Changes to British Standards
Trimline Group address changes to British Standard 5385-1 Wall and Floor Tiling.
As part of the five-year review of British Standards and reflecting changes within the tiling industry – BS 5385 Part 1: 2018 has now been published. It includes several important changes, of which those working in the industry need to be aware:
- Tiling should be carried out by a skilled operative, who has been trained to a level of competence, certified by a recognised authoritative body, such as the TTA
- Tiling direct to plywood is no longer recommended for wall tiling, but a bespoke tiling backer board should be used
- New adhesive coverage requirements for large format tiles
- New minimum grout widths, dependent on the size of tile
These changes are coming in as part of the regular review of the Standard and are designed to reflect product changes and developments within the industry since the publication of BS 5385 Part 1: 2009.
The most significant change made was to exclude the use of plywood as a background material for the direct fixing of ceramic wall and natural stone tiles.
A significant uplift in the use of tile backer boards and a wide variation in quality of plywood available on the market has provided a solid case for the removal of plywood from the British Standards.
Bruce Hazell, owner here at Trimline Group commented: “We are pleased to see these changes to the British Standards, its highly significant.The industry has evolved a lot since we started out in 1980, over 38 years ago.It’s vital that we never overlook the importance of quality workmanship and the use of suitable, certified products, when installing ceramics, porcelains and natural stone.As we all strive for excellence it will help improve customer confidence in the industry.
It’s also noteworthy that the TTA has been mentioned in the new standards, a real credit to the work that they are doing to improve the quality, and ensure that any work carried out, in the industry is adequately policed.
Today’s tile backing board market is a healthy and competitive one, prices are attractive to contractors and tile fixers.We cannot ignore the features and benefits of tile backer board for providing a substrate for tiling that is dimensionally stable, resistant to moisture & thermal movement and more environmentally friendly.Many of the systems that we offer even come with a complete installation warranty, for complete peace of mind.With Trimline you are always backed up with our specialist technical knowledge and a number of key product solutions.”
David Wilson, a member of the TTA Technical Committee remarked that: “Previously it was recognised in BS5385 Part 1: 2009 that tiling direct to plywood was possible, providing this was restricted to small areas and it was installed in such a way that it provided a dimensionally stable and rigid background.The quality of plywood for tiling purposes has decreased significantly with cheaper imports flooding the market.While higher quality external grade plywood is still available – it is significantly more expensive.
It is important to consider though that that wood is a hygroscopic material which means that its moisture content will change dependent upon any changes in the environmental conditions on site. Therefore, the dimensional stability of wood-based boards cannot be assured, there is always a risk to installing ceramic or natural stone tiles onto plywood or other wood-based sheets.”
Weight restrictions was another technical consideration for wall tiling.Plywood is deemed to have a maximum weight of tiling per m² of 30 kg compared to proprietary tile backing boards which generally are capable of supporting heavier weights per m² of tiling (As per table 3 of BS 5385-1: 2018 and the TTA Internal Ceramic Tiling to Sheets and Board Substrates document 2016).
However, while plywood is not recommended as a background for direct wall tiling, it can still be used as a structural board when overlaid with a suitable tile backing board, particularly where installation of mechanical fixings is required e.g. for mesh backed natural stone where it is not possible to remove 75% of the mesh backing.
Other changes to BS standards:
Previously in internal dry wall areas it was recommended that tile adhesive should cover a minimum of 50% coverage spread evenly over the back of the tile. However, driven by necessity, with the increase in the size and types of tiles i.e. larger formats and thin ceramic panels, now available of the market, BS 5385-1: 2018 advises:
Tiles with a surface area of less than 0.1 m², but which weigh more per square metre 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 = 20 kg; whereas 9 mm thick porcelain tiles, which weigh approximately 18 kg/m², weigh more than 70% of 20 kg (14 kg) therefore, they should be solidly bedded regardless of their size.
Included within the scope of BS 5385-1: 2018 are large format ceramic tiles, ceramic panels i.e. tiles with a surface area >1m² (any edge length >1200 mm) and thin tiles i.e. ceramic tiles and panels with a panel thickness of ≤ 5.5 mm. To reflect this, additional changes have also been made in the minimum recommended grout joint width, dependent on the tile/panel size, e.g. the minimum grout widths vary by tile facial area – an example as follows:
For tiles with a facial area of less than 0.1m² with no side > 600mm long, a minimum joint width of 2mm is required. Tiles with a facial area 0.1m² to 1m² with no side>1200mm long, a minimum joint width of 3 mm is required.
Joints between ceramic panels should be increased pro-rata to panel size (e.g. for a 3m long ceramic panels the minimum required joint width between these panels is 5mm.
Not included in the scope of BS 5385-1: 2018 are Natural Stone Slabs i.e. stone which is more than 12mm thick, Agglomerate stone, Metal, plastic resin, mirror or glass tiles of a similar construction.For these products it is recommended to always refer to the manufacturer of these products for further advice.
“The new Standard contains a number of important changes which everybody needs to be aware of, affecting both product usage and the quality of installation,” says Brian Newell. “The TTA is therefore planning to organise technical seminars in the coming months at which all these changes will be fully presented and discussed. More information on these events will be available in due course.”
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