How to Prep Your Wall for Wallpaper
How to get a wall solid, clean, dry, flat and dust-free, including what to do about old wallpaper, new plaster, painted walls and anything textured
A wall is ready for wallpaper when it is solid underfoot, clean, dry, flat, free of dust and an even neutral colour. Getting it there means clearing the room, taking off anything loose, filling and sanding, washing down, sealing where the surface is porous, and letting everything dry properly before you open a roll.
Almost every wallpapering problem, from lifting seams to bubbles to paper that will not stick at all, begins on the wall rather than on the paper. This is the least interesting day of the job and the one that decides how the finished wall looks.
What a wall needs to be
- Solid. No loose plaster, flaking paint or crumbling filler.
- Clean and free of grease. Particularly in kitchens and above radiators.
- Dry. Right through, not just on the surface.
- Flat. Filled, sanded and smooth. Any bump under the paper will show once the light crosses it.
- Dust-free. Paste will not stick to dust, and sanding makes a great deal of it.
- Evenly coloured. A dark or patchy wall can shadow through a pale design.
What you'll need
- Dust sheets and masking tape
- Filler and a filling knife
- Sanding block or pole sander, medium and fine paper
- Sugar soap or a mild detergent, a bucket and clean cloths
- Screwdriver for socket and switch faceplates
- Emulsion for sealing bare plaster, or a wallpaper primer
- Wallpaper stripper, scoring tool or steamer, if there is old paper to come off
Step 1: Clear and protect the room
- Move the furniture out, or into the middle of the room and cover it.
- Lift or cover the flooring and tape dust sheets along the skirting.
- Take down pictures, shelves, curtain poles and anything else fixed to the wall you are papering.
- Turn the power off at the consumer unit before you loosen any socket or switch faceplate, and keep it off while you are working with water near them.
Step 2: Deal with what's already on the wall
You can hang new paper over old only if the existing paper is flat, smooth, non-vinyl and completely firmly stuck down. Test it by lifting a corner at the skirting and along a seam. If anything gives, it all comes off.
Take the old paper off if it is any of the following:
- Vinyl or coated, because new paste will not bond to it
- Textured, embossed or woodchip, because the texture telegraphs straight through
- Dark or strongly patterned, because it can shadow through a pale design
- Lifting, bubbled or peeling anywhere
- More than one layer thick
The reason to be strict about this is simple. The moisture in fresh paste soaks through and reactivates the old adhesive, and both layers come away together, usually two days after you finish.
Old paint
Scrape back anything flaking, then feather the edges with abrasive paper so the repair does not show as a ridge. Matt emulsion is a good surface to paper over once it is clean. Silk, soft sheen and eggshell need keying, so sand the surface lightly all over to take the shine off, or the paste has nothing to grip.
If the paint rubs off on a finger, the surface is chalky and unstable. Wash it back as far as it will come, then seal with a mist coat of matt emulsion and let it dry.
Textured coatings
Artex, textured emulsion and heavy relief coatings have to be made flat before anything is hung on them. There is no wallpaper that hides texture, and it reads through the paper as soon as the light is low. Skimming is the reliable answer, and it is a job for a plasterer.
Textured coatings applied before the year 2000 may contain asbestos. Do not sand or dry-scrape an unknown coating. Have it tested first, and skim over the top rather than removing it.
Step 3: Fill and sand
- Rake out any cracks slightly so the filler has something to hold on to.
- Fill holes, cracks and old fixing points, slightly proud of the surface.
- Let the filler dry fully. Deep fills often need a second pass as the first sinks.
- Sand flush with medium paper, then finish with fine.
- Run your hand over the whole wall with your eyes closed. You will feel what you cannot see.
Step 4: Wash the wall down
Wash the wall with sugar soap or a mild detergent solution, working from the bottom up so the runs do not streak dry wall. Pay particular attention to kitchens, above radiators, and anywhere hands touch the wall.
Rinse with clean water, then let the wall dry completely. Papering onto a wall that is still damp traps the moisture behind the paper.
Step 5: Seal, if the surface needs it
What you do here depends on what you are papering onto.
