How to Prepare Walls for Wallpaper

Proper wall preparation is the single most important factor in whether your wallpaper looks professional or disappointing. Skipping prep is the most common mistake DIYers make, and it is also the hardest to fix after the fact. Wallpaper adheres to the surface beneath it and conforms to every bump, crack, and imperfection. Invest the time in preparation now and the hanging process will go smoothly — literally.

Assess Your Wall Condition

Before doing anything, take a close look at your walls. Run your hand across the surface and note:

• Is the surface smooth or textured?
• Are there nail holes, dents, or cracks?
• Is there existing wallpaper that needs to come off?
• What type of paint is on the wall (flat, eggshell, semi-gloss)?
• Is there any mould, mildew, or water damage?
• Are there areas of loose or flaking paint?

Each of these conditions requires a different treatment. Let us go through them one by one.

Removing Old Wallpaper

If there is existing wallpaper on the wall, it must come off. Never hang new wallpaper over old wallpaper. The moisture from fresh paste can reactivate the old adhesive, causing both layers to bubble, wrinkle, and eventually peel away from the wall. Here is the removal process:

1. Test a corner. Try peeling a corner of the old wallpaper. If it comes away easily and cleanly (common with strippable vinyl wallpaper), you may be able to dry-strip the entire surface without chemicals or steam.
2. Score the surface. If the wallpaper does not peel easily, use a wallpaper scoring tool to perforate the surface. This allows the removal solution to penetrate behind the paper.
3. Apply removal solution. Use a commercial wallpaper stripper mixed with warm water according to the label instructions. Apply generously with a sponge or spray bottle and let it soak for 10 to 15 minutes.
4. Scrape. Use a broad wallpaper scraper held at a low angle to lift the paper off the wall. Work from the bottom up. Be careful not to gouge the drywall beneath.
5. Clean residue. After removing the paper, there will be adhesive residue on the wall. Wash the wall with warm water and a sponge, or apply more removal solution. All residue must be removed — leftover adhesive will prevent new paste from bonding properly.

Alternative: steam stripping. A wallpaper steamer is faster for stubborn paper, especially multiple layers. Hold the steam plate against the wall for 20-30 seconds until the paper softens, then scrape. Be careful not to over-steam — too much moisture can damage drywall.

Filling Holes and Cracks

Once you have a bare wall (or if you are starting with bare painted walls), fill every imperfection:

• Nail and screw holes: Fill with lightweight spackling compound using a putty knife. Overfill slightly — the filler shrinks as it dries.
• Small cracks: Open hairline cracks slightly with the corner of a putty knife, then fill with flexible filler or caulk. For cracks that reappear (often around door and window frames), use a fibreglass mesh tape over the crack before filling.
• Large dents or gouges: Apply filler in layers, letting each layer dry before adding the next. A single thick application is more likely to crack and shrink.
• Damaged drywall paper: If the paper face of the drywall is torn or peeling (common after wallpaper removal), seal it with a coat of shellac-based primer (such as Zinsser BIN). This prevents the damaged paper from bubbling when you apply new paste.

Sanding

After all filler is completely dry (follow the product instructions — usually 1-2 hours for lightweight filler), sand the patched areas smooth with 120-grit sandpaper. The goal is a surface that is flush with the surrounding wall. Run your hand over each patch — if you can feel a ridge, keep sanding.

For glossy or semi-gloss painted walls, lightly sand the entire surface with 150-grit sandpaper to create a slight tooth for the primer to grip. You do not need to remove the paint — just scuff the sheen. Wipe away all sanding dust with a damp cloth or tack cloth before proceeding.

Dealing with Textured Walls

Textured walls (orange peel, knockdown, skip trowel, or popcorn) are common in North American homes and are the enemy of wallpaper. The texture prevents adhesive from making full contact with the wall, leading to poor adhesion and a bumpy appearance.

