The question is regularly asked whether it is possible to cover existing old tiles or paving slabs. The short answer is yes, it can! There can be more, but let's follow a few rules.
Very often we lay the new one on top of the existing old pavement. In addition to the time and work that can be saved, we protect ourselves from a lot of dirt and scum, and we know that time is also money, not to mention the costs of removing the significant amount of scum and dismantling the old coverings. If you have to carry a lot of shit to a container, for example, from upstairs, we can easily imagine the additional disadvantages of this.
This way, we can save several thousand HUF on each square meter. In the case of a larger surface, this can be a significant amount.
Rules of thumb
The base must be properly flat and load-bearing, moving damaged parts must be picked up. The old covering can be checked quickly by knocking, if you hear a clicking sound while knocking, then the surface is not suitable, as the old covering no longer sticks to the wall or the subfloor. Such defective sheets or tiles must be removed and filled in their place. In the best case, it affects at most a few sheets and there is nothing to prevent the re-covering of the entire surface.
The tile adhesive does not adhere to the surface of the existing ceramic covering, so a special adhesive bridge must be used. After dusting and degreasing, the suction bridge can be easily applied by rolling or with a brush. Think of it as a liquid glue that contains coarse particles. It bonds perfectly to the old covering and its grainy surface makes it receptive to tile adhesive.
What else should we pay attention to?
Let's calculate that covering the existing covering will increase the thickness of the covering by the thickness of the covering material, as well as the thickness of the necessary adhesive bed, i.e. it may be necessary to cut off the bottom of the doors or replace the existing threshold if it is not high enough.
The depth of the existing water outlets and connector boxes is also such an important factor, as they will all be deeper with the new cover. Fortunately, splicing fittings are easily available, so they do not cause any particular problems.
However, the situation is not so simple in the case of a tub with a covered front wall, which typically needs to be dismantled, since the plane of the tile is designed for the rim of the tub, for this it is usually necessary to remove the old tile on the front wall of the tub. However, there is no need to worry, this only produces a bag of shit for us, which we can typically drop off for free as residential construction waste.
Choose a high-quality flexible tile adhesive. It is not worth saving money on this, because on the one hand, it is not a significant cost compared to the total cost, and on the other hand, it is all the more important that we do not have problems with our new covering for a long time.
Laying a new covering on the old tiles or paving slabs
From there, everything works just like tiling on a smooth subfloor or wall. The grouting can also be done in the usual way and we saved a lot in the process!