Used for the protective or decorative coating of walls and ceilings, plaster is one of the most popular construction materials in the UK.
No matter what type you use, you might be wondering how long plaster takes to dry before you can paint or drill holes in it to hang furniture and objects.
Plaster takes about two to four hours to dry to touch. However, it must cure properly before painting, drilling, or fitting kitchen cabinets on it. Depending on plaster type, temperature, air moisture level, ventilation, and how many layers you applied, plaster can take anywhere from seven to 21 days to fully dry.
The table below shows you an overview of how long the different kinds of plaster take to dry and cure:
|Plaster Type||Dry (Setting) Time (25°C)||Cure Time (25°C)|
|Bonding plaster||1.5 - 3 hours||4 - 7 days|
|Browning plaster||1.5 - 2 hours||4 - 7 days|
|Hardwall plaster||2 - 5 hours||7 - 14 days|
|Tough coat plaster||2 hours||4 - 7 days|
|DriCoat plaster||24 hours||7 - 21 days|
|Base filler plaster||1 - 2 hours||4 - 7 days|
|Board plaster||1.5 hours||3 - 5 days|
|One Coat plaster||4 hours||4 - 10 days|
|Skim plaster||2 - 3 hours||4 - 7 days|
|Finishing plaster||1 - 3 hours||4 - 7 days|
|Magnetic plaster||2 - 3 hours||4 - 7 days|
How Long Does Undercoat Plaster Take To Dry?
Undercoat plaster is the type of plaster that goes directly onto masonry materials. Its role is to create a smooth surface for the finish materials whilst also adding a layer of insulation and protecting the masonry.
This undercoat is commonly used for low suction materials, such as concrete blocks. It can take between 90 and 200 minutes to set and needs at least four days to dry fully.
A quick-setting type of bonding plaster is also available. This takes only 60 minutes to set, but you should still allow for four to seven days of dry time.
Is used as an undercoat for high suction materials, such as stone or Thermolite blocks.
Like bonding plaster, it is pink or grey in colour and is fully dry when the shade becomes uniform and pale (about seven days). The setting time is slightly shorter than bonding plaster.
Is a high-impact undercoat for medium suction backgrounds like brick and Aircrete blocks.
Setting time can vary from 160 to 300 minutes, depending on the brand. It can take up to 14 days to dry completely. A light colour is an indicator of dryness.
Tough Coat Plaster
This undercoat is an excellent choice for tough conditions other plasters can’t handle, such as frozen walls. It also provides some fire protection.
It generally sets in 120-130 minutes, but it needs at least seven days to dry completely.
A speciality plaster type, DriCoat, is used for replastering after fitting a new damp-proof course or on walls that have dried up after flooding.
It sets in about 24 hours, but you should leave it for at least one full week to dry completely before applying a finishing product.
How Long Does Finishing Plaster Take To Dry?
Finishing plaster goes on top of the undercoat variety and can be decorative on its own or used as a base for paint or wallpaper.
Base Filler Plaster
One of the quickest-drying plasters, it is used for filling cracks and holes and repairing walls. It sets in about an hour and generally needs four to seven days to dry before sanding, painting, or wallpapering.
Like all plasters, the longer you leave it to dry, the better the end result once you apply the decorative finish.
It goes on top of plasterboard after installation, smoothing out the joints and fastener recesses.
It sets very fast, generally in an hour, and also cures faster than other types. You can normally apply the decorative finish in three to five days.
One Coat Plaster
As it says on the tin, one-coat plaster only requires one coat. However, this doesn’t shorten the drying time.
Like all plasters applied over an undercoat or masonry material, it requires up to seven days to dry fully in optimal conditions. In poor weather or high humidity, it can take up to two weeks to dry.
The setting time is also longer compared to other plaster types – about 240 to 300 minutes. It can also be used for undercoating.
Skim plasters are designed for fast application on large surfaces through spray skimming. They provide a smooth, inert surface suitable for the application of decorative finishes. It is particularly indicated for wallpapering.
Skim plaster sets in two to three hours and requires up to seven days to dry completely.
This plaster type is generally suitable to use on all backgrounds for finishing and repairing jobs. Two or more coats may be required for finishing.
A quick setting time between one and three hours ensures quick application. It fully dries in about seven days.
One of the most sought-after plaster types, it can turn a wall into a magnetic board. The thick compound sets relatively fast, about 200 minutes from application.
Let it dry completely for at least four days – preferably longer – before painting the surface with chalkboard paint or other suitable coats.
How Do You Know When Plaster Is Dry?
A visual inspection is the easiest and most reliable way to tell whether plaster is completely dry or not.
All plaster types have a dark colour when wet. As they dry, the shade lightens up until it becomes a pale pink or grey (sometimes green).
When the plaster appears to be a solid, uniform, very light colour, it is most likely dry. It still needs drying if it is dark or has darker patches.
How To Speed Up Plaster Drying?
Speeding up the plaster drying process is generally not recommended. Plaster that dries too fast can crack or chip, and it might not bond to the substrate.
That said, you can speed up drying time by increasing ventilation and temperature.
Open the windows and use a space dehumidifier if it rains or there are high levels of air moisture in the room. A space heater can also speed up the process.
How long should plaster dry before painting?
Plaster should dry for at least three or four days before painting. An undercoat should dry for at least seven days before applying finishing plaster.
Do I have to mist coat new plaster?
Yes. A mist coat is watered-down paint that soaks into the plaster and improves results when painting with undiluted emulsion.
Applying a mist coat can enhance bonding and prevent paint from flaking or peeling. Let the mist coat dry for at least 24 to 48 hours before applying the topcoat.
How long does plaster take to dry in winter?
Plastering work carried out in winter generally requires about 50% more drying time compared to plaster applied in good weather. You should wait for at least 14 to 21 days before finishing the surface.
Plaster in moist environments, such as the bathroom and kitchen, can take longer to dry regardless of the season.
Most plaster products become touch-dry quickly after application (about two to three hours). However, it can take up to three weeks for them to dry completely.
Since the actual dry time varies based on environmental conditions and layer thickness, the easiest way to tell when your plaster is dry is by checking out its colour.