Once the soil conditions, water table level, and climate are determined, the structural engineer will decide on the depth of excavation needed for the foundation. The following are the steps involved in excavation:
a. The top soil is removed and cleared out of the way
b. The corners of the foundation are marked using 2ft long wooden stakes
c. The corners are measured from side to side and corner to corner
d. The boundary is marked using lime lines
e. Decide on a place to dump the excavated earth
f. It is common to dig 2-3ft bigger than the actual size of the home, as this allows you to have space to move around the foundation after it is poured
g. The exposed earth (after excavation) is compacted; sometimes it is necessary to use landfill
After the excavation, the footings are erected by pouring concrete. Footings form the perimeter of the home and are wider than the container walls.