What architects should know when specifying large-format tiles

by Madelein
What architects should know when specifying large-format tiles

Before architects go ahead and specify large-format tiles, several factors need to be taken into consideration. Why? This will ensure a successful installation and minimise challenges as much as possible.

There will always be unique situations that require unique solutions, but as far as possible, the following should be done to ensure that large-format tiles are installed in the manner that they were intended to. We spoke to two industry experts who shared their insights and invaluable knowledge.

1. Large-format tiles are very unique when it comes to applying adhesives and installation. What do architects need to know in this regard?

Massimo Vassarotti from Avanga Pty Ltd/Iris Group South Africa (MV)
The primary consideration is that the installer is accredited with the supplier and has gone through the proper training.

Ntobela Zamaswazi, ceramics product manager at Mapei (NZ)
Large-format porcelain tiles cover a larger area, require fewer gaps and breaks (grout lines and expansion joints, which are often overlooked) and create the illusion of a monolithic, seamless finish. The larger the tiles, the fewer the number of gaps or breaks in the ceramic covering. For many people, this is considered to be an advantage and is highly appreciated by architects.

2. How do you prevent large-format tiles from falling, slipping off walls or detaching from the surface it was applied to?

MV: Only if a quality adhesive is specified and applied correctly will the slab not detach itself. When it comes to installing slabs on a ceiling (like we are presently doing for a customer), there must be sufficient support to keep the slab attached while the curing process takes place. Plus the installer must be geared for this type of work.

NZ: When installing large-format tiles, the most appropriate adhesive must be chosen in order to ensure they remain perfectly bonded over the years, prevent deformation in the tiles and guarantee the maximum reliability wherever they are installed (on walls or floors, and internally or externally).

Class S1 and S2 adhesives guarantee particularly high levels of adhesion, so that even very large tiles made from porcelain (a material with very low absorbency) may be bonded successfully. Besides the adhesive, grout lines, expansion joints, the double-buttering technique and a correct assessment of site conditions are all fundamental aspects that need to be considered in order to install large-format tiles successfully.

The first step when installing tiles is to make sure the substrate has no cracks and that it is dry, well cured and even, clean and flat.

Tiles must be installed with grout lines at least 2mm wide. The width of the grout lines must be calculated and increased, and where required, according to the surrounding conditions, the area of use, the size of the tiles and the type of substrate.

Grout lines are particularly important when installing large-format tiles because:
• They reduce the effect of out of flatness between the tiles.
• They considerably reduce the modulus of elasticity and, therefore, the rigidity of the tiling: In fact, when tiles are installed and butted against each other, tiling is considered to be practically the same as a continuous, rigid single tile.

Apart from following the layout of structural joints, distribution joints must also be included. When installing tiles on internal surfaces, perimeter deformation joints and distribution joints must be created every 25m². When installing tiles on external surfaces, the surface must be divided into pitch areas of no more than 9-12m².

3. What are the setting times?

NZ: Adhesive setting times vary between two hours, six hours and twelve hours, depending on the type of labour experience working with the large-format tile.

4. What is the cost per square metre?

MV: It all depends on the slab format/size, finish and quality of the supplier. There are a large amount of suppliers now entering the large format market as the trend grows and you get what you pay for with regards to aesthetics and quality. There are no shortcuts in the production lines of large format tiles which require huge investments.

NZ: Installation costs can range between R500 and R900 per square metre.

5. In terms of installation and the whole process, what makes it unique when using large tiles?

MV: The aesthetics and reduction of grout lines give the space a richer feel. Plus the slabs are very versatile, as they can be utilised for floors, walls, cladding (doors, showers, fireplaces, ceilings, facades of buildings), counter tops for kitchens and vanities, interior or exterior.

6. With regards to equipment used, are there any specific equipment that needs to be used for installations?

MV: The equipment is all handheld, which makes the installation very simple once you have the know-how. Large, very expensive machinery is not required, which is a huge cost saving for the customer.

NZ: Movement and handling: Particularly large tiles are usually handled and moved around on site using suction cups and rigid support frames. These all help to stop tiles bending too much, which could lead to them cracking or even breaking. Handling large tiles also requires a proper number of operators.

7. What challenges should architects bear in mind when specifying large-format tiles?

MV: Ensure you align yourself with an established and professional installer/supplier who is able to give full support on projects and quality workmanship. The MAXFINE brand has been in South Africa for 5 years already but the market is still catching up and very new. I would suggest architects utilise the large format slabs appropriately in the creative process. This will allow them to meet clients expectations and give an amazing finished product which they can be proud of.

NZ: The cost of the tiles and cost of installation, including skills and tools, that are mandatory for this type of installation.

8. Any challenges that should be considered? Solutions?

MV: If the installer follows the proper protocol/requirement checks in the installation and application process, there should be no challenges. Therefore gain knowledge and educate oneself prior to the specification process. This can easily be done through presentations and training.

NZ: The substrate to which large-format tiles are bonded, particularly when using thinner tiles, must be perfectly flat. This requirement is applicable for the installation of floor and wall tiles in general, but it becomes even more critical when installing large-format and slim porcelain tiles or stone slabs. If the installation surface is too uneven, it could ruin the appearance of the finished covering or lead to cracking or breaking.

9. When an architect sits down and specifies large-format tiling, what do you think they will pen down?

MV: The only thing that an architect should consider is that the product is not able to bend . . . yet! The rest will be left to the imagination/courage of the architect to move away from old antiquated products and design buildings of tomorrow. Things to look out for are translucent slabs which will completely change the slabs industry once again. (https://www.irisfmg.com/shape-your-ideas/translucence)

NZ: It is critical to have full site details such as area of installation, type of construction material used and substrate of tile installation available.

These insights are critical and should be thoroughly explored by architects when specifying their next project reliant on large-format tiles. Following these steps will undoubtedly result in an aesthetically pleasing and functional end-result.

Acknowledgement and thanks go to Massimo Vassarotti from Avanga/Iris Group South Africa and Ntobela Zamaswazi from Mapei for the information contained in this article.

Main image: Villagres

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