The Full Process of Preparing the Substrate for Large-Format Tile: Why 80% of Problems Start Here

Substrate preparation is the foundation of any quality surface of large-format tile, porcelain stoneware or natural stone. At M-STONE (Kyiv, Kyiv region) we have repeatedly faced rework where clients saved on this stage and got cracks, voids and tile coming off after only 6-12 months.

Today we will go through the whole process step by step so that you understand what you are paying for and why professional work is worth its money.

Step 1. Diagnosing the existing substrate Before any work begins, a specialist assesses the condition of the substrate. We check:

• flatness of the surface with a laser level or a 2-metre straightedge (tolerance of no more than 2 mm per 2 m);
• screed strength (minimum M150-M200, better M300);
• cracks, delamination, oil stains, old paint;
• moisture level (not above 2-3% for porcelain stoneware);
• the load-bearing capacity of the floor slab (especially important in old houses in Pechersk, Podil and the Shevchenkivskyi district).

If the substrate “moves” or has height differences of more than 10 mm, dismantling and a new screed are mandatory. Saving here = overpaying 3-5 times later.

Step 2. Dismantling (if required) We remove the old covering with a rotary hammer with SDS-max or diamond cups. In apartments on Khreshchatyk, Velyka Vasylkivska and Saksahanskoho streets we often meet asbestos-containing materials from the 70s and 80s: we dispose of them according to the regulations. We generate a minimum of dust with Karcher industrial vacuum cleaners + HEPA filters.

Step 3. Waterproofing and priming In bathrooms, kitchens, on terraces, balconies and in basements (a frequent case in private houses in Brovary and Obukhiv) we always apply coating waterproofing in 2 layers (Ceresit CR 65, Knauf Flächendicht, Mapei Mapelastic). The overlap onto the walls is 20-30 cm. Then a deep-penetration primer (Ceresit CT 17, Knauf Tiefengrund) in 1-2 layers to reduce absorbency and increase adhesion.

Step 4. Levelling and screed Height differences up to 20 mm: self-levelling floors (Ceresit CN 69, Vetonit 3000, Bergauf Easy). Differences of 20-80 mm: a semi-dry screed with fibre and plasticiser (reinforced with 50×50×3 mm mesh if necessary). For large areas (from 100 m², for example commercial properties in the Dniprovskyi district, shopping centres in Vyshneve) we use mechanised delivery of the mix. Strength gain takes 7-28 days depending on thickness and grade.

Step 5. Final priming before laying 1-2 hours before applying the adhesive: an adhesion primer (concrete contact or quartz) for perfect bonding.

Why is this important precisely for large format? Tile of 120×120, 120×278, 160×320 hardly bends at all. Any unevenness → stress → a crack or void → water → destruction. In Kyiv, with its temperature swings (-20…+35 °C) and humidity, this is especially relevant. At M-STONE we always record every stage on photo/video so that the client sees the transparency.

A real example from practice Site: a cottage in the village of Stoianka (Kyiv region). Height differences up to 45 mm over 120 m². We made a 40 mm semi-dry screed + a 5 mm self-levelling finish. Then we laid 120×278 porcelain stoneware that imitates marble. After 2 years: not a single complaint.

Want your floor/walls/facade to serve for decades without rework? Write to us: [email protected]

See our work and processes: Instagram → @mstone_kiev Facebook → M-STONE Kyiv YouTube → M-Stone Kyiv

Do not take risks with “cheap craftsmen”: write or call today and we will calculate the exact cost for your project in any district of Kyiv or the region!

The current cost of work for your project can be calculated in the online calculators or confirmed by the manager: it depends on the material, the slab format and the condition of the substrate. The consultation is free.