As part of a five-year review of British Standards to reflect changes in the tiling industry – BS 5385 Part 1: 2018 has now been published.

A significant change has been the exclusion of plywood as a backing material for direct fixing of ceramic wall and natural stone tiles.

There has also been amendments to adhesive coverage and grout width recommendations.

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UK head of technical services at BAL and member of The Tile Association (TTA) Technical Committee David Wilson said: “Previously it was recognised in BS5381 Part 1 2009 that tiling direct or plywood was possible, providing this was restricted to small areas and be “installed in such a way that they provide a dimensionally stable and rigid background”.

However, he pointed out cheap plywood was now being imported and the moisture content of wood can also change so its stability cannot be assured.

In addition, David Wilson commented plywood cannot hold the same weight of tile as a tile backing board: “Plywood is deemed to have a maximum weight of tiling per sqm of 30Kg compared to proprietary tile backing boards which generally are capable of supporting heavier weights per sqm of tiling.”

Changes to BS5381 Part 1 2009 also include the coverage of adhesive, driven by an increase in the size and types of tiles. See our tile trend feature Cover up for the latest trends.

Previously, in internal dry wall areas, it was recommended adhesive should cover a minimum of 50% of the back of the tile.

BS 5385 Part 1: 2018 now advises: “Tiles with a surface area of less than 0,1sqm, but which weight more per sqm than 70% of the background’s capacity to carry the weight, should be solidly bedded e.g. the maximum weight of tile that can be supported by Gypsum plaster =20kg; whereas 9mm thick porcelain tiles, which weigh approximately 18kg/sqm, weigh more than 70% of 20kg therefore, they should be solidly bedded regardless of their size.”

In addition, changes have been made in the minimum recommended grout joint width, dependent on tile/panel size.

Joints between ceramic panels should be increased pro-rate to panel size (e.g. for a 3m long ceramic panel, the minimum required joint width is 5mm).

For more information, contact the BAL Technical Advisory Service.