Can You Use A Dehumidifier To Dry Plaster (Explained!)

  • Author: Irene Batres
  • Date: September 26, 2022
  • Time to read: 5 min.
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Drying plaster is an important step in the construction process.

It takes time, and it’s always advisable to let it dry naturally.

The problem is that many buildings have high humidity levels, which make drying difficult.

So can you use a dehumidifier to dry plaster?

In this post, we will adequately answer this question and go over many other frequently asked questions.

Can You Use A Dehumidifier To Dry Plaster

It is not advisable to use a dehumidifier to dry plaster. Doing this interferes with how plaster should dry and cure naturally. By using a dehumidifier, you are hurrying the drying process, and the plaster can either start cracking immediately or over time.

Also, it does not provide a gentle drying process. The air from the dehumidifier is too dry, and it can cause damage to other materials, especially if you have wet insulation or wood in your walls that will also be dried by this machine.

The best way to avoid having humidity problems during construction is through proper site management and proper insulation.

What Setting Should a Dehumidifier Be On To Dry Plaster?

If you have to use a dehumidifier to dry plaster, then make sure the air circulation setting is at 1.

Doing this warms up the air around the walls, so the plaster dries up faster.

You can increase the air circulation setting after the wall has completely dried up (usually 2-3 days).

How Long Does It Take To Dry Out A Wall With A Dehumidifier?

How long it takes depends on a few factors, including the thickness of the plaster and the outside and inside humidity levels.

However, since the dehumidifier speeds up the drying process, you should expect it to reduce the drying by at least one day.

Also, depending on the outside humidity levels, you might need to set the dehumidifier in a different mode or increase its speed.

 Should You Use a Dehumidifier To Dry Plaster?

How To Tell If Plaster Is Dry Enough To Paint

You can tell if your plaster is dry enough for painting by looking at a few things. One, dry plaster is light and has no dark patches.

Two, it is consistent throughout and looks solid. Lastly, it is hard and has no residue.

If, after the drying process, your plaster still looks wet or there are dark patches on it, leave it for a few more days (up to about one week). After this period, if you can’t paint yet, then check again.

Can You Use A Dehumidifier To Dry Paint?

Yes. In fact, more and more paint companies are advising consumers to use dehumidifiers to dry paint. Paint dries up by losing water through evaporation. 

Using a dehumidifier speeds up this process by removing water faster from the air.

A dehumidifier will also help you to avoid paint drips that result from high humidity in the walls.

It is, however, important to remember that even though a dehumidifier speeds up this process and dries paint quickly, it does not ensure quality results.

Drying Plaster Windows Open Or Closed?

Leaving at least one window slightly open will help the plaster dry up faster and better. It allows air circulation while still keeping most of the room’s heat inside.

However, you need to consider which windows you leave open, where they are located and whether or not rain might blow in through them.

If you do end up leaving windows open, make sure to close them before nightfall and cover the opening with thick plastic sheets so no moisture can seep in overnight.

Using A Dehumidifier to Dry Damp Walls (How To)

To dry damp walls with a dehumidifier, you need to be sure that the dehumidifier has a high capacity and can do its job properly.

If your room is small, then no problem. However, if it’s large or you have many walls to dry up, then it might take too long with just one dehumidifier.

Test the humidity levels of the walls in different spots before deciding on the setting you will have on the dehumidifier. If the humidity levels are still high in some parts, then increase the speed of your dehumidifier.

Can You Sleep In a Room That Has Just Been Plastered?

Yes. You do not have to worry about the plaster smell as it is normal and will dissipate within a few days to a week. However, things may feel dump, so it is probably advisable to give the room at least a day before you start using it again.

What Happens When Plaster Gets Wet Before Painting?

When plaster gets wet before painting, it might cause problems like mold formation or bubbling of paints, resulting in discoloration. 

This usually occurs during humid seasons such as spring and summer, where humidity levels rise quite high, especially on walls with poor insulation that let moisture through easily.

What Happens If I Don’t Wait For My Plaster To Dry Before Painting?

It’s very important to let your plastering walls completely dry before applying paint because this will determine how well it adheres to the surface. 

The paint may develop bubbles or peel off. It may also lead to discoloration over time if moisture seeps through the cracks of your paintwork and affects it.

What Is A Good Relative Humidity Level For Drying Plaster?

The best relative humidity range that plaster should be dried at is 60-65%.

This means that there has been an improvement in air quality, and because of this, the rate of evaporation will slow down. 

In addition, if your room gets too dry (less than 40%), then it can cause damage to other materials such as wood or insulation, which are also used during construction.

Final Thoughts- Should You Use a Dehumidifier To Dry Plaster?

While using a dehumidifier to dry plaster is not always advisable, it can help you to dry the plaster up faster and save you some time.

If it’s just a small room, then there should be no problems using one. Be careful not to dry the air too much as this will lead to cracks and other damage.

irene mills author of freshairdevices


Irene Batres is eager to help others create an indoor allergen-free home. She has years of experience testing out air purifiers, dehumidifiers, and other products designed to help with indoor air quality. Learn more about me.