Step 1 Excavation
If conduit or wires are located in the area to be excavated, contact the representatives of the company concerned before the work is started. To ensure sufficient drainage, excavate the soil to obtain a minimum incline of 2% (20 mm/m or 1/4 inch per foot). The excavation contour should extend beyond the surface to be paved by at least 300 mm (12"). Ideally, this distance should be 1 to 1-1/2 times the thickness of the foundation. The stability of the project depends on this measurement, which ensures that the slabs at the edge will be as well supported as those in the centre. Level the bottom of the excavation with a rake and, if the soil is sandy, compact it with a vibrating plate or roller. It is preferable not to pack clay soil at this stage. In this case, the use of a geotextile membrane placed between the natural soil and the foundation is recommended to prevent foundation contamination by clay and ensure greater.