r/DIYUK • u/samjonseh • 1d ago

Is this okay to tile over?

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Gallery image

Removed the old tiles from the bathroom ready to retile and it took a large chunk of the plasterboard with it. Is this okay to retile over, or does the plasterboard need replacing?

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u/Outrageous-Play7616 1d ago

Is this in a wet area beside the bath?

Personally if you are going to the trouble of redoing the tiles then cut it out up to the height of the tiles and replace with 10mm Jacko board or similar tile backerboard.

The problem with using plasterboard in a wet area (even if moisture resistant) is that water will always get behind the tiles as the grout isn’t waterproof, and will turn the board to mush and your tiles fall off.

The other problem is gypsum in the plasterboard reacts with the cement in powder based adhesive when it gets wet. This creates phosphates and then your tiles fall off. The only way to get around this is to prime it with primer G and then tank it using a tanking system.