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Preparation – Testing The Substrate

Before starting a tiling job, testing the substrate is crucial in order to avoid claims and to guarantee a long-lasting result. For this purpose, the areas are inspected visually and, if necessary, subjected to a mechanical and chemical test. This includes important steps like measurement of moisture (floor), checking substrate conditions, grinding the surface (CSA) and priming.

Basically, the surface must fulfil the following conditions: it must be sufficiently load-bearing, dry, even and free of dust and grease.

Moisture measurement

Evaluating the residual moisture in the substrate (floor) is in the responsibility of the tiler before starting with any tiling system installation - the CM method is a profen guideline for testing whether the substrate is dry enough and ready for tiling.

Ceresit Tiling Systems LP, Moisture measurement, size 1280x960

Checking substrate conditions

Checking substrate conditions (evenness, rigid, sandy, holes).

Visual Inspection

Ceresit Tiling Systems LP, Visual inspection, size 1280x960

A visual check of the subfloor can indicate any visible surface imperfections like cracks, efflorescence, moisture damage, etc.

Scratch Test

Ceresit Tiling Systems LP, Scratch test, size 1280x960

The surface is scratched crosswise using a sharp metal object, e.g., a screwdriver, knife, or nail. The deeper the scratch, the lower the strength or bearing capacity of the subfloor.

Wetting Test

Ceresit Tiling Systems LP, wetting test, size 1280x960

The wetting test provides information on the absorbency of the subfloor. If the water is absorbed and the surface turns dark, it is necessary to apply a special primer for absorbent subfloors.

Adhesive Tape Test

Ceresit Tiling Systems LP, adhesive tape test, size 1280x960

A strip of adhesive tape is pressed down on an old paint coat. If the coat comes off when removing the tape with a sharp pull, it must be removed. Afterward, a strengthening primer must be applied.

Wipe Test

Ceresit Tiling Systems LP, wipe test, size 1280x960

A wipe test is performed with the hand or a dry sponge, especially on plaster surfaces. If the hand or the sponge is covered with a chalk layer after wiping the wall, the chalking surface must either be consolidated or needs to be replaced entirely.

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