Can You Use A Dehumidifier To Dry Plaster? A Troubling Question Answered

People resort to dehumidifiers for various reasons. Some people use it to prevent mold and dust mite growth, while others use it to protect furniture. There are also a proportion of people who are curious about if they can use a dehumidifier to dry plaster. 

No, using a dehumidifier to dry plaster is not recommended because it can weaken the plaster and cause cracks.

In this post, I’ll explain why using a dehumidifier is a bad idea and share some tips for speeding up the drying process.

How long does it take for the plaster to dry?

The primary reason why people consider using a dehumidifier for plaster is that they assume it will take a long time for the plaster to dry. 

The truth is that it all depends. Some plasters can dry overnight, while others may take several months to completely dry. Many factors will affect the time length. 

If you paint the plaster in summer, it is going to dry faster than in winter because the temperature plays an important role in the speed of drying. However, you should avoid direct sun exposure, because it will lead to the wet plaster drying too fast. 

The humidity is also crucial. The evaporation speed will be limited by the humid environment and that’s why the plaster in the basement will dry more slowly than that in the regular bedroom. 

Furthermore, a layer with a thickness of 4″ will dry slower than a layer with a thickness of 1″ because it contains more moisture particles.

Besides, the components of your plaster matter. Polymer, for example, usually dries very slowly, whereas gypsum dries much faster.

The wall material also impacts how many days you have to wait. The gas silica walls are usually set faster than other types.

Best ways to dry your plaster

Even though it could be slow, drying your plaster naturally is your best bet. This method can ensure the plaster can get dried both on the surface and inside, reducing the chances of cracking and peeling in the future. 

Opening the windows and doors can assist in this process by boosting air circulation. If there is not adequate airflow, you can turn on your fan. In this way, the moisture level will not be changed tremendously. 

Another way to accelerate this process is by making use of heaters. You can place a few of them around the job site, allowing the moisture to evaporate a bit quicker. This method is better to use in winter whereas using a fan is more sensible in summer.

Can you use a dehumidifier to dry plaster faster?

You may have noticed that I don’t include a dehumidifier as a proper way to dry the plaster. Yes, basically, it is not advisable to do it.

This is due to the fact that the dehumidifier will take away the moisture on the surface and make it harden much faster than the inside. It also prevents the moisture inside from going out.

However, the moisture will eventually evaporate from inside, causing bubbling, cracks, peeling, and other water damage. You may not notice any signs initially, but they can appear down the road. 

This conclusion is proven by many experienced plasterers despite many developers will use a dehumidifier to finish the project quicker. 

It is better to wait a few days instead of doing the job again in the near future. 

How to tell if the plaster is dry?

Please be patient! Only paint after the plaster has completely dried. Otherwise, the wall might look molded or flaky.

Wet plaster is typically darker in color than dry plaster. If there are still a few brown patches on the wall, this indicates that it has not yet dried.

When every part of the plaster turns pale pink, it means the plaster is ready to be painted.


Dehumidifiers are good at removing excess moisture, however, they can’t be used anywhere.

Using a dehumidifier to dry plaster is not a good idea because drying plaster too fast can lead to a lot of adverse effects. Since the moisture inside can’t evaporate naturally before the surface is cured, it will be expelled in the future which will cause cracks or peeling in the future since it has to find a way to come out. 

Just be patient when drying the plaster. Drying it naturally is the best way, and opening the doors and windows can help to dry it faster. 

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Liz Yang is the founder of Airsmartly. She has been working at home for a few years and realizes that the performance of the HVAC system plays such an important role in our life. She has tested a lot of products in person, like humidifiers, air purifiers, dehumidifiers, and ACs, and wants to share tips about using or troubleshooting these products with you. Her uncle is an HVAC expert with over 30 years of experience in the field, and often offers assistance when she is unsure how to handle a situation. He is also in charge of reviewing the articles on this site.

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