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The right tile adhesive for your project

Correct processing of the adhesive is extremely important so that you can enjoy your tiled surfaces for a long time. We'll tell you how it works. And: glue is not just glue! Here you can find out what types there are and what they are used for.

More on the subject:

Tile glue? Cement glue? Mortar? What do you use to lay tiles? The craft jargon sometimes leaves you at a loss, but luckily you don't need much to get a perspective:

When talking about tile adhesives, in most cases nothing other than mortar is meant. The cement adhesive is mixed on the construction site from the dry mortar mixture (contains cement) and water or other additives. It is also the most commonly used tile adhesive. In addition to the mortar, there is a large selection of different adhesives, we have an overview for you:

What types of tile adhesives are there?

Without tile adhesive, there would be no tiled floor or tile mirror, of course. But not every adhesive is the same, neither in terms of material nor in terms of use. A distinction is made as follows:

  • Cement adhesive / cementitious thin-bed mortar: As already mentioned, it is the most common of all adhesives and ideal for absorbent concrete, screed or plaster substrates. Cement glue is frost-proof and water-resistant and is therefore also suitable for outdoor areas. After adding water, cement glue sets quickly, so it has to be processed quickly. It is then hardened after 24 hours. The processing usually takes place in the thin bed process (layer thickness: 1-4 mm) and sometimes also in the medium bed process (5-15 mm). The latter is often used when laying large-format tiles, because the level of the flooring can be corrected even more after the tiles have been placed.
  • Cement adhesive for natural stone / natural stone thin-bed mortar: Because normal cement adhesive can discolour natural stone and marble if improperly processed, there are special cement mortars for this purpose. One reason for the possible discoloration is the porosity of natural stone slabs, through which components of the cement mortar can become visible on the surface. We therefore recommend the use of natural stone thin-bed mortars, which are characterized by high and rapid crystalline water binding. As an alternative to natural stone tile adhesive, it is often sufficient to cover the back of the natural stone slab with a thin layer of adhesive before it is placed in the combed mortar bed. If translucent natural stones such as onyx or alabaster are being laid, a white natural stone adhesive mortar is recommended.
  • Flexible adhesive: Also an adhesive of the cement tile mortar type, but more expensive and with plastic additives, which among other things ensure that it is less rigid than pure cement adhesive after drying. For this reason, flexible adhesive can absorb vibrations, tension and other movements of the tile substrate better - this prevents the tiles from flaking or tearing. This property is advantageous in the case of dry screed elements or fiber cement and plasterboard panels. Due to the plastic additives mentioned, the flexible adhesive is also suitable for slightly critical substrates that require a high level of adhesive force, such as B. old ceramic coverings or other smooth surfaces.
  • Fluid bed adhesive:Fluid bed adhesives can also be counted among the cement-bound tile mortars. They are mostly used for large floor areas and distributed over a large area in order to then press the tiles into this fluidized bed. The advantage here: cavities below the coverings are reliably avoided, while the back of the tiles can be fully wetted. This is important, for example, with regard to the adhesion of large-format panels or to avoid frost damage outdoors. The consistency of fluid bed adhesives is also variable, depending on how much water is added. Normal cement adhesives are different: They are much more pasty and therefore not fluid bed capable.

Plastic-based tile adhesive: pros and cons

In addition to the cement-based tile adhesives, there are also those with plastic. You will now find out what they are used for and what advantages and disadvantages they have in comparison.

  • Dispersion glue: These adhesives are not cement-bound, but are water-soluble, plastic-based adhesives that can be bought ready-mixed and ready-to-use. Dispersions are plastics finely distributed in water, which are more flexible when hardened and stick more strongly than cement mortar. That is why they are mainly used on smooth wall surfaces such as plasterboard and rigid foam boards. The disadvantages: The plastic adhesives do not harden through cement binding, as with cement adhesives, but through drying - that takes significantly longer. For this reason, although they can be used for walls, they are unsuitable for floor tiling. Also important: Since dispersion adhesives are not frost-resistant, they can only be used indoors.
  • Reaction resin adhesive: This synthetic resin adhesive based on polyurethane or epoxy resin is mainly used in the commercial sector (large kitchens, laboratories, food industry), especially on difficult surfaces such as plastics, glass or metal, but also wood and chipboard. It consists of two components: the synthetic resin and a hardener, which still have to be mixed on the construction site. Thanks to a chemical reaction, the adhesive hardens later. Not only does it have an excellent bond, it is also very flexible and resistant to chemicals.

