Top Terrace Waterproofing


This standard operating procedure enumerates the scope of Waterproofing work in toilets to be executed in Tower area as specified in the approved drawings.


The respective Tower-in-charge is responsible to execute the work as per procedure.

Safety & protection:

PPEs like safety belts at height, helmets, safety goggles etc. should be used properly. 

Ensure the working area is kept clean for easy access.

Proper illumination to be provided during the work, if required.

Educate the workmen through pep-talk meeting. 

Preparatory works:

Cleaning of slab base and sides of beams shall be carried out as regards all those materials, mortar, oil etc. thoroughly by wire brush and the area shall be washed clean.

PVC sleeves should be removed.

Slab should be filled with water and next day should be inspected for leakages.

If Leakages found, then cracks should be open out by making grove and pressure grouting by socket should be done. After completion of treatment sunken slab should be again recheck for any leakages.

Ensure all plumbing lines are installed on top of slab as per slope specified in approved drawing.

Work Method:

Brick bats should be soaked thoroughly for about 15 minutes prior to their placing.

Cement mortar in 1:4 proportions should be prepared and laid on slab. Mortar mixed shall be used within 1Hour of preparation.

 Pre-soaked brick-bats shall then be laid in straight / radial, by inserting brickbats to a depth of about 15mm by light tamping with the help of mallets. Distance between adjacent layers of brickbats shall not exceed 25mm.

 Application of brick-bats shall proceed from one corner. Thiyya (level pads) for the same shall be given by Site Engineer, considering into account adequate slope towards rain water drain.

Mortar should be filled up to half height of brick bats and it should be cure for minimum 3 days. 

After curing is over, the surface shall be applied with a finishing coat of cement sand mortar in the proportion 1:4 with waterproofing compound (Fosroc Conplast X 421 IC) @ 150ml per bag of cement till top of brick-bats.

 Top coat shall be of neat cement slurry of adequate consistency and shall be done monolithic with topping of brick-bats with slope towards rain water drain.

Finished surface shall then be cured for at least 7 days by ponding and then tested for leakages, if any.


CBEC India