Taken from The Tile Association
The maximum weight of tiling which can be supported by a dry, well-adhered plaster background is 20kg/m². This is equivalent to ceramic tiles with a maximum thickness of 8mm plus tile adhesive or natural stone tiles with a maximum thickness of 7mm plus tile adhesive
The weight of tiling to a plasterboard background direct (without plaster skim) should not exceed 32kg/m². This is equivalent to a ceramic tile and adhesive with a maximum thickness of 12.5mm and natural stone and adhesive with a maximum thickness of 10mm.
It is important to emphasise that the weights quoted includes both the tile and adhesive.
Further advice should be sought either from the manufacturer, regarding the suitability of the adhesives and grouts and also guidance must be sought from board manufacturer regarding additional information on recommended methods for the installation of boards.
The following table offers general guidance to some common types of building board and the maximum recommended weights for tiling.
Wall SubstratesMaximum Weight of Tiling per m² Gypsum Plaster 20Kg/m² Gypsum Plasterboard Direct (without a plaster skim) 32Kg/m² Plywood (WBP) Up to 30Kg/m² Lightweight Tilebacking Boards* Up to 40Kg/m². Dependant upon the type and thickness of the board. Glass reinforced Cement Sheets Up to 50kg/m², Dependant upon the type and thickness of the board. Gypsum Fibre boards Approximately 35- 40Kg/m²