Experience is the greatest adversary when it comes to the installation of natural stone. Poor quality workmanship and preparation are all too often seen in the building industry today.
This section will give you an indication to some of the common problems and faults, all of which can be very easily over come.
Today’s market place is flooded with different types of adhesive, many of them sold at incredibly low prices. Never is the adage ‘You pay for what you get’ so true. A cheap unbranded adhesive will not last as long as a high quality product and will not have as many properties as a premium adhesive so it wont be as flexible, wont have as long an opening time and generally wont stick aswell.
Quality adhesive manufactures such as Ardex spend a great deal of money or research and development to produce adhesives for different tiling situations. These include internal and external use, wet and dry area use, flexible and normal setting.
The biggest problems seen today are normal setting non flexible adhesives being used on wooden substrates or with underfloor heating. This obviously leads to cracked floors and tiles lifting.
A non waterproof internal adhesive being used externally will also just lead to the tiles lifting after a very short time.
You should always follow the manufacturers mixing and fitting instructions, they are there for a reason.
Tiles coming away from the wall or floor with no adhesive stuck to the back of them can be because of a number of reasons; the adhesive was mixed either too wet or too dry, the tiles were wet when they were laid which doesn’t allow the tiles to bond, it was too cold for the adhesive to be effective and the tiler let the adhesive dry too much before the stone was laid.
All too often we see floors with cracks in them after they have just been laid. This is down to a number of factors all of which can be eliminated relatively inexpensively.
Timber floors should always be laid as a minimum of 18mm over-ply or two layers of 12mm cross bonded. With the addition of a movement matting such as Ditra matting you will virtually eliminate the possibility of a cracked floor. Tiling onto a thin sheet of plywood or sometimes MDF will only lead to trouble, and costly repairs.
With sand and cement and screeded floors you should always allow the screed to dry sufficiently before tiling; a typical screeded floor will need at least 6 to 8 weeks to cure before you can tile onto it. The reason you should wait is because as the floor dries it shrinks and this causes cracking. This is visible in a tiled floor when the crack appears to run across the tiles from one to another in near enough a straight line.
Similar problems happen with wall preparation, if the wall is not fixed securely or there is movement in the substrate this will lead to tiles cracking and coming away from the surface. You must always ensure the wall can carry the weight of natural stone as a typical plastered wall can only take the weight of approximately 30 kg/per meter squared.