How Long Does Plaster Take To Dry?

how long for plaster to dry

This page was last updated on 1 May 2022

How Long Does Plaster Take To Dry In 2022?

Types of plaster

The most common type of plaster mix is a sand and cement mortar that dries harder than clay or mud. It is available in powder form and can be mixed with water to create a mixture that dries and hardens into a solid wall.

Other plasters include lime plaster, gypsum plaster, and stucco (a mixture of sand, cement, and lime).

How long does plaster take to dry?

So how long does it take? How long plaster takes to dry depends on a number of factors. For example, the type of plaster you choose, how thick the layer is you are placing on the wall, and how many coats you apply.

For instance, a thin coat of gypsum takes around 30-60 minutes to fully dry while a thicker coat of exterior stucco might take days or even weeks. In general, though, it will take at least 24 hours for any type of new plaster to fully cure before it can be painted or grouted. An additional 24 hours should be added on top of that time if additional layers and then a skim coat are placed over an existing layer of fresh plaster.

Entire walls with two or three layers of plaster, often known as backing plaster, will take even longer to dry properly. Plasterboard takes less time to dry than backing plaster as a general rule of thumb. 

The amount of time it takes for the plaster to fully dry also depends on the climate you are in since heat and humidity both help evaporate water more quickly. It will take longer to dry during cold weather or if you are working on a cool, dehumidified construction site. Central heating can also have an impact. 

Most paints can be applied on top of new plaster as long as it has had 24 hours to cure before you start painting over it. If using grout, wait at least two weeks before applying so that the walls have some time to completely dry out again.

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Why do you need to wait?

People might be tempted to apply paint or grout onto wet plaster to save time, but that can have negative consequences.

Emulsion paint won’t bond properly with the surface of the wall if it is not completely dry, which means it will peel off much easier. Grout will also be much less durable over time if applied too soon before the plaster has had a chance to dry out completely.

Nailing or screwing into walls that are not fully dried yet can also cause the new layer of plaster over them to cave in on itself due to water damage from moisture seeping through any cracks. 

This often causes various issues later on in the wall’s lifespan so it is important to know how long plasterboard takes to dry and plan your project accordingly.

How long before painting over new plaster?

As long as you have allowed the plaster on the newly skimmed walls to cure for at least 24 hours, painting over the surface shouldn’t be a problem.

If you want to be sure, it a good idea is to wait at least two weeks before applying any grout onto still-drying walls. High humidity in kitchens and bathrooms can sometimes cause water based paints to warp and peel so it is always worth playing it safe in a freshly plastered room. 

In a Hurry? How to dry plaster quickly

If you’re in a hurry to get the plaster to dry, there are a few things you can do to help speed up the plaster dry time:

  • Increasing ventilation in the room by opening windows and doors
  • Use fans to circulate the air
  • Turn on dehumidifiers
  • Use radiators to help speed up the drying process

A dehumidifier is a great option for reducing the amount of humidity in a room. You will notice that the drying process of the new plaster is enhanced significantly. If you’re working on multiple projects at once, consider renting one for your space.

Opening at least one window during humid times of day will also help to remove moisture more rapidly. Exposing plaster to direct sunlight may also cut down drying time by half or more.

Preparing plaster for painting

Sanding down the surface of fresh plaster creates an optimal base for normal emulsion paint or grout to be applied on top. Make sure the wall is smooth and flat before beginning either process.

Cleaning up any dust created by light sanding will make it easier to paint later on, so take care not to omit this step.

How long does plaster last?

Plaster actually has a longer lifespan than most people give it credit for. It can last several decades in certain conditions which makes it very useful in construction projects that require solid walls that are easy to clean and maintain over time.

When applying plaster in areas where moisture is plentiful, consider waterproofing the exterior of the wall to prevent any damage over time.

how long for plaster to dry

Why does plaster crack when drying?

The most common problem homeowners face when working on plaster walls is cracks that form as it cures. These often appear as long, horizontal lines across the surface of the wall and can worsen over time if homeowners do not take preventive measures.

Ceilings are especially prone to cracking since there is more weight bearing down on them than walls and they cannot flex under any pressure.

Cracks in plaster will always appear eventually if you fail to take the necessary steps to ensure they do not develop. However, this process is slow and will usually only be noticeable after a few months or even years. The longer you wait before applying another layer on top of fresh plaster, the better your chances are of avoiding this type of accident.

The most common type of plaster mix is a sand and cement mortar that dries harder than clay or mud. It is available in powder form and can be mixed with water to create a mixture that dries and hardens into a solid wall.

How to fix cracks in plaster walls?

If you have cracks in your plaster walls, there are a few things you can do to fix them:

  • Try to fill the crack with a plaster repair kit. This can be found at most hardware stores and usually comes with everything you need to make the repair.
  • If the crack is too wide, use a metal patch to fill it. Cut a piece of metal that is slightly larger than the crack, then bend it into a U-shape so that it fits snugly into the opening. Use screws or nails to fasten it in place, then fill the gap with plaster.
  • If the crack is deep, use a vinyl patch kit instead. 

In some cases, prevention will be your only option since the crack may have been too severe to get rid of completely without making it bigger. In such a case, make sure you use plaster primer before applying any new material over top.

If you’re going through all the trouble of preparing a wall for painting or grouting, there’s no point in cutting corners at the last minute. Picking the right construction adhesive is also essential to making sure your new layer of plaster over the crack stays in place.

plaster drying time

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Why isn’t the plaster drying?

