How to Paint a Room Like a Pro
A beginner-friendly guide to getting smooth, streak-free walls every time.
Difficulty
Easy
Time
1 day per room
Cost
£50 - £150
Before You Start
Ventilate the room by opening windows. Wear old clothes and safety goggles when sanding. If your house was built before 1980, test for lead paint before sanding - you can buy test kits from any DIY store.
Painting a room is one of the most satisfying and cost-effective ways to transform your home. A single room can be completed in a day if you prepare properly. The secret that professionals know is that 80% of a great paint job is in the preparation - not the painting itself. Rush the prep and you will see every flaw once the paint dries. Take your time and the result will look like you hired a decorator.
What You Will Need
Tools
- - Paint roller and tray
- - 2-inch angled brush (for cutting in)
- - Sandpaper (120 grit)
- - Filler knife and filler
- - Masking tape (FrogTape recommended)
- - Dust sheets
- - Step ladder
- - Extension pole for roller
Materials
- - Emulsion paint (2.5L covers ~30m2)
- - Primer/undercoat (if bare plaster)
- - Sugar soap
- - Fine filler (Polyfilla or similar)
- - Clean cloths
Step-by-Step Instructions
Clear and Protect the Room
Move furniture to the centre and cover with dust sheets. Remove light switch covers and outlet plates. Lay dust sheets along the skirting boards and tape them down so they do not shift while you work.
Fill Holes and Cracks
Use a filler knife to press fine filler into any nail holes, cracks or dents. Overfill very slightly because filler shrinks as it dries. Allow at least two hours to dry fully before sanding.
Sand the Walls
Once filler is dry, sand it flush with 120-grit sandpaper. Lightly sand the entire wall surface to create a key for the new paint. This makes a huge difference to how well the paint adheres, especially on previously glossy surfaces.
Clean the Surfaces
Wipe down all walls with a damp cloth and sugar soap solution. This removes grease, dust and nicotine stains that would prevent paint from sticking. Let walls dry completely before painting.
Mask Off Edges
Apply masking tape along the ceiling line, skirting boards, door frames and window frames. Press the edge down firmly with a filler knife to prevent paint bleeding underneath.
Apply Primer (If Needed)
Fresh plaster, bare wood or stained areas need a coat of primer first. Use a mist coat (paint diluted 70/30 with water) on new plaster. Allow to dry for at least four hours.
Cut In the Edges
Using your angled brush, carefully paint a 5cm strip along all edges - ceiling line, corners, around sockets and along skirting boards. Work in sections of about two metres at a time so you can blend the brushwork into the rolled sections while both are still wet.
Roll the Main Wall
Load your roller evenly and apply paint in a W or M pattern, then fill in with straight, overlapping vertical strokes. Work from top to bottom. Do not press too hard - let the roller do the work. Reload frequently rather than trying to stretch the paint too far.
Apply the Second Coat
Wait at least four hours (check the tin) before applying a second coat. Use the same technique. Two thin coats always look better than one thick coat. For bold colours, you may need a third coat.
Remove Tape and Tidy Up
Remove masking tape while the final coat is still slightly tacky for the cleanest lines. Pull at a 45-degree angle away from the painted surface. Refit socket and switch covers once fully dry.
Pro Tip: The W Technique
When rolling, paint a large W shape on the wall first, then fill it in without lifting the roller. This distributes paint evenly and prevents roller marks and streaking.
Pro Tip: Avoid Lap Marks
Always maintain a wet edge. If you stop mid-wall and the paint dries, you will get visible overlap lines. Finish one complete wall before taking a break.
Common Mistakes to Avoid
- - Not filling and sanding first - every bump and hole shows through paint
- - Using a cheap roller - invest in a medium-pile microfibre roller for emulsion
- - Applying paint too thickly - it sags, drips and takes forever to dry
- - Painting in direct sunlight - the paint dries too fast and leaves streaks
- - Removing masking tape after the paint has fully dried - it peels the paint off with it
- - Skipping primer on new plaster - the plaster absorbs the paint unevenly
When to Call a Professional
If walls have significant damp issues, major cracks that keep reopening (which may indicate structural movement), or if you need to deal with artex removal or lead paint, call a professional decorator or plasterer.