The remains of the old concrete foundation present the same requirements as in the case of the construction of the foundation in rocky soil, except that you can try to play around with the planting of a new building and pile rows between the old foundation.
If it is not possible to move the building along the site, then local excavation or drilling should be carried out at the installation sites of geosharts. After this, you need to fill the resulting voids with sand, with a layer-by-layer compaction with water. Similar installation situations arise when you need to mount the foundation on an asphalt surface. In this case, we make holes in the asphalt to the depth where the soil begins. Only after this starts screwing into the soil layer, and not into asphalt or fragments of bricks, or crushed stone.