There are several factors that can keep the plaster from properly drying out.

Ceilings are especially vulnerable to this problem since they usually have more moisture seeping through them than walls do. If you’re not draining any water in your bathroom, kitchen, or laundry room sink, make sure to hook up a PVC pipeline directly overhead with an emergency shut off valve in case of overflow.

Extreme humid conditions can also interfere with plaster drying since the moisture in the air will prevent it from curing properly.

Finally, plaster needs to breathe so avoid sealing in any rooms completely unless you plan on turning them into bathrooms where humidity is necessary for proper sanitary purposes.

Anything that can get in the way of the plaster drying out completely (like humidity, excess moisture, or poor ventilation) will make it more probable for cracks to form or paint to peel. This is why you need to be especially careful how you treat your newly plastered walls if you plan on painting plaster.

What does dry plaster look like?

Dry plaster will look like a solid, white surface. It will be smooth to the touch, and there should be no visible signs of moisture and no dark patches on the surface. 

Note that plaster changes colour from a dark fawn to a light pink (or light creamy colour) when drying.

If you notice a plaster wall still feels wet, leave it be until all the moistness has been completely evaporated so you don’t cause more damage by attempting to work with wet plaster. 

If it has a uniformed pale pink complexion with no dark patches then this colour change should make you feel confident applying your first coat of oil based paint. 

what does dry plaster look like

Can you sleep in a plastered room?

Yes, as long as you can walk on the floor normally with no concern of cracking the fresh plaster. As a general rule, plan to wait at least 48 hours before removing any caution tape from freshly plastered walls and leave them alone until you know for sure they have completely dried out so there’s no chance of causing more damage by walking or sleeping on top of wet plaster.

When it comes to ceilings, it may be best to wait a bit longer depending on how much moisture still needs to escape. You’ll want them to feel rock solid before allowing yourself or anyone else into the room who is not there specifically for construction purposes only.

If you’re too eager to start using your newly plastered ceiling as soon as possible, it’s better to place a few fans in the room and aim them upward near the location where the plaster was applied so any excess water can escape directly up and out of your home. Even if you’ve had the room plastered recently, this should encourage it to dry faster. 

What is a mist coat?

A diluted mist coat is a thin layer of plaster that goes on first and helps keep the majority of moisture from seeping through your walls. 

Plastering typically has a learning curve that takes some time to adjust to and it’s important to not be overly eager about getting new projects complete sooner than they were designed.

Mist coats are extremely important when it comes to protecting your newly plastered wall against excess moisture because they allow water vapour in but block it from fully seeping through the walls.

The mist coat is also designed to help keep any excess moisture trapped within your plaster so it can easily evaporate out through the surface of the wall.

how to dry plaster quickly

When doing projects like this at home, it’s best not to rush or skip steps that could cause more damage later on down the road because you’ve put in a lot of time and effort into creating something worth hanging onto for as long as possible.

How to apply a mist coat to plasterwalls

Using a mist coat will save you time and money by helping the overall drying process go much faster without compromising the integrity of your work.

Applying a mist coat is very simple. All you need is a brush or roller and some plaster. You can either apply it directly to the surface of the wall or use it as a primer before applying the final coat of plaster.

If you’re going to be painting over this, or want a more even finish to your wall, it’s best to apply the mist coat with either a brush or roller where the thicker final layer of plaster can be applied with a trowel.

You’ll also need to tape off any electrical outlets so there’s no chance for moisture damage which could cause an electrical fire later on down the road.

After misting is complete and dry (this usually takes about 20 minutes) then you can use lath boards (if needed) to smooth out thick plaster applications before applying your final coats.

Final Thoughts

So how long does it take? The amount of time that it takes for plaster to dry depends on how thick of a coat you are applying and the type of plaster mix that you choose. Generally, the thicker the coats of plaster, the longer the plaster drying times. 

 Instead of trying to estimate the drying time of your new plaster, check that the colour has changed from a dark pink to the light pink of dry plaster and make sure that there are no dark patches. This way, your new plaster will have its best chance of avoiding complications down the line. 

There are a number of things you can do to speed up the drying process but it is always best not to rush things or take any shortcuts. Good ventilation, opening windows,  ambient temperature and adequate time to air new plaster are key to avoiding paint flaking and reducing the plaster drying time. 

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Article author

James Lloyd

I am the primary writer and author for Help and Advice, having originally helped start the site because I recognised that there was a need for easy to read, free and comprehensive information on the web. I have been able to use my background in finance to produce a number of articles for the site, as well as develop the financial fitness assessment tool. This is a tool that provides you with practical advice on improving your personal financial health.

Outside of work I am a keen rugby player and used to play up to a semi-professional level before the years of injury finally took their toll.  Now you are more likely to see me in the clubhouse enjoying the game.

Email – james@helpandadvice.co.uk

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Frequently Asked Questions

How long does plaster take to dry?

So how long does it take? How long plaster takes to dry depends on a number of factors. For example, the type of plaster you choose, how thick the layer is you are placing on the wall, and how many coats you apply.

Why do you need to wait?

People might be tempted to apply paint or grout onto wet plaster to save time, but that can have negative consequences.

How long before painting over new plaster?

As long as you have allowed the plaster on the newly skimmed walls to cure for at least 24 hours, painting over the surface shouldn’t be a problem.

Why does plaster crack when drying?

The most common problem homeowners face when working on plaster walls is cracks that form as it cures.

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