Waiting for fresh plaster to dry can feel like one of the slowest parts of any renovation. The walls are finished, you’re ready to start decorating, but painting too soon can cause problems with the final result.

While you can’t make plaster dry instantly, you can create better conditions for it. Temperature, ventilation and humidity all affect drying plaster, and managing these properly can help keep your renovation moving without trying to force the process.

One option is to use a dehumidifier. But how does this work, and when drying plaster, should windows be open or closed? Here’s what you need to know.

How Long Does Plaster Take to Dry?

There isn’t one set drying time for fresh plaster. How long you’ll need to wait depends on several factors, including:

• The type and thickness of the plaster
• How large an area has been plastered
• The temperature inside the property
• Humidity levels
• Ventilation and airflow

A thin skim coat will generally dry faster than thicker areas of plaster, while a cold, humid room is likely to take longer than a warm, well-ventilated one.

You can usually see the drying process happening. Fresh plaster starts darker and gradually becomes much lighter and more uniform in colour.

Don’t rush to paint the moment the surface starts looking lighter, though. Different sections can dry at different speeds, and you want the plaster to be thoroughly and evenly dry before you begin decorating.

Drying Plaster: Windows Open or Closed?

Search for advice about drying plaster windows open or closed and you’ll probably encounter conflicting answers. That’s because there isn’t one rule that works in every situation.

Opening windows can be helpful because fresh plaster releases moisture into the surrounding air as it dries. Ventilation allows that humid air to leave the room and be replaced with fresh air.

However, opening every window isn’t automatically better.

If it’s particularly wet or humid outside, you may simply be introducing more moisture into the property. During colder weather, leaving windows wide open can also make the room considerably colder, which may slow the drying process.

The goal is to create controlled conditions rather than simply maximise ventilation.

Opening windows periodically when the outside air is relatively dry can help. During very damp weather, controlling the humidity inside the room may be more effective.

And if you’re using a dehumidifier, keep the windows and external doors closed while it’s running. Otherwise, the machine will continually be trying to remove moisture from new air entering the property.

Can You Use a Dehumidifier for Drying Plaster?

Yes, a dehumidifier can be useful when drying freshly plastered rooms, particularly where humidity is high or natural ventilation is limited.

As plaster dries, the water it contains evaporates into the surrounding air. Eventually, the air in the room can become increasingly humid. A dehumidifier extracts this excess moisture, helping to maintain conditions that allow the natural drying process to continue.

This can be particularly useful for:

• Renovations taking place during wet or colder weather
• Basements and other poorly ventilated spaces
• Properties where opening windows isn’t practical
• Larger projects where several walls or rooms have been plastered
• Building projects where managing moisture levels is important

The important distinction is that a dehumidifier should be used to manage the environment, rather than aggressively force the plaster to dry.

Can You Dry Plaster Too Quickly?

When you’re working to a renovation deadline, it can be tempting to turn the heating up as high as possible and try to get everything dry overnight.

That’s not necessarily the best approach.

Applying excessive direct heat can cause the surface to dry much faster than the plaster underneath. In some circumstances, drying plaster too aggressively can contribute to cracking or an uneven finish.

Avoid positioning powerful heaters directly against newly plastered walls or trying to create extremely hot conditions.

Instead, aim for a comfortable, reasonably consistent room temperature combined with sensible ventilation and humidity control.

You’re helping the plaster dry naturally, not trying to bake it dry.

What’s the Best Way to Help Fresh Plaster Dry?

Creating the right environment is usually more effective than relying on one single method.

• Maintain a consistent temperature. Gentle ambient warmth can support drying without exposing the plaster to excessive direct heat.
• Provide appropriate ventilation. Allow humid air to escape when outdoor conditions are suitable.
• Manage humidity. If moisture is building up inside the room, a dehumidifier can help extract it.
• Keep windows closed when using a dehumidifier. This creates a more controlled environment and allows the machine to work efficiently.
• Allow enough time. Even if the surface looks dry, don’t rush into applying paint or wallpaper before the plaster has dried evenly.

When Is Dehumidifier Hire Worth Considering?

If you’re renovating one property or completing occasional building work, buying specialist drying equipment may not make much sense.

This is where dehumidifier hire can be particularly useful.

You can hire the equipment while the work is taking place and return it once the property is dry, rather than paying for a machine that then needs to be stored for the rest of the year.

Hiring also means you can choose a dehumidifier suited to the size of the room or project. A small bedroom and a large renovation site won’t necessarily require the same equipment, so getting the right capacity can make a considerable difference.

It’s a practical option for homeowners, landlords, decorators and contractors who need temporary help managing moisture during renovation work.

Create the Right Conditions and Let the Plaster Do the Rest

When it comes to drying plaster, patience is still important. Trying to force the process with extreme temperatures isn’t necessarily going to give you a better or faster result.

Instead, focus on creating the right conditions: a sensible temperature, controlled airflow and manageable humidity.

And when it comes to drying plaster with windows open or closed, remember that the answer depends on what else you’re doing. Natural ventilation can be helpful when conditions outside are suitable, but if you’re running a dehumidifier, close the windows and doors so it can efficiently remove moisture from the room.

If humidity is slowing down your renovation, Chilly Pepper Hire can help you find the right temporary dehumidifier for the job. Get in touch with our team to discuss your space and find a practical drying solution.