Can I Install Tile Over a Plaster Wall?

Flat Surface

• The surface of a plaster wall must be flat and well secured to the wall before it can be tiled over. Any holes, dents or cracks in the surface of the plaster should be covered over or filled in before the wall is tiled. You can use joint compound to fill in these imperfections, and then sand down the surface once the compound is set, to ensure a flat wall that is ready for tiling.

Adhesion

• To ensure good adhesion of the tiles, a clean, dry plaster wall surface is required. Any emulsion paint on the plaster must be stripped before tiling can begin because it will react with the adhesive and break down. Gloss paint does not react like this and can therefore be left on the plaster if it is in good condition. If the plaster is bare gypsum, paint it with primer before tiling.

Weight

• Plaster walls can support up to 4 pounds per square foot (20 kilograms per square meter). For a standard ceramic tile, this is the equivalent of tiles up to 0.31 inches (8 millimeters) thick. For stone tiles, which are heavier, a plaster wall can only support tiles up to 0.28 inches (7 millimeters) thick. These maximums allow for the additional weight on the plaster caused by the grouting and tile adhesive.

Considerations

• Tiling should only be attempted on a fully dried and cured plaster wall. Otherwise, bowing and adhesive failure will occur. New plasterwork should be left for four weeks to fully dry before tiling, rather that just being dry on the surface. The latter is often the case when a dehumidifier has been used for quick drying.