How to prepare a room for painting: the pro prep checklist
Great paint jobs are won before the tin is opened. Follow these steps and your walls look smooth, the colour looks even, and the paint lasts for years.
⚡ The short version
Painters often say prep is most of the job. It is true. Filling, sanding and priming take longer than the painting itself, and they are what makes the finish look professional. Skip them and every crack and nail hole shows straight through the new colour.
✅ Your prep checklist
Tick each step as you go. Your ticks are saved on this device, so you can come back to it tomorrow.
🪜 Step by step, the way pros do it
Clear the room and protect the floor
Move furniture to the middle and cover it. Lay cotton dust sheets on the floor, as plastic gets slippery. Take down curtains, pictures and shelves. Unscrew switch and socket covers, or tape over them.
Wash the walls
Paint does not stick well to grease, dust or nicotine. Wash walls with sugar soap and warm water, then rinse with clean water. Kitchens and hallways need this most. Let the walls dry fully.
Fill holes and cracks
Use a flexible filler for nail holes, dents and hairline cracks. Overfill slightly, as filler shrinks a little as it dries. For deep holes, fill in two layers. Use decorator’s caulk on gaps between skirting and walls, and around door frames.
Sand smooth and dust off
Sand the dried filler flush with the wall using fine sandpaper. Give glossy woodwork a light sand so the new paint grips. Then vacuum and wipe everything with a damp cloth. Dust is the number one cause of a rough finish.
Seal stains and prime bare spots
Water marks, smoke stains and felt-tip will bleed through emulsion. Seal them with a stain-blocking primer first. Spot-prime filled patches and bare wood so they do not show as dull patches under the top coat.
Mask the edges
Use good painter’s tape on glass, light switches and anything you cannot remove. Press the edge down firmly. Remove the tape while the last coat is still slightly soft for a clean line.
Paint in the right order
Ceiling first, then walls, then woodwork last. Cut in the edges with a brush, then roll the middle while the edges are still wet. Two coats almost always look better than one thick one.
Not sure which paint to buy? Our guide to matt, eggshell, satin and gloss explains which finish to use in each room.
⚠️ Old paint and lead: read this first in older London homes
Many London homes are Victorian, Edwardian or 1930s. Lead was used in some household paints until the 1960s, especially on doors, windows, skirting and railings. It is still found under newer layers in older homes.
If lead is found, it is often safest to paint over sound paint rather than remove it. When removal is needed, it should be done with wet methods and proper dust control. The HSE guidance on lead and the Painting and Decorating Association have more advice.
We work in period homes every week, from Chelsea and South Kensington to Hammersmith and Fulham, and we check old paintwork before we start.
🧱 Painting new plaster
Fresh plaster is very thirsty. If you paint it with normal emulsion, the paint dries too fast, sits on the surface and can peel. Here is how to do it right:
- Wait until it is fully dry. New plaster changes from dark brown to an even light pink. This usually takes a few weeks, depending on thickness, heating and air flow.
- Apply a mist coat. This is a watered-down matt emulsion that soaks into the plaster and seals it. Check the tin for the right mix, as it varies by brand. Avoid vinyl or silk paints for this coat.
- Let it dry, then two top coats. Leave the mist coat to dry fully, lightly sand any bits, then apply your two finishing coats.
⏱️ How long does prep take?
| Room condition | Typical prep | What it involves |
|---|---|---|
| Good walls, same colour | 1 to 2 hours | Light wash, a few nail holes, quick sand |
| Normal lived-in room | Half a day | Washing, filling cracks and holes, caulking, spot priming |
| Tired room or big colour change | A full day | Lots of filling, sanding woodwork, stain sealing, extra coat |
| Period home with old paint | 1 to 2 days | Lead check, careful repairs to old plaster and sash windows |
Want to see what a full job costs? Read how much it costs to paint a room in London. Our painting and decorating team always includes this prep in the quote, so there are no surprises.
🔑 Moving out? Prep for your deposit
Nail holes, screw holes, Blu Tack marks and tape on the walls are usually not seen as normal wear and tear. They are a common reason for deposit deductions. The good news: they are quick to fix if you do it before the inventory check.
🔨 What to fix
Fill and sand nail and screw holes. Remove sticky marks gently. Touch up scuffs in the same paint and sheen, or paint the whole wall from corner to corner so there are no patches.
🧽 Then clean
Once the repairs are done, book an end of tenancy clean. Our partner Time4Cleaning cleans London homes for move-out, so your landlord sees a fresh home.
Need a hand? Our home handyman service fills holes, touches up walls and fixes small things in one visit. For businesses, our office handyman team prepares and paints offices out of hours.
❓ Prep questions
Do I need to wash walls before painting?
Yes, especially in kitchens, hallways and bathrooms. Sugar soap and warm water remove grease and dust so the paint sticks. Rinse and let the wall dry fully.
Do I need primer before painting walls?
Not over sound, clean emulsion in a similar colour. You do need it on bare plaster, filled patches, bare wood and stains that could bleed through.
How long should filler dry before painting?
Follow the time on the tub. Small holes are often ready to sand within hours, deep fills can take longer. Paint too soon and the patch can shrink or show through.
How long should new plaster dry before painting?
Usually a few weeks, until it is an even light pink with no dark patches. Then apply a mist coat before your top coats.
Is it safe to sand old paint?
Not if the home is older and the paint may contain lead. Test it first and never dry-sand or burn off paint that could contain lead.
What order should I paint a room in?
Ceiling first, then walls, then woodwork such as skirting, doors and window frames.
Rather skip the prep? We’ll do it all
Send us a photo of the room. We prepare, paint and clean up, and you get a clear, free quote.