Removing Old Tiles Without Damaging the Plaster

Assess the Wall Before You Lift a Single Tile

Before you reach for a chisel, work out what is actually holding those tiles on. Tap along the wall with the handle of a screwdriver. A hollow, tinny sound usually means the tiles are sitting on dry-lined plasterboard, dot-and-dab board, or adhesive that has already failed. A dull, solid thud suggests sand-and-cement render or bonding coat over brickwork, which is far more forgiving to work with.

This matters because plasterboard, especially the 9.5mm stuff used in older bathrooms, will crumble the moment you apply leverage. If the board is soft, stained, or crumbly at the edges, stop trying to save it. Cut it out with a utility knife and a plasterboard saw, right back to the studs, and plan to replace it. You will save yourself hours of patching.

Also check the age of the property. In homes built or refurbished before 2000, some tile adhesives, backing boards and floor tiles contain asbestos. Never dry-sand or break these up. Damp them down, keep dust to a minimum, and arrange a survey if you are unsure. A dust mask, safety glasses and gloves are non-negotiable here, as tile shards are vicious.

Tools That Make the Job Easier

• A wide bolster chisel, around 75mm, rather than a narrow wood chisel. A wide blade spreads the force across more of the wall.
• A club hammer of 1kg to 1.5kg for controlled taps. A claw hammer delivers too sharp a blow.
• A grout rake or oscillating multi-tool with a grout removal blade to cut the joints first.
• A stiff scraper or wallpaper stripper for lifting the last stubborn tiles.
• Old dust sheets, a rubble sack, and a board or tray to protect the bath or shower tray.

Cutting the grout lines before you start is the single biggest favour you can do yourself. Grout locks the tiles together into one rigid sheet. Break those joints and each tile comes away individually, which means far less force transferred into the plaster behind it.

The Bolster Chisel Technique

Start at the edge of the tiling, or at a tile that is already cracked or loose. Work your way inward rather than trying to remove a tile from the middle of a solid field.

Hold the bolster at a shallow angle, roughly 20 to 30 degrees to the wall, with the bevel of the blade facing the plaster. Place the tip into the grout line or behind the tile edge and strike the end of the chisel with light, brisk taps of the club hammer. You are aiming to slide the blade behind the tile and prise it forward, not to smash your way through.

Once the tile lifts a few millimetres, change the angle slightly and work the chisel along the edge. You should hear a soft crackling as the adhesive releases. If you find yourself swinging hard, stop. Either the chisel is too narrow, the angle is too steep, or the adhesive is too well bonded and needs a different approach.

Work downwards and sideways as you go, clearing debris frequently. A pile of broken tiles underfoot is a trip hazard and it stops you getting the chisel flat to the wall.

When the Tiles Fight Back

Cement-based adhesives, common in wet areas, grip like limpet glue. A steam wallpaper stripper held against the tile face for a minute or two can soften the bond just enough to help, particularly with older dispersion adhesives. Do not overdo it near plasterboard, as trapped moisture weakens the paper facing.

For very stubborn tiles, run an oscillating multi-tool with a carbide blade down the adhesive line from the side, then return to the bolster. On larger format porcelain, score the tile face with a grinder before chiselling so it breaks into manageable pieces rather than levering as one heavy slab.

Repairing the Damage Before You Re-board

Some gouges are inevitable. What matters is how you deal with them.

• Shallow scuffs and thin adhesive residue: scrape flat, then sand with a damp sponge and 120-grit paper. Prime and tile over.
• Gouges up to 5mm deep: fill with a two-part repair filler or patching plaster, feathering the edges, then sand flush once cured.
• Deep craters or blown plaster: remove all loose material, apply a bonding coat or hardwall plaster in two passes, then skim. Allow it to dry fully before tiling.
• Holes in plasterboard larger than a fifty-pence piece: cut back to a rectangle and screw in a new patch of board, taped and filled at the joints.

Do not be tempted to fill deep holes with tile adhesive. It shrinks, cracks, and gives you nothing solid to fix to.

Preparing for New Boards or Waterproof Backing

Inside a shower or above a bath, plaster alone is not enough. Once the wall is sound and flat, fit a cement-based tile backer board of 6mm to 12mm, screwed at 200mm centres with the joints taped and sealed. Alternatively, apply a liquid tanking membrane or a waterproof matting system over the prepared plaster, especially in the corners and around the shower valve and pipe penetrations.

Prime the surface with the manufacturer's recommended primer, then use a flexible, cement-based adhesive rated S1 or S2 for any large format or porcelain tiles. Give everything a final check with a spirit level and a straight edge. A flat wall now means a crisp, evenly grouted finish later, and a bathroom that stays watertight for years.