Raft foundation construction details

This construction article provides the detail construction methods for raft foundation of a building. The raft foundation is conducted for the multistory buildings or building having heavy loads.

Step 1: Initially, the surveyor should begin exaction and as soon as the survey is completed then exaction is carried out to the desired level on the basis of the validated shop drawings.

Throughout excavation, precaution for safety should be undertaken, the entire area should be guarded and everybody should utilize PPE at site.

Step 2: As soon as the final phase of the exaction is completed then the surface should be consolidated with plate compacter as the area is small and it is not difficult to apply the roller compacter. But 95% compaction should be performed with compaction test.

Step 3: After getting the passable results of compaction test, 75mm or 100 mm blinding concrete is arranged. Blinding concrete should be garde 20/20 SRC (Sulphate Resisting concrete).

The blinding concrete facilitates to arrange a solid and flat surface for the reinforcement of raft foundation.

The curing polythene sheets should be arranged instantly after finishing and when the concrete is set, it should be substituted with hessian cloth and should be retained wet unless the surface becomes fully dry.

Once the blinding surface becomes dry, water proofing of surface should be started according to sanctioned specification.

Step 4: Once water proofing is done, perfect planning should be undertaken for the shuttering work, all material should be retained on a plate form and steel bars should be installed with adherence to sanctioned shop drawings of the surrounding. All working space should maintain neat & clean to get rid of accidents at site.

Upon the completion of the reinforcement work, the contractor should sanction it from the supervision consultants for pouring the concrete.

Raft foundation construction details