Check of substrate

The ready floor covering is only as good as the substrate allows. Therefore, check the substrate carefully and prepare it for the installation of the final flooring. The substrate must be dimensionally accurate and technically suitable in order to be able to provide a flawless floor covering on it. Dimensionally accurate means sufficiently level, flush, horizontal or with the planned slope. Technically means load-bearing, clean, dry, dimensionally stable and free of adhesion-impairing particles. The tests described here serve to assess the substrate in order to be able to select a suitable substrate pre-treatment afterwards.

Simple & safe to the goal

The visual inspection

Every substrate inspection should start with a visual inspection of its entire surface. Rough defects can already be detected and a first evaluation of the substrate is made. The further test methods are then determined on this basis.
The dimensional accuracy

The dimensional accuracy of the substrate is checked using aids, such as a folding rule, spirit level, straightedge, string, plumb bob or laser levelling device.
The documentation

All activities must be documented in relation to the building site and the files added to the documentation.
The grid scoring test

1. Using a pointed steel nail or a hardness scoring device, scribe several lines parallel to each other at a distance of approx. 6 mm.
2. Then repeat this procedure at an angle of 40° - 60° on the previously scribed lines so that a diamond pattern is obtained.
3. If the surface hardness is sufficient, the intersection points of the diamond pattern must be neat and without any break-outs.
The tap test

A blunt hammer is used in order to identify cavities in the substrate. If a dark sound is produced when tapping, there may be a cavity. Hollow spots should be repaired by suitable measures.
The hammer blow test

1. The hammer blow test can be used to detect whether peeling and stratification are present in the laying substrate (e.g. screed). A blunt hammer is used to strike the surface at an angle of approx. 45°.
2. If a shell bursts out of the surface, the surface must be freed from the deposits by suitable measures (grinding, milling).
The wipe test

1. Wipe the surface with a dry cloth or by hand. If any residues of dust and loose particles still remain, remove them.
The wetting test

1. The substrate is sprinkled with water. If the water is absorbed very quickly, the substrate is too absorbent. The absorption behaviour can be reduced by using a suitable primer.
2. If the water remains on the substrate, the substrate is weakly absorbent. If the absorption behaviour is optimal, the water is absorbed slowly but continuously.
The moisture measurement

The readiness of the substrate for covering depends on its residual moisture. For its measurement, we recommend using a carbide hygrometer. The instructions for use of the respective device manufacturer must be observed.
The tensile strength of surface

The traction force (pull-off strength) is measured without drilling by pulling a metal disc bonded on the prepared concrete or screed substrate. Paste-like adhesives without a consolidating effect are to be used. Solvent-free adhesives must be used, if the substrate is covered with polymer-modified weber.floor levelling compounds. PMMA adhesives are not suitable.
The tensile strength between layers

For testing the adhesion of layers to each other, pre-drill in an appropriate diameter. We recommend using solvent-free, paste-like epoxy resins, such as the quick-curing EP primer weber.floor 4715.