Jason Brunt, UK Ceramic Product Manager at Mapei UK
Over the last 20 years we have seen a surge in porcelain tile manufacturing and sales in the UK market. Traditional terracotta, followed by biscuit-backed glazed tiles, as well as natural stone, have all shown little growth due to the popularity of the hard wearing porcelain tile.
Trends in the UK have not only moved forward with the type of materials we like to use to decorate our surroundings. Today, size appears to be everything. In technology, the smaller the product the better, is the polar opposite to what customers are choosing for wall and floor tiles. We appear to no longer be content with a 300 by 300mm tile which was the largest tile available not that long ago; your typical tile is now 600 by 600mm. The size of these materials at a thickness of 10-12mm leads to a material which is extremely hard wearing and aesthetically pleasing however due to its density can also be extremely heavy.
While the tile manufacturers have been making efforts to make tiles larger and more hard wearing, in construction and design we are trying to make the substrates lighter weight and unfortunately less stable. We have moved away from the block, brick and render construction methods particularly in regard to our domestic housing. Instead we have metal or timber frame constructions which are more at risk for differential movements than traditional materials.
Considerations have to be made to substrate limitations when choosing the finishing type and size of material. With the “bigger the better” attitude, manufacturers of porcelain materials are looking to push boundaries, and with continuous manufacturing processes are now able to produce some of the largest porcelain tile slabs we have ever seen on the market: we are looking at slabs in excess of 3,200 by 1,600mm in size. Producing these materials at a thickness of 10 to 12mm can be done but the practicality of installing such a material for use in a domestic or small scale commercial environment is impossible, therefore limiting use to specialist installers in large scale commercial installations.
Rather than missing out on this huge domestic market, manufacturers of porcelain tiles have worked on reducing the thickness of the materials whilst not diluting the quality and longevity of the tile. This has been a difficult task to overcome but with tiles reaching 8 on the MOHS scale we now have material harder than steel but as light in weight as practically possible.
The specification of the lighter weight materials still falls under the BS 5385 parts 1-5. Under BS 5385 parts one and two, the size of materials are identified. Tiles exceeding 600mm in length or a surface area greater 1800mm should carefully be considered if tiling internally over the 1st floor height, and in external areas from the ground up.. In some circumstances the material should be specified with mechanical fastening as well as cementitious adhesive fixing. When specifying the tile, the location and background must be considered. Advice from the tile manufacturer or supplier should be sought in these cases. For standard internal installations the normal adhesive practices can be followed and advice from the tile and adhesive manufacturers can be sought.
Although slim porcelain can be as little as 6mm in thickness to ensure the quality of material, the tile is compacted to a point where the water absorption rate is reduced. This process combined with firing at approximately 1200ºC ensures that the finished product has a water absorption rate of less than 0.5%. At a thickness of 6mm these large format slim porcelain tiles are suitable for installation on both wall and floor. Some manufactures have reduced the thickness down to 3 to 4mm and have applied a mesh backing to support the tile, with these tiles popular for facings on areas such as vanity units; when done correctly this gives the unit the appearance of looking like a single piece of stone when in actual fact it is a lightweight prefabricated unit.
Over recent times we have seen large advances in technology used to produce porcelain tiles, leading to products becoming thinner in nature with a wider variety of finishes. With high definition technology, pixelated surfaces on stone-effect porcelain are a thing of the past, meaning a reluctance to purchase these type of tiles is in decline. The easy care and maintenance of porcelain tiles in comparison to a natural stone material, has led to a surge in imitation materials being purchased. Not only have we seen a stone effect, but now the wood effect tiles are starting to gain momentum. Some of the finishes of these materials are so realistic that unless you look at the back of the tile it is impossible to tell the difference from simply looking at the surface.
When choosing a tile of the large format light weight type an adhesive to match in its ability to perform whilst also being light weight itself is an obvious choice. Over the years Mapei has invested heavily in the research and development of adhesive materials, making huge advances in reducing the weight of adhesive products, formulating Ultralite adhesive.
The main reason for specifying thin porcelain may well be in the engineering design with a requirement to reduce the imposing load on a building’s structure. Although the volume of adhesive used to install the materials is small, the overall weight can be crucial in the design.
Based on these calculations, using lightweight adhesives can save this project 10,000kg. Lightweight adhesives can also be used with standard tiles.
