How to Prepare and Paint Interior Walls
Preparing interior walls correctly is essential for achieving a smooth, long-lasting paint finish.
This guide explains how to prepare walls for painting, when to paint, and how to apply interior wall paint for even coverage and durable results.
Key steps: clean → repair → sand → prime if needed → apply two thin coats.
On this page:
Why preparation matters before painting walls
Interior wall paint will only perform as well as the surface beneath it.
Poor preparation can lead to:
- Uneven coverage
- Visible marks and blemishes
- Poor adhesion
- Reduced durability
Taking time to prepare walls properly ensures the paint bonds correctly and the finish lasts.
What tools and materials do you need?
Before starting, gather:
- Interior wall paint
- Paint roller and tray
- Paint brush (for edges and cutting in)
- Sandpaper or sanding block
- Filler and filling knife
- Dust sheet
- Sugar soap or mild detergent
- Clean cloth or sponge
Having everything ready helps avoid rushed or uneven application.
How to prepare interior walls for painting
Clean the walls
Walls should be free from dust, grease and dirt.
- Use sugar soap or a mild detergent
- Rinse with clean water
- Allow walls to dry fully
This helps the paint adhere evenly.
Cut in edges first
Use a brush to paint:
- Corners
- Edges
- Around sockets and switches
This ensures clean edges before rolling.
Sand the surface
Light sanding:
- Removes rough patches
- Creates a key for the paint
- Helps achieve a smooth finish
Wipe down walls after sanding to remove dust.
Prime if needed
Priming is recommended if:
- Walls are newly plastered
- Surfaces are very porous
- You are painting over dark colours
Primer helps seal the surface and improves paint coverage.
When is the best time to paint interior walls?
Interior walls should be painted when:
- The room is dry and well ventilated
- Temperatures are moderate (not too cold or humid)
- Walls are completely dry after cleaning or filling
Good conditions help paint dry evenly and reduce marks.
How to paint interior walls properly
Cut in edges first
Use a brush to paint:
- Corners
- Edges
- Around sockets and switches
This ensures clean edges before rolling.
Apply paint with a roller
- Load the roller evenly
- Apply paint in smooth, overlapping strokes
- Work in sections to maintain a wet edge
Avoid overloading the roller to prevent drips and streaks.
Apply additional coats if needed
Most interior wall paints require:
- Two coats for full coverage
Allow the first coat to dry fully before applying the second.
How to maintain painted interior walls
To keep walls looking good:
- Allow paint to cure fully before cleaning
- Use a soft cloth or sponge
- Avoid harsh cleaning products
Proper maintenance helps extend the life of painted walls.
Frequently Asked Questions
Interior walls should be cleaned, repaired, lightly sanded and primed if necessary before painting.
Priming is recommended for new plaster, porous surfaces or major colour changes.
Walls should be completely dry after cleaning or filling, typically 12–24 hours depending on conditions.
Cut in edges first, then apply paint evenly with a roller using smooth, overlapping strokes.
Most interior wall paints require two coats for even colour and coverage.