A live demonstration on Raft versus Pile Foundation
If the gaps of footing are nearer, a raft foundation is recommended. Often, basements are created for particular purpose imposing to implement raft foundation. Usually, a raft foundation refers to a floating foundation that includes the ground completely to disperse load.
Pile foundation is mostly used if the spacing of footing is big & soil is costly in nature & it is not reasonable to excavate complete depth of this costly soil below the footing. If the spacing of column is big, raft foundation becomes expensive.
A raft foundation is ideal for feasibly inconstant soils, or soils which are extremely flexible. The raft system decreases the pressure on foundational soils. In some cases, a pile foundation is utilized in equivalent situations as a raft foundation. Piles should be set up intensely to spread to a strong strata of material, like gravel or bedrock.
A raft system will be perfect in some conditions where the depth of silt, sand or fine soil is very deep to develop a pile foundation. A spread footing is also ideal for feasibly unsteady soils. A spread footing needs excavating to a specific depth under the site grade, and considerably wider as compared the footprint of the house, and backfill with condensed, structural gravel fill. As soon as it is positioned, a standard concrete foundation is founded on the structural fill.