Prepping your walls for painting
By Tom Drake | 22nd April 2024 | 4 min read
If you want to achieve the best finish when painting your walls, preparation is key. In this guide, we take you through everything you need to know to get your walls ready for a fresh coat of paint.
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Safety first
When preparing your walls, you should keep the room you’re working in as ventilated as possible. Wear an appropriate mask when sanding and wear protective gloves when using sugar soap.
1. Fill holes and cracks
The first step to prepping your walls for painting is repairing and filling any holes or cracks.
First, remove loose debris or plaster from the crack and use a vacuum to remove dust. You can then clean the crack with sugar soap to completely remove any remaining dust which could prevent the filler from sticking to the wall.
Next up, take a flexible filling knife and push filler into the gap or crack until it's smooth with the wall. Once you've completely filled the hole, leave the filler to dry.
Lastly, sand the filler with fine sandpaper until you achieve a smooth, flat finish.
2. Sand the walls
Once you’ve filled in any cracks, take a piece of fine sandpaper and lightly sand all the walls and any peeling paint. Sanding will give the wall a texture that will help the new paint bind to the surface.
3. Clean the walls
Cleaning your walls will help remove grease, crayon, fingerprints and any other dirt that’s been left behind after sanding.
Apply sugar soap to the wall, then wipe it down with a sponge. Once you’ve cleaned all the walls, give them a final clean with warm water to remove any soap traces.
4. Let the walls dry
Once you've finished sanding and cleaning, let the walls dry completely before applying the first coat of paint.
Do you need to use primer when painting over old paint?
Primer can help paint bond to the wall to give you a better finish. If you’re painting on walls that are poor quality, changing paint type, or painting over a dark colour with a light colour, a primer can help you achieve a better finish.
If your walls are in a good condition and you're using a similar paint to the existing paint, you may not need primer. Always check the instructions on your chosen paint for guidance on using primer.
How to prepare a newly plastered wall
Before you can paint a newly plastered wall, you need to add a primer and undercoat. If you skip this step, the plaster will soak up the paint like a sponge, so you’ll need to add more coats than you might otherwise need to.
Remember to allow all new plaster to dry completely before decorating. A plastered wall is dry when any dark patches shrink away, or when it turns a light pink/grey colour.
How to prepare a previously wallpapered wall
You can paint over old wallpaper but to achieve the best finish, you should remove it first. If you need to remove wallpaper, take a look at our guide.
Once you’ve removed the wallpaper, sand the walls with light sandpaper to remove any remaining debris and give the paint a better surface to adhere to. You can then use sugar soap and a sponge to clean the walls before giving them a final clean with warm water to remove any remaining soap.
Allow the walls to dry completely before painting.
That concludes our guide to prepping your walls for painting. Although it may seem like more work in the short term, these steps will help you achieve a quality finish that you can be proud of.