The slab which is casted on surface of the wearth is called a Ground slab. This type opf slab is used in Basement floor.

There are two types of Grade slabs:

Usually after casting Plinth beams. Sand is filled at an height of 0.15m and then Sand level is rammed. Then PCC is poured on sand upto a height of Plinth beams. Its an economic way of constructing ground slab which use majorly in India.

In high rise buildings after constructing Plinth beam the termite control is done in between the beams and then polythene sheet is laid to avoid termites inside the slab and then steel mesh is provided and concrete is filled. This costs more when compared with the previous one and requires more concrete than first one.