- Previously painted and in good order: nothing needed beyond washing, sanding any sheen, and dusting off.
- New plaster: it must be completely dry first, usually several weeks, and longer in winter or on a solid wall. Then seal it with a mist coat of watered-down emulsion or a proprietary wallpaper primer.
- New plasterboard: fill and sand the joints, then seal the whole surface. Bare plasterboard paper bonds so well to wallpaper paste that removing the paper later can tear the board.
- Previously papered, now stripped: wash off every trace of old adhesive first, let it dry, then seal if the surface is chalky or patchy.
Sealing stops a porous wall drinking the paste out of the paper, and it means the paper can be stripped later without pulling the plaster face off with it. Avoid sealing with neat PVA, which dries to a glossy film that paste struggles to bond to and can soften again when it meets wet adhesive.
Step 6: Think about the colour underneath
A strong wall colour underneath a pale paper will show, not as an obvious block but as a shadow that makes the paper look grubby in daylight. If the wall is dark or bold, paint it out to a neutral base first and let that dry.
The reverse trick is worth knowing for dark colourways. Painting a narrow stripe of a close-matching emulsion down the wall where each seam will fall means that if a seam moves a hair's breadth as it dries, you see a dark line rather than a white one.
Step 7: Let new paint cure
Freshly painted walls need thirty days before you paper over them. Paint is dry to the touch within hours and still curing for weeks, and paper hung too early can lift the paint film off the wall when it shrinks.
This applies whether you have painted the whole wall, painted out a dark colour, or just touched in a filled patch.
Step 8: Dust it off
The last job before you start hanging. Take a clean, dry cloth or a soft brush over the entire wall, including the top of the skirting and the ceiling line. Sanding dust is invisible on a pale wall and it is one of the most common reasons paper does not stick.
Preparing a wall for peel and stick wallpaper
Our removable paper asks more of the wall than the pasted papers do, because it has nothing but its own adhesive to hold on with.
It needs a smooth, firmly bonded, painted wall that is completely clean, dry and dust-free, with the paint fully cured for at least thirty days. It will not hold reliably on:
- Textured or embossed surfaces of any kind
- Bare plaster or bare plasterboard
- Freshly painted walls
- Chalky, powdery or flaking paint
- Rooms that get steamy, and we do not recommend it for bathrooms
If your wall does not meet that description, choose the traditional or heavy-grade paper instead.
When to stop and fix something else first
Some walls are not a preparation job at all:
- Damp. A tide mark, a musty smell, or paper that has previously lifted in one particular place. Find the cause and fix it. Wallpaper over damp fails, and it hides the problem while it gets worse.
- Mould. Treat it and deal with the ventilation problem behind it before anything goes on the wall.
- Salting. White crystalline deposits on a wall mean salts are still coming through and the wall is not ready.
- Blown plaster. Tap the wall. A hollow sound means the plaster has come away from the substrate and needs cutting out.
Can you wallpaper over painted walls?
Yes, and most people do. Wash the wall, sand back any sheen so the paste has a key, fill and sand any damage, dust it off, and make sure the paint has cured for thirty days if it is new.
Do I need to remove old wallpaper before hanging new?
Usually yes. You can paper over it only when the old paper is flat, smooth, non-vinyl and firmly stuck throughout. Anything textured, coated, dark, doubled up or lifting must come off.
How long should I leave new plaster before wallpapering?
Until it is completely dry, commonly several weeks, and longer for a solid wall or in a cold month. It should be a consistent pale colour with no darker patches. Then seal it before papering.
Do I need to seal or size the wall?
On bare plaster or plasterboard, yes, with a mist coat or a wallpaper primer. On a painted wall in good order, no.
Can I wallpaper over Artex or a textured wall?
Not until it has been made flat. Texture reads through wallpaper. Skimming is the reliable fix, and peel and stick will not hold on texture at all.
How long does wall preparation take?
For a painted room in good order, half a day of work plus drying time. For a room that needs stripping, filling and sealing, allow a full weekend, most of which is waiting.
