How To Paint Plaster Walls In 5 Easy Steps

New to painting plaster walls? Whether you've got old plaster walls or freshly plastered walls, you might be wondering about the best way to go about painting them.

Here, we'll provide you with everything you need to know about painting plaster walls, including the tools and supplies you need and common questions.

Before you even start preparing your plastered walls for painting, there are a couple of things that you'd need to take into consideration:

  • 1
    Make sure that you're working in a well-ventilated room.[1]
  • 2
    Ensure that you've got the necessary eye protection - a dust mask would be ideal. Especially for dealing with sanding dust.
  • 3
    To protect your dining room during painting, cover any furniture, carpets and switch outlet covers with dust sheets, and tape off any windows and door handles to prevent paint from spilling on them.

Preparing your plaster walls for painting is an important step - especially if you have old plaster walls.

Not only do you have to put more effort into the surface preparation for old plaster walls, but you'll also need to fix all damaged plaster with a high-quality plaster patching compound.

Even though this can be labor intensive, this is definitely a step you shouldn't miss, especially after removing all the wallpaper.

Test the Walls for Lead

Before you even proceed with painting plaster walls, it's essential to ensure that your current old plaster walls are free from paint containing lead. This is because lead was a commonly used paint ingredient in the past, and exposure to it could cause health risks. [2]

To test the plaster walls for lead, you can use an at-home lead paint testing kit before you proceed with any other steps.

Remove Old Paint

Then, it’s time to go ahead and remove the old paint covering your old plaster walls. To do so, you can do so in two ways:

  • Use paint scrapers and sandpaper for chipped and peeling paint to ensure that you've got a surface that's even and free of bumps. You can also use a putty knife to help you with this step.
  • Use chemical strippers if you have relatively intact paint.

Patch and Repair Plaster

Once you've removed the wall of any old plaster, it's time to repair and patch any cracks, nail holes, and damage with a patching compound. While this might be tedious, this is important as any cracks that you have in the walls could spread. This is also a good time to determine if you have loose plaster.

You can fill small cracks with paintable caulk, but if you've got larger holes, you need to use patching compound and sand it like drywall. The ultimate goal of this is to ensure that you've got a perfectly smooth, even surface that's perfect for painting.

With the sanding for larger holes, you can blend patches or new plaster into the old plaster with rough grit sandpaper. You can also apply a thin layer of plaster patching compound on old plaster walls with holes and large cracks with a putty knife.

Make sure that you're applying a thin layer and aren't overapplying. You can always apply a second coat of patching compound if necessary.

While the cracks can be repaired using either plaster or drywall joint compound as mentioned above, they will keep coming back if you don't look at taping them with self-adhesive fiberglass mesh tape.

This mesh tape is easy to use - all you've got to do is cut the mesh tape pieces and overlap them to cover the crack.

After you've got a level surface, smooth the surface with high-grit sandpaper.

Sand Down The Walls

Sanding down the wall is the last step of preparing plaster walls after using a patching compound, and it's essential - especially if you haven't taken care of everything previously.

It's your last chance to level out everything, and you can lightly sand with rougher and finer sandpaper for this.


Painting Plaster Wall: DIY Guide For Beginners

Once you're done with the above, it's time to start painting. Make sure that you've got drop cloths to cover your floors, furniture, and any other surfaces you'd like to keep protected while painting.

Damp cloth or Drop cloths are good for any splatters, drips, and spills that may happen from painting all the walls.

Orange Plaster Wall Design

1. Clean Plaster Walls

Before doing anything, you’d need to go ahead and clean your plaster walls - this is important for both an old and a newly plastered wall. Start by vacuuming any dust that might be on the walls. Then, gently wash down the walls with soapy water and a sponge before allowing them to dry for at least 24 hours.

2. Let the Plaster Dry

One of the most important things to consider when painting newly plastered walls is to make sure that your newer plaster is completely dry before painting. You do not want to be painting on wet plaster. If you do, you could run into adhesion problems and may notice peeling on your walls.

A week should be enough for the wet plaster to completely dry and for all the damp patches to disappear on your newly plastered wall.

You can quicken the process by using a heater or opening a window. While you're waiting for your plaster to dry completely, go ahead and put down dust sheets and tape any fixtures or fittings.

3. Mix a Mist Coat

Before painting, you should prime your freshly plastered wall with a mist coat of paint. It's important to do so as fresh plaster is really dry and porous, so fresh coat would suck out the liquid of your paint and leave you with plenty of mess on your freshly plastered wall.

If you don't want to use a mist coat, you can also use a water-based primer.

A mist coat is made of watered-down emulsion paint. To make it, simply mix three parts emulsion with one part water until it has a thin consistency that's similar to milk. Then, go ahead and apply that mist coat of paint.

As newly plastered walls can be dry and dusty, a mist coat will seal them and get them ready for painting.

You only need to use a basic white emulsion, and you'll be good to go - you don't have to use anything overly fancy. If a mist coat doesn't work for you, a water-based primer would also work well for the wall paint.

4. Apply the Mist Coat

Then you'll go ahead and apply the mist coat. There are two ways that you can go about doing so - a roller or a paintbrush. While a roller would be the quicker method, it can be messy. With a paintbrush, it's more precise but would take longer.

However you choose to apply your mist coat, go ahead and apply it in an upwards motion until you've covered the entire wall or whole wall. As the mist coat can be runny, whenever it drips, go ahead and paint over it quickly.

