How to paint new plaster

By Tom Drake | 17th May 2024 | 5 min read

When a wall has been freshly plastered, extra care needs to be taken to ensure you get the best finish when painting. In this guide, we take you through the steps you need to take to paint new plaster.

Painting new plaster steps:

1. Let the plaster dry
2. Mix up a mist coat
3. Apply mist coat
4. Apply topcoat

1. Let the plaster dry

Before painting your wall, you need to let the plaster dry completely. Painting over plaster when it’s not dry can cause problems later, so if in doubt, always wait until you’re confident it’s dried completely.

As plaster dries, lighter patches will start to emerge across the wall. When the whole wall has turned a lighter, pale pink colour, it’s dry. The drying time of plaster will vary depending on the temperature and humidity of the room. Plaster will usually take at least a week to dry completely, but it can take multiple weeks.

2. Mix up a mist coat

New plaster is porous, so if you paint it with standard paint it will simply be absorbed by the wall. This means you’ll need to apply more coats of paint, and the paint could start to peel later as it dries. To prevent this happening, you need to apply a mist coat first.

A mist coat is a combination of standard emulsion paint and water. When you apply a mist coat, the wall will absorb the water so the paint can adhere to the wall.

To create a mist coat, mix two parts emulsion paint with one part water. When applying your mist coat, try to use a colour that's close to the topcoat.

3. Apply the mist coat

Once you’ve mixed up your mist coat you can apply it to the wall. Applying a mist coat can be messy, so it’s a good idea to protect the floors and any furniture that remains in the room with dust sheets.

You can apply a mist coat with a roller or a paintbrush. A roller will be quicker but will create more mess than if you use a paintbrush. A paintbrush can be used to paint the edges and corners.

Paint with a smooth motion to give even coverage across the wall. You’ll usually only need to apply one mist coat, but you can apply a second if you don’t feel you’ve properly sealed the plaster. If you're using a primer, always follow the instructions on the packaging.

Can I paint straight onto new plaster?

If you paint straight onto new plaster without a mist coat, the plaster will soak up the majority of the paint and you’ll need to apply a lot more coats. The paint may also start to peel as it dries.

When can I paint over the top of a mist coat?

A mist coat will usually take around 24 hours to dry, but drying times will vary depending on temperature and humidity. The mist coat should be dry to touch before you paint over it.