After constructing the sump, the next step is digging/excavating for the foundation of the building. This is an important stage as the dimensions of the foundation have to be perfectly right because otherwise, the future spaces will be affected. The foundation depth depends on the soil quality and the design of the foundation is decided by the site conditions. The excavation drawing and foundation details are prepared by the structural designer and approved by the Architect.
MARKING THE EXCAVATION:
Marking: The Contractor has to follow the excavation drawing prepared by the structural designer and approved by the Architect. The excavation plan is marked at site and the dimensions are cross-checked by the Architect. It is advisable that you also check the dimensions as any mistake can be brought to the Architect’s and Contractor’s notice so that it can be rectified before it is late.
DECIDING THE EXCAVATION DEPTH:
Excavation: Once the marking has been approved, the excavation can begin.
Depth of excavation: The excavation depth depends on the soil condition. Digging is done till hard soil is reached. For a fair idea, you can check with the neighbouring buildings, the depth of their excavations.
Filled up soil: If your site/Layout is formed on lakes or low-lying areas, it may have a lot of filled up soil. In such areas excavation must be done till firm ground is reached. Usually the depth of the foundation will be more and consequently the cost of the foundation will be very high. But do not compromise. Make sure the building is resting on solid ground even if it means you have to go 15 feet down, because otherwise it will affect the stability and strength of the house.
Excavation trenches/pits: The excavation details depends on the construction method that you have decided to adopt, the load-bearing-wall system or the column-beam-frame structure system. If it is a load bearing system, then trenches along the walls of the house have to be excavated. If it is a column-beam structure, then footings for columns have to be excavated. In either case, the architect approved, structural engineer’s foundation drawings and details must be followed.
Anti-termite treatment: Before laying the foundation, make sure that the trenches and excavated areas have been given the anti-termite treatment by the Contractor. This will ensure protection against termites and other pests from underground, in the future