If it looks patchy, don't worry, as the mist coat is meant to seal the surface but not cover it. After you've applied the mist coat, you would typically spot prime the walls again with a plain base coat.

If you're painting textured plaster walls, remember to use an M or W shape to ensure you're getting into all of the pockets of the textured plaster.

If you'd like, you can also apply white paint to your wall so you can spot any imperfections before painting the wall with your chosen paint finish (Lighther or darker colour).

5. Apply the Top Coat

Once your mist coat has dried, it's time to go ahead and start painting. To begin, you'll go ahead and apply your first coat of paint. Since you've already sanded the wall and done the necessary prep, this step should be exceptionally easy. Remember to apply the first coat of paint in a V motion.

While you might think that one coat of paint would be sufficient, you should apply a second coat of paint. Applying a second coat of paint will help with a more even finish or satin finish and will ensure that your plaster wall is looking perfect.


Tools & Supplies To Paint New Plaster Walls

Below are some of the tools and supplies you'll require when it comes to painting new plaster walls.

Working with Putty Knife

Paintbrush

One of the most important things you'd need is a paintbrush. When choosing your paintbrush, you'd want to get one that picks up and lays off more paint than a normal brush. By doing so, you'll be able to get the paint job done quickly without having to worry about compromising the quality of the finish.

It should also be compatible with all types of fresh paint - be it oil paint or water-based paint, and allow you to apply paint smoothly.

Roller Cage

A roller cage, also known as a paint roller, allows you to quickly and evenly paint an entire wall surface with ease. Roller cages are designed to be used with a roller sleeve and will help ensure that you get new paint on the walls in no time at all.

Roller Sleeve

When it comes to a roller sleeve, selecting the right one is crucial as it's the part to which the paint is applied. It comes in all sorts of shapes and materials, and the length of the material can also help with determining the overall outcome.

If you're looking for a soft, even finish, you should be painting with a ⅜ inch to ½ inch roller sleeve.

Sandpaper

While sandpaper may not be required for every project, you need it for any minor imperfections, such as rough spots or dark spots on the walls. If you don't end up sanding your walls, you'll end up dealing with issues while applying the paint.  

Putty Knife

You’ll absolutely need a putty knife - especially if you plan on removing old paint or filling cracks or holes. Not only is a putty knife ideal for scraping and removing paint, but it can also be ideal for helping to fill cracks or holes in your walls.


What Kind Of Paint Is Best On Plaster Walls?

Primer

When it comes to painting on plaster walls, you also need to take the appropriate primer into consideration. Ensure that you're using the best high-quality primer; ideally, you should select an oil-based primer.

A high-quality primer, especially an oil-based one, is a must as it's much better at preventing any stains from water and other materials from showing through the painted surface -  a problem you'll commonly find in plaster walls.

If you're painting on old plaster walls, a high-quality oil-based primer is also an absolute must.

You can consider a stain-blocking primer as it can help with keeping your plaster wall both smudge, water stain, and blemish-free. In addition, a stain-blocking primer also gives better film leveling and durability.

Paint

For the paint, you'd want to opt for a matte finish paint or flat finish paint if you're painting on old plaster walls. These types of paint are better as they don't show imperfections as much.

For newly plastered walls, a semi-gloss paint or eggshell paint would be ideal as it's resistant to scuffs and general wear and tear. Since it also has a washable surface, it's suited to families with children.

In general, a latex paint specifically designed for plaster walls would also work well. Not only does latex paint have good adhesion, but it will also help with preventing cracking and peeling. If you'd like, you can also use water-based paints on plaster walls instead of latex paints or semi-gloss paint.

How Many Coats of Milk Paint Will You Need? This is what the walls are looking like after one coat of milk paint. Obviously they need another coat, but the coverage is pretty good.

Tow Colored Plaster Wall Designs

Common Questions On Painting Plaster Walls

What are plaster for walls made of?

Plaster for walls is usually made of lime or gypsum mixed with water, and reinforced with sand or cement. Horsehair may also be added to strengthen the plaster and prevent cracks.


Are plaster walls the same as dry wall?

No, it is not the same as plaster walls. Plaster walls have a more durable finish and dry much harder than drywall.


Can you paint directly on new plaster?

Wait for new plaster to dry completely before painting on it to achieve a smooth finish and prevent peeling.


How long do I have to wait before I can paint new plaster?

Wait for the new plaster to dry completely before painting. Depending on the conditions, it can take one to six weeks.


What is a mist coat?

Mist coat is a diluted emulsion paint that functions as a primer and provides moisture to the walls, facilitating the adhesion of the top coat.


Does a new plaster need a mist coat?

Mist coat needed for new plaster. Helps seal wall, prevents paint failure and adhesion problems.


What happens if you don’t prime plaster?

Not priming plaster can cause peeling paint, especially in humid conditions, and make cleaning walls after the paint dries more challenging.


Why does paint peel off plaster walls?

Peeling of paint on plaster walls can occur due to multiple layers of paint being applied on old walls without allowing proper drying time between coats. This can cause bubbling paint which eventually leads to peeling.


Conclusion

There are quite a few things modern homeowners need to take into consideration when it comes to painting both your old and new plaster walls. Whether it be to prep plaster walls sufficiently or applying a mist coat prior to painting.

Once you've got the more tedious portions out of the way, however, you can be assured that you'll have perfectly painted plaster walls without any surface flaws.

References:

1. https://www.cpsc.gov/s3fs-public/painting.pdf
2. https://www.dcceew.gov.au/environment/protection/chemicals-management/lead/lead-in-ho