Leveling concrete floors and screeds

Professional laying of carpet flooring, PVC and parquet can only be done on flat, dry and clean surfaces, whose surface is not very absorbent and is not porous. It is especially important, that when gluing floor coverings there is a difference in height between two points by a distance 40 cm did not exceed 1 mm. At the spacing of the surface points of the row 4 m there are still acceptable height differences up to 10 mm.
Concrete floors and cement screeds often have greater height differences. The smoothing and leveling of concrete floors and cement screeds has always been a difficult task, an intense and time-consuming matter. For some time, there have been so-called. “liquid screeds”, which are made with water and poured onto the floor, they self-dissolve and form tight, a pressure-resistant and perfectly flat surface. Liquid screeds are suitable for laying carpet coverings, PVC and parquet (of course also for ceramic floor coverings). They can be applied in layers up to a thickness of 30 mm, they are walkable after less than a day and can be covered with floor coverings after a week or so.

A specialist advises
First, bounce off all protruding mortar residues with a hammer and chisel. Also brittle layers, old paint coats and impregnations should be removed by grinding or brushing. Then the floor should be thoroughly sweep.

Material requirement
• For coverings of height 2 do 10 mm, no additives are added to the mixture.
• At the height of the layers in between 10 a 20 mm to the powder, made with water, grit sand is added 0-4 mm. The mixture ratio is 1 part of the powder on 1 part of the sand (parts by volume).
• For covers up to 30 mm mixed to the powder, fine gravel spread with water (graininess 0-8 mm). The mixture ratio is here 1 part of the volume of powder to 2 parts of the gravel volume.

Before applying a liquid screed, the floor must be primed. Usually, it is sufficient to prime the mortar diluted with water with an improver. Also, the edges of the floor surface must not be forgotten. Before the liquid screed can be applied, the Primer must be completely dry.

A specialist advises
For highly absorbent floors (carry out a wetting test!) it is necessary to apply adhesive sludge. For this purpose, a liquid screed is prepared by mixing water to a spreadable consistency. Slime, applied with an old bench should not form a layer thicker than 2 mm. It needs, depending on the room temperature, to harden and dry 5-10 hours.

First, arrange the hard foam edge strips around the walls. Next, mix the cement-containing powder and the plastic-enhanced powder with water to a pourable consistency. To obtain the correct mixture ratio, the manufacturer's instructions must be strictly adhered to. You need the so-called. basket mixer, resp. vane, which can simply be attached to the drill.

Po 5 maturing for a minute, the screed is shaken again strongly. The consistency of the mixed mixture is then correct, when it slightly melts after being poured on the floor. When water or powder is added, the whole thing has to be thoroughly and thoroughly mixed again.

The mixture is poured in stripes on the floor surface. Start from the side of the room, furthest from the door and work progressively towards the door.

Separating the liquid screed should be slightly assisted with a screed trowel. The processing time of the liquid screed is less than half an hour. It is important for a flat spread, that it is applied and separated wet into wet. After separation, the screed flows on its own “To the level”. Do not walk on it until it is fully cured.