Tiling onto plaster
Plaster is a very common interior substrate that generally provides a good, flat surface for tiling. There can be, however, certain problems associated with plaster and these need to be overcome with correct preparation and application.
Common issues and queries you can face
Support
Plaster can only support relatively small/light tiles
- Plaster is a relatively weak material (in comparison to wood, brickwork, concrete etc). The maximum weight of tiling which can be supported by a dry, well-adhered plaster background, is 20 kg/m2.
- New plasterwork should have been completed at least 4 weeks prior to tiling commencing. Even if the surface appears to be dry in less than 4 weeks, the layers underneath will not be.
Water-sensitive
Plaster is water-sensitive
Plaster is water sensitive and is therefore not an ideal substrate in areas subject to wetting such as showers or wet rooms.
The finish quality
The finish quality can be very variable
Plaster finishes, when prepared for tiling, should be finished in accordance with the recommendations given.
Very often the finished surface of plaster can be very variable, depending on the conditions and the plasterer. The surface can be very dusty or, if over-trowelled, it can be very dense and shiny.
Reactions with plaster
Cement adhesives react with plaster
When plaster comes into contact with cement it forms a weak layer of ettringite that can cause the adhesive and plaster to not adhere to one another. Careful preparation is needed to stop this happening.