings, and external walls often take longer to dry due to cold spots or increased moisture. As tempting as it can be to assume these will be fine and get decorating anyway, don't. Painting or wallpapering before these dark patches have disappeared can result in inconsistent finishes and increase the likelihood of issues in the future.

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