The 1×1 of tile adhesives: Types & Overview of use

The right tile adhesive is one of the most important criteria for an optimal result when tiling. Unfortunately, it is not always easy to find it among the countless products. That’s why good advice is needed – and that’s exactly what this article is supposed to offer you.

What is the important thing with tile adhesive?

Laying tiles is not exactly the easiest thing to do. In order to achieve the desired quality, you need not only manual skill and the utmost care in preparation and execution, but above all the right material. And this applies not only to the tile itself, but also to the tile adhesive.

But this is also the key point that challenges even experienced craftsmen when making purchases. At first glance, tile adhesives appear to be almost indistinguishable. And also their actual function, i.e. to glue tiles, is basically fulfilled by all of them. However, you should not choose a product arbitrarily. Ultimately, the decisive factor is for which tiles, on which substrates and in which application areas the respective adhesive is suitable. And when it comes to these factors, not every product is the same.

What types of tile adhesives are available?

Basically, a distinction is made between cement-based and non-cement-based tile adhesives, although within these two categories there are different variants:

Cementitious tile adhesives

Cement adhesives are the most commonly used today for laying tiles. Although the term “adhesive” is actually not quite accurate in this case. In truth, these are not so much tile adhesives in the literal sense of the word as mortars.

The products usually consist of a cement-sand base and various additives and are available as dry mixtures in bags or buckets. To become ready for use, the powder only needs to be mixed with water to form a lump-free mortar mass. The adhesive effect results from hydraulic curing. This means that by adding water, the cement becomes solid and thus ensures the necessary adhesion of the tile.

But beware: This setting process is relatively fast, which is why it is necessary to process it as quickly as possible. You should therefore not mix too much tile adhesive at once, otherwise it will not be possible to apply it. Completely dry and thus resilient, the adhesive is usually after about 24 hours, the product contains special accelerators, the time span is even shorter.

Cement adhesives are very useful for laying on the wall as well as on the floor. In principle, they can be used on all rigid, absorbent surfaces, such as concrete, screed or plaster. In addition, they are water-resistant and frost-proof and are therefore also suitable for tiles in outdoor areas without further ado.

Flexible adhesive

The so-called flex adhesives offer even more application possibilities indoors and outdoors. They also belong to the cement-based tile adhesives, but become a real all-round genius thanks to special plastic additives.

Firstly, the plastic component allows the material to cure more flexibly. This enables flex adhesive to better compensate for vibrations, tensions and movements in the substrate and thus prevents cracks or chipping in the tile. This is particularly advantageous when laying tiles on subfloors such as dry screeds, fibre cement, plasterboard and wooden floors, but also for tiles on underfloor heating systems.

Secondly, the plastic provides a significantly higher adhesive strength than is the case with conventional cement adhesives. This means that flexible mortar not only ensures a secure hold on difficult or particularly smooth surfaces (e.g. tiles on tiles), but also when laying tiles with a very dense or glassy surface, such as porcelain stoneware or mosaics.

But all these advantageous properties have their price, of course. Flex adhesives are generally much more expensive than standard tile adhesives.

Natural stone adhesive

Since conventional cement adhesive is not suitable for natural stone, there are special natural stone adhesives for this purpose. Although these products also contain cement, they bind the water particularly quickly. This prevents the cement from settling via the water in the sensitive and porous surface and causing discoloration. In addition, the adhesive is usually white or transparent, which does not affect the appearance of the natural stone tiles.

Fluid bed adhesive

When laying tiles on large floor areas, special cement adhesives are also frequently used: the so-called fluidised bed adhesives. Their consistency can be flexibly varied between more or less liquid, depending on the amount of water added, so that they are – as the name suggests – suitable for fluid beds. This means that they do not have to be applied to each tile separately like the otherwise much more viscous standard tile adhesives, but can be spread directly on the floor. Since the back of the tiles is completely wetted with adhesive with this laying method, cavities under the tiles can be excluded. That is why fluidised bed adhesives not only provide optimum adhesion for large-format tiles, but are also ideal for outdoor applications. This is because cavities can quickly lead to frost damage, especially in these areas.

Non-cement-based tile adhesives

As this article is about an overview of the different types of tile adhesives, the repertoire of course also includes non-cement-based adhesives. However, this is more for the sake of completeness, as in practice these play a rather minor role.

Dispersion adhesive

Dispersion adhesives are water-soluble tile adhesives based on plastics, which are usually already available as ready-to-use mixtures. The biggest advantage of these adhesives is that they are more flexible after curing and have a higher adhesive strength than cement mortar. For this reason, dispersion adhesives are also mostly used on smooth surfaces (e.g. plasterboard or rigid foam).

On the other hand, there are also significant disadvantages: dispersion adhesives are not frost-resistant and are therefore only suitable for indoor use. And even there there are certain restrictions: Dispersions do not harden by setting like cement, but by drying, which makes the process much longer. For wall tiles this does not play a major role in principle, but dispersion adhesives are less recommended for the laying of floor tiles for this reason.

Reaction resin adhesive

Reaction resin adhesives can be useful primarily in commercial areas where particularly high demands are placed on the tile adhesive (e.g. commercial kitchens, laboratories, industry, etc.). Due to their excellent adhesive performance and high flexibility, they are not only suitable for critical substrates such as plastic, metal or glass, but are also resistant to chemicals.

However, reaction resin adhesives are hardly to be found in the private sector. Not least because of their complex processing: they consist of two components (synthetic resin and hardener), which must be joined together before a chemical reaction can finally ensure curing.

When buying tile adhesive, the following applies: Pay attention to the brand

Once the question of the appropriate type of tile adhesive has been clarified, it is “only” a matter of selecting the specific product. It definitely does not fail because of the selection. Because no matter whether in the DIY store or in the online shop – products are available in abundance.

The recommendation here is quite clear: quality before price. Or to put it another way: If you want to play it safe, you can also rely on branded products from well-known manufacturers, such as

  • Ardex
  • CMI
  • Knob
  • Lugato
  • MEM
  • PCI
  • Sopro
  • U. v. m.

These probably cost a little more than private labels or no-name products. But for the price you will certainly also get products made from higher quality raw materials, which usually meet all the necessary quality criteria according to DIN EN 2004. Many brand manufacturers also offer their customers a free service hotline for questions and support before or during installation.

Speaking of embarrassing: One final word of advice.

Which tooth size for which tiles?

Whereas tiles used to be fixed to walls or floors with a good portion of mortar, this is now usually done using the thin-bed method. The tile adhesive is applied over the entire surface using a toothed trowel. The size of the teeth depends on the tile format and also has an effect on the tile adhesive requirement. The exact recommendations can be found in the manufacturer’s specifications, whereby the following applies as a general guideline:

Tile edge length up to 100 mm: 6 mm tooth size

Tile edge length 100 to 200 mm: 8 mm tooth size

Tile edge length 200 to 300 mm: 10 mm tooth size

Tile edge length from 300 mm: 12 mm tooth size

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