Eco tip:

Casein tile adhesive is often referred to as natural tile adhesive because it is based on water as a solvent and the natural product casein (but is also available with natural latex) as a binding agent. However, it is mainly used as an ecological adhesive for bonding wooden elements.

Which tile adhesive is now the right one?

This question depends on the substrate and the area of ​​application. The harder the substrate, the lower the requirements for the tile adhesive. You can use non-slip and frost-resistant cement tile adhesive on concrete surfaces or cement screed with almost no compensation (added synthetic resins). If the proportion of plastic in the adhesive is increased, the tile adhesive also adheres to the smooth surfaces of porcelain stoneware and becomes more flexible at the same time.

Lay new tiles on old adhesive

When laying new tiles on old tile adhesive, it is essential to determine the type and ingredients and to use new tile adhesive of the same type (cement on cement, resin on resin, flexible adhesive made of flexible adhesive, casein on casein, etc.). Why should one pay attention to this? As described for the tile adhesive types, cement adhesives, for example, set hydraulically, while reaction resin adhesives set chemically. The combination of both properties leads to destabilization or even to peeling and breaking of the tiles.

Danger! It is generally not advisable to apply new tile adhesive to old tile adhesive. However, if an old tile adhesive is still in good shape and forms a relatively flat surface, there is little objection to direct application.

Get to work: mix the tile adhesive

The commercially available tile adhesives are mixed with water, the manufacturer's instructions must be observed. First fill a bucket with the specified amount of water and then mix in the tile adhesive (attention: not the other way around!). Then mix vigorously with a paddle mixer and let rest for around five minutes. After stirring again, the tile adhesive is ready for use. When determining the amount, it is important to consider the open time of the adhesive. This is the time between mixing and skin formation. The adhesive then begins to harden and is no longer suitable for processing. The open time is usually between 20 and 40 minutes. To lay one square meter of tiles, you need two to three kilograms of tile adhesive.

Apply tile adhesive

The so-called thin-bed method is now the most frequently used technique when it comes to attaching tiles to walls or floors using mortar. Gone are the days when tiles were attached to their destination with thick lumps of mortar. Today one applies full-surface adhesive layers and not just punctual lumps. Flexible tile adhesives make it possible.

Before you start, make sure you are equipped with the right tools for tiling. Start gluing on the most facing side of the installation surface. Think about which edge cut tiles do not interfere and start applying the adhesive there. Apply the adhesive to the wall with a trowel and comb through it with a notched trowel. Make sure that you always hold the notched trowel at the same angle, otherwise the thickness of the adhesive will change. Once the adhesive has been distributed over the entire surface, peel off the surface horizontally with the notched trowel.

Tip:

Tile adhesives were reinforced with asbestos fibers until the mid-1980s. Ideally, have a toxin analysis carried out before renovating old bathrooms or kitchens!

How to remove any tile adhesive

To remove tile adhesive, you should know what type of adhesive you are dealing with. The subsurface allows conclusions to be drawn as to which adhesive was used to lay the floor. Frequently used Dispersion adhesive adhere very strongly, so it is no easy task to get these adhesives off walls. If the use of the spatula does not have any effect, the adhesive can be tackled with a paint stripper and dispersion remover (which now uses biological agents). The last glue residue is rubbed off with cooking oil. At Synthetic resin adhesives you have to use harder guns for better or worse: hammer and chisel, (electric) scraper and stripper are suitable depending on the strength and size of the surfaces. Remnants are brushed in with an adhesive solvent and then wiped or troweled off. Removing Thin bed mortar requires mechanical help. An electric chisel is used for the rough preparatory work, a concrete grinder for the rest. Caution: The subsurface will inevitably suffer from this concentrated impact force. Therefore, after removing the tile adhesive, it is usually necessary to fill in the potholes and depressions. Leveling compound can also be used on the floor.

Another tip: even if you replace a single tile, you have to remove the old tile adhesive. Using a hammer and chisel can damage adjacent tiles. An oscillating tool like a multimaster simplifies such work.