There is an entire industry based on tile adhesives, and it's large and it's competitive.
On the market today, there are dozens of tile adhesive types which differ from each other depending on the application at hand. For each one of these, there will be a different recipe, different mix ratios, and a different quality of ingredients. We shall examine how such an industry should come to exist, when traditionally sand and cement performed the exact same task, and at a much lower price.
Tile Adhesive vs Sand and Cement
For centuries, tiles and natural stone would have been installed using a basic mixture of sand, cement, and water. However while more expensive, today’s purpose made adhesives come with many advantages.
Because sand which has been quarried for use in regular mortar is not graded for specific use as a tile adhesive, it’s often much too coarse for a perfect mix. This makes it especially difficult to work with on walls, whereas tile adhesive is formulated using fine grain sand of a specified calibre.
When installing something delicate, such as a thin mosaic, what is required is a nice, even shallow bed of adhesive. This makes it less likely to ooze up through the joints when the sheets are applied, especially when a proper notched tiling trowel has been used. A rough, grainy mix of adhesive would make this job extremely tricky, if not impossible.
Furthermore, while building sand has been washed, there usually remain traces of dirt and debris. This can cause a problem when tiling something very absorbent, such as natural limestone, as the dirt can be drawn through the tile by osmosis and cause staining which is visible from the surface.
Similarly, when grouting with a white or light ivory colour, it’s important that the grout does not absorb any dirt or become tainted by the substance used to attach the tile or stone to the substrate. For this reason white tile adhesive is usually used for fixing wall tiles, as it’s more often than not subsequently grouted in a light colour. Using a grey mortar, with possible contaminants, is liable to cause unsightly discolouration to either the porous natural stone or the grouting itself.
It’s easy to handle bags of tile adhesive. Everything that’s required is premixed in the correct ratios and packed in a bag that is easily managed. The quantity required per square metre is known in advance, so it’s not difficult to gauge how much is needed for any particular area – the rest can be left in the bag until needed. The powder is light and easy to work with, and generally does not create a mess.
When working with sand and cement, you’re already dealing with two products from the beginning. Bags of ordinary Portland Cement are usually large, but may only be required for 20% of the mix. It's often the case that a lot of cement would be left over at the end of the job, and then the opened bag would have to be dealt with. Bags of sand are not very portable after opening. The process of mixing sand and cement is time consuming, and dusty, and often needs to be done in a separate location.
But crucially, it’s often the case that tiles would be left to soak in water overnight, especially with the more permeable red body ones. This is done to saturate the tile prior to installation, so that the moisture in a sand and cement mix would not be “sucked up” into the tile, weakening the bond. It’s easy to see how much labour is saved by choosing tile adhesive over a sand and cement mix. Just take them out of the box, and lay them.
The above paragraphs and photo don't give a full grasp of the amount of labour involved in setting out a base using raw materials. Just take a glance at the video below for a better understanding of the effort and experience required to prepare a floor for tiling in the absence of adhesive.
As mentioned earlier, there is a multitude of different types of adhesive, each of which have been created with a specific application in mind. They all contain different quantities of certain ingredients, additives, and polymers, depending on the required situation. This means there is really no limit to the range of surfaces which can be tiled over.
This is not the case with sand and cement. There can be bonding issues in the following cases:
- Fitting tiles with a low absorbency, such as porcelain
- Fitting glass tiles, especially onto very smooth substrates
- Tiling over old tiles
- Installing tiles on surfaces that are liable to move or flex, such as wooden floors
- Tiling onto polished concrete
Aside from the handiness of tile adhesive, far less needs to be used. A sand and cement mix is often applied to substrate, and then another dollop spread on the back of the tile. Too thin, and there will be no bonding at all to either the tile or the substrate. With adhesive, a notched trowel is used, which saves a lot of material waste.
Also, because the mortar mix dries quickly, extra water is often needed during the process, which can weaken the bonding strength. This problem is avoided with tile adhesive due to the use of additives.
By and large, there's always a better bonding strength when tile adhesive is used. And because of the amount of water used with mortar (all now trapped under the tiles which had already been saturated) it’s not possible to apply the grout for a number of days as all the moisture needs time to evaporate. When using tile adhesive, it’s always possible to grout the next day.
Photo Credit: Botament Systems