How to Paint a Wall: Fresh Plaster & Previously Painted Walls
Painting a wall that’s already been painted before seems simple, but the prep makes all the difference. A bit of extra time filling, caulking and sanding will give you a smoother finish, help the new paint grip properly and make the room look freshly done rather than “just rolled over”.
What this guide covers
This guide is for previously painted interior walls in standard emulsion, plus a section for vinyl silk and fresh plaster. It walks through every step from prep to your final coat.
Tools and materials you’ll need
- HB42 (or similar) decorators’ caulk
- Toupret Fill-Flex flexible filler
- Toupret Interior Filler or TX110 Quick Dry
- Filler knife and Hamilton Precision Scraper
- Pole sander + P60–P80 sheets
- 2.5" Oldfields brush for cutting in
- 12" Hamilton roller sleeve
- Dust sheets and masking tape
- Trade-quality matt emulsion
- Hoover/brush and a damp cloth
HB42 decorators caulk for gaps around skirting and frames.
2.5" Oldfields brush – ideal for cutting in walls and ceilings.
12" Hamilton roller sleeve for a smooth, even finish.
Step 1 – Protect the room and check the walls
Move furniture away from the walls and cover everything with dust sheets. Mask switches, sockets and woodwork. Look along the walls in good light and mark any cracks, digs or gaps.
Step 2 – Caulk gaps between wall and woodwork
Before filling walls, deal with gaps between walls and skirting, frames and architraves. HB42 caulk is ideal because it tools off cleanly and holds its shape.
- Run a smooth bead along the gap.
- Lightly smooth with a damp finger or profiling tool.
- Remove excess so no ridges dry on the edge.
HB42 is smooth, flexible and takes paint well.
Step 3 – Rake out and fill cracks properly
Use a scraper to gently rake out cracks. You’re not enlarging them — just giving filler something to grip.
A sharp scraper makes raking cracks easier and cleaner.
For deeper cracks, use Toupret Fill-Flex. Push it firmly into the crack and scrape it level. Avoid leaving it proud — flexible fillers can be harder to sand back.
Toupret Fill-Flex is ideal for cracks that move or flex slightly.
Once dry, skim over with Toupret Interior Filler or TX110 Quick Dry to level the surface. Do this at the same time as filling digs and old screw holes.
Avoid ready-mix fillers. They often sink, dry soft and can flash under paint. Powder fillers mixed fresh always give a better, longer-lasting repair.
Toupret Interior Filler – reliable all-round powder filler.
TX110 Quick Dry – ready to sand and paint in a few hours.
Step 4 – Sand the filler and the whole wall
When filler is completely dry, sand it flat. Then sand the entire wall using a pole sander with P60–P80 grit.
A pole sander helps flatten filler and key the whole wall quickly.
This levels old roller texture and gives new paint something to grip. Hoover dust and wipe walls before painting.
Step 5 – Cut in the edges
Cut in before rolling. A good 2.5" cutting-in brush is small enough for awkward areas but big enough to make progress.
The 2.5" size is perfect for straight lines and neat edges.
Step 6 – Roll the paint on
After cutting in, roll the walls quickly so everything blends while still wet.
- Use a decent 12" roller sleeve.
- Work in sections, top to bottom.
- Overlap into cut-in areas so no band is left around the edge.
A good roller sleeve gives you an even finish with fewer marks.
Step 7 – Apply the second coat
Let the first coat dry fully, then repeat the same process: cut in, then roll. A properly prepped wall with two coats should look even with no flashing.
Painting fresh plaster (including mist coats)
Fresh plaster needs a slightly different approach because it’s very porous. The key is a proper mist coat — not PVA.
1. Ensure the plaster is fully dry
It should be a light, uniform pink with no dark patches. Painting too early can trap moisture and cause peeling later.
2. Never use PVA
PVA creates a shiny, non-porous film that stops paint adhering. It can cause your finish to peel off in sheets. Always use a mist coat instead.
3. Mix the mist coat properly
A good ratio is:
- 70% paint, 30% clean water
Use basic matt emulsion — not vinyl matt, vinyl silk or durable matt.
4. Apply the mist coat
Roll it on evenly. Don’t aim for opacity; the point is simply to seal the plaster.
5. Lightly sand once dry
Fresh plaster often has small nibs or trowel marks. A light sand with P120–P180 smooths everything ready for top coats.
6. Apply two full coats
Cut in first, then roll. Two decent coats should give a smooth, even finish.
Extra tip for new builds
New-build plaster is often rough or uneven. A pole sand before the mist coat will dramatically improve the final finish. Hairline cracks may appear later as the building settles — these can be filled with flexible filler and touched up.
Special case – Painting over vinyl silk walls
Vinyl silk is shiny and can react badly with new paint if not prepped correctly.
Do not use PVA. It can cause bubbling. Instead, give the wall a thorough sand (power sander helps) to remove the sheen, then paint two coats as normal.
When it’s worth calling a decorator
If walls are heavily cracked, uneven, water-damaged or full of repairs, it can be more cost-effective to get a decorator in. Most of the work is in the prep — not the rolling.
If you’re in or around Basingstoke and would like it taken care of for you, I’m always happy to provide a free quote for interior painting and decorating.