Choosing the correct application thickness is essential for the performance, durability, and appearance of any self-leveling flooring system. Although product instructions always take priority, most systems are designed for specific thickness ranges rather than unlimited application.

For minor surface imperfections, a thin layer of approximately 2–5 mm is often suitable. This range can smooth scratches, small depressions, and uneven transitions before installing vinyl, tile, wood, or other floor coverings. Medium applications of 5–15 mm are commonly used when the substrate has more noticeable irregularities or requires improved flatness.

For deeper repairs, some high-build self-leveling compounds can be applied at 15–50 mm, either in one application or in multiple stages. However, thicker installations may require special formulations, primers, reinforcement, or aggregate. Using a standard thin-layer product beyond its recommended limit can lead to cracking, shrinkage, poor curing, or delamination.

Before application, the substrate must be structurally sound, clean, dry, and free from oil, dust, paint, and loose materials. Moisture testing is also important, especially over concrete slabs. Cracks and expansion joints should be treated according to the manufacturer’s instructions, while the correct primer helps control absorption and improves adhesion.

The required thickness should be determined by measuring the highest and lowest points of the floor. The average thickness must remain within the product’s technical range, and additional material should be allowed for surface texture and local depressions. Temperature, humidity, mixing accuracy, and working time can also affect the final result.

For reliable performance, never select thickness based only on appearance. Follow the technical data sheet, use suitable measuring tools, and install the system under recommended site conditions. Correct thickness, careful preparation, and controlled installation together create a stable, smooth, and long-lasting floor.