Levelling compound paves the way for a beautiful new floor. Literally in the truest sense of the word. This is because it serves to level out unevenness in the substrate simply and reliably. Why this is so important, especially when laying on tiles, what different levelling compounds are available and how to proceed best when levelling, we will tell you in this article.
Levelling tiles – what for?
Even if tiles are considered to be extremely durable, sooner or later the moment will probably come when a new covering is needed. Be it because the floor (or even the wall) has become unsightly over the course of time, shows signs of damage or because the tiles simply no longer please.
One option is then to remove the tiles. However, it is far less complicated to simply install the new covering over the old tiles. This is possible in any case, because in principle almost all coverings can be laid on tiles. However, what is generally true for laying floors is especially true in this case: For a flawless result, you need an optimally prepared substrate. This means that the surface must not only be clean, dry and load-bearing, but also, and above all, level. At this point at the latest, the balancing mass comes into play. This is because it ensures the necessary level surface.
With tiles, unevenness is usually pre-programmed by the deeper lying joints alone. In addition, there are sometimes striking structures or patterns on the tiles that can become apparent when laying thinner, flexible coverings (e.g. carpet, PVC, vinyl, etc.). Moreover, the uneven areas increase the risk of cracks or other damage – even supposedly strong materials such as parquet, laminate or a new layer of tiles are not immune to this. Equalizing compound can eliminate all these potential problems in just one step.
What purpose does equalizing mass (still) serve?
But of course, levelling compounds are not only used for tiles. They are generally used wherever there is a need to level out unevenness. This ranges from spot repairs in damaged areas to the levelling of an entire surface – regardless of whether it is indoors or outdoors, whether it is a wall or a floor, and regardless of the material of the substrate. With a possible layer thickness of 30 mm or even more, it is also possible to use levelling compound to increase the floor over the entire surface – for example, to remove barriers or level differences.
What types of balancing mass are there?
In the trade, there is a suitable balancing mass for every application. Depending on the manufacturer and product, they can also be found under designations such as putty, levelling compound or flow filler. Common to all products is that they are dry powders that are mixed with water and applied to the substrate as a liquid mass. There are, however, certain differences with regard to the ingredients and thus the possible applications.
Basically, levelling compounds consist of either cement or gypsum. In addition, certain additives can be added to the material to improve the properties of the levelling compound (e.g. flexibility, faster drying, higher layer thickness, etc.).
Which balancing mass is suitable for what?
Which product is most suitable depends both on the type of use and on the substrate in question. For concrete, cement screeds and most rigid coverings (e.g. tiles), conventional levelling compound is usually sufficient. Even smaller unevenness can usually be repaired without problems. It should be noted, however, that gypsum-containing compounds are not recommended for wet areas (e.g. in showers or bathrooms) or only with additional sealing.
In contrast, some substrates require a little more for the appropriate levelling compound. Wooden floors, dry and heated screeds as well as mastic asphalt, for example, should only be levelled with levelling compound which is flexible due to special additives. If the levelling compound is used under tiles in outdoor areas, it should again be able to level out larger unevenness and also be naturally frost-proof.
In order to be able to select the right product, however, the manufacturer’s specifications of the respective product are decisive in the end in every case. Therefore, these should be strictly observed before every purchase. On the one hand, the packaging contains all the necessary information for the possible areas of application, and on the other hand, precise details about the minimum and maximum height of the compensation mass. How thick the mass must or can be applied is also a decisive criterion. In the interior, for example, it makes a significant difference whether 3 or 20 mm is required for an optimum result if, for example, doors would block due to an excessive compensating mass. While at equalizing mass outside, as mentioned above, higher layers of material should be possible, in order to straighten also larger unevenness.
Apply levelling compound on tiles correctly: Proceed as follows step by step
In order to ensure that in the end the joy of the new covering on the old tiles lasts as long as possible, the greatest care is required. This starts with the preparation of the substrate, continues with the proper application of the material and ends with the correct application of the levelling compound on tiles. The following steps are necessary for this:
In order to ensure the necessary support for the new floor covering, a solid base is required. Therefore, the first step is to check the adhesion of the tiles to the substrate. This is best done by tapping with a rubber mallet. If a tile sounds hollow, it is too loose and needs to be re-glued or removed. Damaged joints should also be scraped out if possible. Any gaps that may arise can already be filled with filler at this point.
2. clean the surface
In the next step, the surface must be thoroughly cleaned. An alkaline cleaner not only removes soiling, but also reliably dissolves greasy deposits and care product residues. In addition, the surface can be roughened with a diamond grinder – but this is usually not absolutely necessary.
3. apply primer
In order for the levelling compound to adhere better to the tiles, a primer or adhesion primer for tiles is strongly recommended. This is simply distributed evenly on the tiles with a roller. It is important that it is a primer for non-absorbent surfaces. Adhesion primers made of expoxy resin or quartz sand are the best choice. It must also be ensured that the primer is completely dry before the levelling compound is applied.
4. mix the levelling compound
When the primer is dry, the levelling compound can be mixed. The exact mixing ratio of powder and water can be found in the description of the respective product and must be strictly observed. Otherwise the mass becomes too liquid, which can affect the quality of the result. It is best to mix with a whisk in one or better several sufficiently large buckets – and continue mixing until the mixture is lump-free and homogeneous.
5. apply insulation strips
In order to avoid sound bridges, insulation strips should be attached to the wall. These ensure that the levelling compound does not flow into the edge joints and that impact sound or other noises can therefore be transmitted directly from the floor to the wall. The insulation strips also help to prevent cracks in the levelling compound.
6. apply levelling compound on tiles
After all these preparations, the equalizing mass is finally applied. As most products are self-balancing, they can be poured directly from the bucket and only need to be slightly directed in the right direction with a spatula or roller. Finally, the soil must be aerated with a spiked roller – or shoes with nail soles.
7. allow the levelling compound to dry
The levelling compound can be walked on after approx. 3 to 4 hours. However, before the new floor covering can be laid, the surface must be completely dry. As a rule, this is the case after about 24 hours, whereby the manufacturer’s specifications are also decisive here.