At the end of November 2020, a request was received. In a residential building, the floor slab had settled due to damage to a sewer pipe. For two years, wastewater had been washing out the sandy foundation beneath the reinforced concrete floor slab in the kitchen area of 30 sq. m. As a result, the floor slab had settled by an average of 3 cm.

Causes:
During the survey, a team of specialists identified loosening of the foundation soils to a depth of 0.7 meters relative to the top of the floor slab, and voids were also detected beneath the floor slab. The work was complicated by the presence of a two‑circuit water‑heated floor in the slab.

The design engineer, together with the work supervisor and the project manager, developed a technical solution to eliminate the identified deficiencies.

In February 2021, a team of specialists carried out work to strengthen the foundation soils to a thickness of 0.7 meters and to level the floor slab back to its original position with an accuracy of ±1 mm. The work was carried out through the basement part of the monolithic foundation. Upon completion of the work, the customer received level floors without mechanical damage, a dense foundation, an undamaged heated floor, and a 5‑year warranty on the performed work.