Can You Paint Plasterboard When It’s Old And Flaky? Find Out Here!

Did you love your plastered wall at first, but now it looks flaky or dirty? Painting is the answer to your problem! And while many homeowners know how to paint new plasterboard, the process is quite different for an old one! Don’t worry; we are here to help!

Old plasterboard ready to be painted

Still, wondering if you can paint over plasterboard? The short answer is yes, you can, just like you’d paint drywall or a ceiling! But as with all DIY projects, there are some tips and tricks to achieving a great finish. You need to do some things first if you want to paint straight onto the plasterboard paper surface. Then, you can start painting! Keep on reading to find out all you need to know to get the smooth finish you want for your old plasterboard walls!

Which side of the plasterboard should you paint?

For many years, the plasterboard sheet’s grey side was for plastering and its white side for painting. But recently, this has changed; now, the white side is used for everything! For extra information, you can ask your plasterer or check a bare plaster. Sometimes you may see a note printed on one surface of the board, saying which side to use. 

What paint to use? 

Looking for the right paint for your project? Go for good quality paint, like a mist coat, that will need fewer coats, will last longer and look better than a typical one. Also, make sure that it has these features: 

  • It’s breathable or lime-based to prevent moisture.
  • Watered-down emulsion paint acts as a primer and is usually called a mist coat. High-quality matt emulsion paint allows the substrate to breathe, helping the drying process. 
  • Choose a light coloured matt to provide a good base for your finishing top coat paint.
  • DON’T use silk or vinyl paints since they can easily flake or peel off.
  • You can also use specialist paints if you are in a real hurry and cannot wait for your walls to dry out naturally.

What you’ll need for your painting project

Planning is essential to all DIY projects! Gather your materials and tools before you start preparing your walls and painting to have them handy. This will save you a lot of time on the go. Here’s a list of all the things you’ll need:

  • Hammer
  • Work light
  • Scraper
  • Plaster jointing compound
  • Mesh tape
  • Putty knife
  • Fine-grit sanding block
  • Sanding pole
  • Clean cloth or vacuum
  • Caulking gun 
  • Latex painter’s caulk
  • Painter’s tape
  • PVA primer
  • Paint pail
  • Angled paintbrush
  • Paint roller
  • Paint thinner(for oil-based primer) or denatured alcohol (for shellac)
  • Paint extender
  • Paint
  • 150-grit sandpaper or sander

A woman's hand with a brush and water-based paint. Roller and brush for painting walls.

Preparing the room and your old plastered walls

Painting your old wall in a smooth, clean way can take a bit of effort, but the final result is well worth it. It’s best to start by repairing and prepping the wall and then coating it with primer before moving on to painting it. Follow our step-by-step guide to prepare your wall the right way!  

Step 1: Prepare the room

Move your furniture to the room’s centre and then cover the floor with drop cloths. Remove any pictures and switch outlet covers off the walls. Finally, remove any nails with a hammer’s claw end.

Step 2: Find any imperfections

Go over all of the wall’s surfaces with a work light to find any imperfections. If you see holes, cracks, or dents, place a small piece of painter’s tape on them or circle them with a pencil.

Step 3: Remove flaking pieces

Using a scraper, remove crumbled, flaking pieces. Then, spot-prime the areas you scrape to ensure the adhesion of the patching compound.

Step 4: Apply filler to the holes and large cracks in the plaster 

Apply plaster patching filler to any screw holes and large cracks using a putty knife. To do so:

  1. Cut a mesh tape piece the appropriate size to fit and place it over your patched area.
  2. With the putty knife, apply a thin layer of patching compound over the tape.
  3. Allow the patch to dry completely

Step 5: Sand the patched areas & apply a second layer of patching compound

  1. With a fine-grit block, sand the patched areas. Use a pole with paper attached at its end to reach the walls’ tops.
  2. Apply a second layer of patching compound.
  3. Allow it to dry thoroughly.
  4. Sand it smooth to the surface. 
  5. Remove the dust with a clean cloth or vacuum. Any dust left on your wall will stick in the paint and lead to a bumpy final surface. 