Lightweight tile adhesives have been produced for some time by different manufactures, unfortunately there is still a lot of confusion and misunderstanding around light weight products. As with all specifications the price of the product is considered but often not paramount in the decision making process. When the project gets to the sub-contractor however the price of the material is the main factor to be considered. Unfortunately due to the lack of understanding of the materials involved, the price per bag (or price per kilogram) of a light weight adhesive is looked at first. If we use the Mapei Ultralite range as an example.
The consumer or contractor sees the product on the shelf weighing in at 15kg; its standard counterpart alongside in a 20kg bag is cheaper so the obvious thing is to pay less and get more. With Ultralite products, the simplest way to illustrate this is using the analogy, of what weighs more, a ton of feathers or a ton of lead? Even though they obviously weigh the same, the volume of the feathers is far greater than the volume of lead. Although Mapei Ultralite products weigh less, they produce more, yielding up to 60% more coverage in comparison to the same weight of standard materials. Pleasingly, the price does not necessarily inflate by 60% to get this. General workings for costing would be on a price per kilo rate however in this case we must look at the price per meter to see how the consumer makes the savings.
Mapei has developed Ultralite materials for a range of reasons; we reduce our carbon footprint, are able to use recyclable materials, and there are positive effects for health and safety and manual handling in the manufacture of this new product. The development and popularity of slim porcelain along with methods of construction for substrates that these materials are being fixed to, is another reason for the development of this line. As many consumers use slim porcelain for the benefit of a light-weight tile, the use of a lightweight adhesive (such as a product from the Mapei Ultralite range) will obviously add to the benefits.
When developing light weight tile adhesives we look at different raw materials which can replace the normal sand. These can be recycled glass bead or rubber crumb which are lighter in weight and therefore reduce the final weight of material. The manual lifting of 20kg bags also means that one bag should be carried at any one time. Many times on site we see a contactor carrying two bags on one shoulder up a flight of stairs. This can put a large amount of strain on the spine and is unevenly balanced. If a handle is included on a 15kg bag, it is safer and easier to carry two 15kg bags up the stairs and leads to an even balance as one bag can be carried per hand.
The handling of the slim porcelain, particularly a tile measuring 3 metres in length, would be enough for most but when the reverse of the tiles is spread with adhesive the tile may become unmanageable. With a light weight adhesive the overall weight of the back buttered tile is reduced, making it an easier task for the installer.
As required by industry standards a tile greater than 600 by 600mm should be back buttered. This means that not only do we spread the adhesive on the substrate but also the reverse of the tile, thus ensuring that as much contact between the tile, adhesive and substrate is achieved. Spreading the adhesive on the rear of the tile with the flat edge of the trowel before notch trowelling, the adhesive is able to contact fully leading to an excellent bond.
There are many systems available on the market these day to help in achieving the perfect flat finish to the tiling whether the tiles are installed on the wall or on the floor. These self-levelling systems work well with the slim porcelain and when used at regular intervals along the tile face help to achieve that flat smooth finish.
Due to the size of the porcelain tiles being fitted there are obviously reductions in the amount of grout joints. Joints between tiles are vital, particularly these days with the way in which we construct our substrates with joints allowing for some limited movement within the installation. The reduction of the joints will obviously put pressure on an installation. Mapei produces the Ultralite range in both and S1 and S2 format as deformability in the adhesive is vital to allow the aforementioned movements.
Although extremely thin these porcelain tiles may also be used on floors. Floors must be as flat as possible before attempting to lay these tiles so a smoothing compound such as Mapei Ultraplan renovation screed should be used to ensure a good start. The inclusion of an anti-fracture membrane such as Mapei Mapeguard or Mapetex would benefit the installation to make further allowances for any stresses placed to the tiles from both wall and floor substrates. Both the Mapeguard (walls and floors) or Mapetex (floors) are light-weight thin materials which at just under or over 1mm in thickness barely influences the height gain in a floor.
So, the future. Lighter weight products are undoubtedly the future for the tiling and construction industry. Mapei is proud to be at the forefront of these developments working in partnership with manufacturers producing these type of materials and the contractors tasked with installing them.
Mapei UK Ltd
Head office, Mapei House Steel Park Road, Halesowen, West Midlands B62 8HD
0121 508 6970
Specification Centre, 6 Great Sutton Street, Clerkenwell, London EC1V 0BX
020 302 9610