Why can the floor in a new house subside? Reasons and solutions!

Type of work: soil base stabilization under the concrete floor slab, filling voids beneath the slab, restoring slab-to-soil contact, partial lifting and leveling of the floor slab.

• Implementation of work: June 2025

The house was built in 2020:
− a custom-designed single-story residential house with a complex layout; overall dimensions: 16.33 m x 17.76 m; includes terraces;
− foundations: reinforced concrete piers.

During a visual inspection of the house, company specialists identified floor slab settlement in two rooms. After conducting a full inspection (audit), the specialists concluded that the soil layers beneath the first-floor slab had compacted during the building’s operation and under additional load, which led to voids and uneven floor settlement. The soil beneath the floor slab was found to be uneven, insufficiently compacted, and unstable. According to geodetic survey data, floor level deviations from the conditionally accepted mark of 0.000 ranged from +1 mm to -16 mm.

Based on technical documentation provided by the client, the visual inspection, and the dynamic probing report (soil density), specialists developed a project-based technical solution.

The following works were carried out by the specialists:
− soil base stabilization under the concrete floor slab to a depth of up to -3.8 m from the slab surface;
− filling voids beneath the floor slab and restoring contact between the slab and the ground;
− partial lifting and leveling of the floor slab (eliminating cracks and gaps between the slab and supporting walls).

The entire project was completed in 4 days. The customer received a 10-year guarantee for the work.