Closeup of repairman hand plastering a wall with putty knife or spatula

Step 6: Use sealer to small cracks and sand

  1. With a caulking gun, apply a bead of latex painter’s caulk to small cracks.
  2. Sand your walls with a fine-grit sanding block to smooth and dull its surface. 
  3. Wash the walls using soapy water and allow them to dry completely.

Step 7: Mask with painter’s tape

After you wipe the dust from wood trim and facings with a damp, clean cloth, mask the crown moulding and baseboard trim with painter’s tape.

Step 8: Select the right primer

Applying primer is vital because it helps smooth out your wall and allows the paint to bind more fully. 

  • If you are going to use dark paint, choose a tinted primer
  • If you are worried about mildew, use a moisture-barrier primer.
  • Select an odour-blocking primer if you are worried about the wall absorbing smells, like in a kitchen space.

Pro Tip: According to service contractors and decorators, PVA primer works great on fresh plaster walls. It is also way cheaper than a regular primer. 

Step 9: Apply a single coat of primer

  1. Pour your primer into a paint pail. 
  2. Outline the walls’ perimeter with primer using an angled brush
  3. Cut in the corners where 2 walls meet and everywhere else a roller can’t fit.
  4. Insert a medium-nap roller cover onto your roller handle and place a paint pan liner in a paint pan. 
  5. Pour a manageable amount of primer into your pan. Submerge the roller into the pan and roll it back and forth over the grid lines to distribute the primer evenly on it. 
  6. Apply 1 coat of primer to the walls. 
  7. Continue until the entire wall is covered and looks smooth.
  8. Allow the primer to dry completely
  9. Repeat the procedure to apply a second coat of primer. 
  10. Allow it to dry completely.
  11. Your primer should be thoroughly dried within 24 hours. If you wait longer than 2 days to apply the topcoat of paint, you’ll miss out on the primer’s extra binding properties.

Step 10: Clean the primer from your paintbrush and paint rail

  • To clean up oil-based primer, use paint thinner.
  • Use denatured alcohol to clean shellac.

Step 11: Mix in a paint extender

  1. Before you start painting, add a paint extender or conditioner into your buckets. Follow the bottle’s instructions to determine how much you need to add to each bucket. 
  2. Mix thoroughly with a mixing stick before pouring it out in a rolling pan. 

How to paint on old plaster wall

You are now ready to complete your DIY project. This is the fun part, so make sure to pick a colour you love and enjoy! All you need to do is roll and brush on 2-4 paint coats. Follow our step-by-step guide and enjoy the view of your refreshed plaster wall!  

Painter Cutting In With A Brush to Paint Garage Door Frame

Step 1: Paint around the wall’s edges with a brush

  1. After you’ve poured a bit of paint into the pan, dip the bottom of your brush into it. 
  2. Use smooth strokes to apply a wide band of paint around the wall space’s outer edges.
  3. To keep the paint from dripping off the brush, lightly bump the brush’s sides against the roll pan’s sides after loading it up with paint.

Step 2: Apply the paint with a roller to the middle sections of the wall 

  1. Choose a roller with a thin, 10 mm nap made out of lambswool or mohair to minimise splatter.
  2. Roll the roller in the pan until it is just coated with paint. 
  3. Place the roller against the wall and apply paint in smooth, even moves
  4. Continue until the whole wall is coated.
  5. Give it 24-48 hours to fully dry.

Step 3: Sand with 150-grit sandpaper between coats of paint

Once the first coat of paint has dried, go over the entire space with 150-grit sandpaper. Doing so will help your next coat to adhere more fully to the prior one.

Step 4: Paint 1-2 more coats

A single coat of paint may fade through in patches over time. To prevent this, repeat the painting process until you have 2-3 coats of paint on the wall. When you are done with your final coat, allow the walls to dry completely before replacing wall hangings and outlet covers.

couple painting wall white, happy couple, man on ladder painting with roller

As you can tell, the answer to your question of if you can paint plasterboard is positive. You can do that as a solo activity or as part of a restoration project. Use your favourite colour and make any room look great! Just keep in mind; you should not take any shortcuts in the prep work, and you should plan before you start painting. After you are done, go on and decorate your living room, or any room, to make your house feel like a home! 

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