Your options depend on the severity of the texture:

• Light orange peel: You can often skim coat over this with a thin layer of drywall compound, let it dry, and sand smooth. One or two skim coats will create a suitable surface.
• Moderate knockdown: Sand the high points with 80-grit sandpaper to flatten the peaks, then skim coat the entire wall. This typically requires two coats with sanding between them.
• Heavy texture (popcorn): This is the most work. You can wet the texture and scrape it off (if it is unpainted), or apply a thick skim coat. For ceilings with heavy popcorn texture, many people opt not to wallpaper at all.

After skim coating and sanding, the wall should feel as smooth as glass. Remember, wallpaper reveals every imperfection — a flaw you can barely see on a painted wall becomes glaringly obvious under wallpaper.

Cleaning the Walls

Before priming, give the walls a thorough cleaning:

• Wipe down with a damp cloth or sponge to remove dust, cobwebs, and loose particles.
• For kitchen walls, use sugar soap or a degreaser to remove grease films that prevent adhesive from bonding.
• For bathrooms, check for any mildew spots. Treat with a mildew remover (diluted bleach solution works) and let dry completely.
• Let walls dry fully — at least 24 hours after washing — before applying primer.

Priming: The Non-Negotiable Step

Priming is the step that most DIYers skip and most professionals consider essential. A proper wallpaper primer (also called sizing) does three critical things:

1. Seals the wall. Drywall and plaster are porous. Without primer, they absorb moisture from the paste too quickly, weakening the bond and making it difficult to slide strips into position.
2. Creates a consistent surface. Patched areas, bare drywall, and painted sections all absorb paste at different rates. Primer evens this out so every part of the wall behaves the same way.
3. Makes future removal easier. When you eventually want to remove the wallpaper, primer prevents the paste from bonding directly to the drywall paper. Without primer, removal often damages the drywall surface, requiring extensive repair.

Types of Wallpaper Primer

• PVA-based sizing: The most common and affordable option. Diluted PVA (white glue) applied to the wall. Good for most residential applications.
• Acrylic wallpaper primer: A step up from PVA. Creates a stronger seal and works better on previously painted surfaces. Products like Zinsser Shieldz are specifically designed for wallpaper.
• Alkyd/oil-based primer: Best for sealing problem surfaces like smoke-stained walls, water stains, or heavily patched areas. Zinsser Cover Stain or similar products work well but have strong fumes — ventilate the room.

Apply primer with a roller, covering the entire wall in an even coat. Let it dry according to the label — usually 2-4 hours for acrylic, up to 24 hours for oil-based. The wall should feel smooth and slightly tacky to the touch when ready for wallpaper.

Special Situations

New Drywall

Fresh drywall must be fully taped, mudded, and sanded before wallpapering. Apply a coat of drywall primer (PVA primer) first, then a coat of wallpaper-specific primer on top. Two coats of primer are necessary because new drywall is highly absorbent.

Previously Wallpapered Walls

After removing old wallpaper and cleaning all adhesive residue, inspect the wall carefully. The drywall paper surface is often damaged during removal. Seal any torn or fuzzy areas with shellac-based primer before applying wallpaper primer over the entire wall.

Painted Walls in Good Condition

If the existing paint is well-adhered, in good condition, and has an eggshell or satin finish, you can prime directly over it. Flat and matte paints need a coat of wallpaper primer. High-gloss paint should be lightly scuffed with sandpaper first to give the primer something to grip.

Wall Prep Checklist

Before you start hanging, confirm every item on this checklist:

• Old wallpaper removed completely, no adhesive residue remaining
• All holes, cracks, and dents filled and sanded smooth
• Wall surface is clean and free of dust, grease, and mildew
• Textured walls have been skim coated and sanded smooth
• Wallpaper primer applied and fully dried
• Outlet and switch covers removed
• Furniture moved away from the wall and floor protected with drop cloths

If the prep reveals heavy texture, damaged drywall paper, or old paste that will not release cleanly, bring in an installer before ordering the final rolls. For Calgary wall prep and wallpaper installation, connect with Wall Style Innovations - Window Film & Wallpaper so the surface is corrected before the paper goes up.

With your walls properly prepared, you are ready to start hanging. Head to our complete wallpaper hanging guide for the next steps.