Can I plasterboard over a tiled wall?

Taking tiles off a wall usually takes the plaster with it, which turns a decorating job into a re-plastering job. Boarding over them avoids all of that, keeps the mess to almost nothing, and gives a fresh flat surface. The catch is entirely about fixings: plasterboard has to be held by something, and glazed tile bedded on adhesive is not something.

What you'll need

• Plasterboard
• Long screws and frame fixings, or drywall screws for studwork
• A tile bit or a multi-material bit
• Stud, cable and pipe detector
• Tape and jointing compound
• Timber battens (optional)

Step by step

1. Tap the tiles first and find out whether they are sound.Hollow tiles are already debonded. Boarding over a wall of loose tiles gives you a new surface hanging on old adhesive that is letting go, and it will move. Loose tiles come off.
2. Establish what is behind the tiles.Studwork, masonry, or dry lining. This decides everything about the fixing. Drill a test hole through a tile in an inconspicuous place with a tile bit and see what the dust says.
3. Check for damp before you cover anything.Tiles in a bathroom or kitchen frequently hide a wall that has been getting wet behind a failed seal. Boarding over it seals the moisture in with new paper-faced board on top.
4. Choose the fixing route.Into studs: long drywall screws through tile and board into the timber, pre-drilling the tile with a tile bit to stop it cracking. Into masonry: long frame fixings or plug-and-screw through everything into the brick or block. Onto nothing: batten out first.
5. Batten out where you cannot reach anything solid.Fix vertical battens through the tiles into the masonry or the studs at 400 or 600mm centres, packing them to a flat plane, then board onto the battens. This also gives you a service void and a flat wall independent of the tiles.
6. Pre-drill every fixing point through the tile.A sharp tile or multi-material bit, no hammer action, slow speed, and a piece of tape over the spot to stop the bit wandering. Hammering a screw straight through a glazed tile shatters it and loses the fixing.
7. Plan for the thickness.Tiles plus adhesive plus board plus finish is a substantial build-up — often 30mm or more from the original plaster line. Sockets, pipes, a basin, a bath edge, a window reveal and a door architrave all have to be considered before you commit.
8. Tape and finish, or skim.As with any boarded wall. Use moisture-resistant board in a bathroom or kitchen, and tile backer board rather than plasterboard anywhere that will be tiled again or that gets wet.

Common mistakes

• Fixing plasterboard into tile adhesive — There is nothing there to hold a screw. The board is being held by friction and paper, and it will move, crack at the joints and fail.
• Boarding over tiles in a shower area — Standard plasterboard has no business behind or near a wet area. Tile backer board fixed to a sound, dry substrate is the correct build-up.
• Not checking the door and window details first — Thirty millimetres of build-up leaves a door architrave sunk into the wall and a window reveal with a step in it.

Alternatives

• Remove the tiles and re-plaster: The thorough answer. Expect the plaster to come off with them and budget for re-plastering. Right where the tiles are loose, where the wall is damp, or where you cannot afford the lost dimension.
• Batten and board: Battens fixed through to solid material, board on top. Solves the fixing problem, the flatness problem and the service problem at once, at the cost of more depth.
• Tile over the tiles: Possible on a sound, flat, well-keyed tiled wall with the right adhesive, and much thinner than boarding. It stacks weight on an old adhesive bond, so it is limited by what is underneath.
• Skim over the tiles: A plasterer can bond and skim a sound tiled wall. It is thin and quick, and it is entirely dependent on the tiles staying put — a debonded tile takes the skim with it.

Questions people ask