Brick Bat Water Proofing Treatment

• Existing waterproofing treatment shall be removed till RCC slab is exposed. Surface of the slab shall then be inspected. If any honeycombing or cracks are observed then these shall be treated as per specification for treating cracks.
• Entire slab surface shall then be grouted with cement slurry made with 1 part cement and 0.60-part water. This type of grouting is surface grouting onlyand not deep into the body. This slurry shall be spread over the slab surface and brushed into concrete using squeegee, brooms and brushes.
• The surface shall then be covered with cement + clean sand mix in proportion 1:4 by volume with a waterproofing plasticizer added at recommended dosages. The thickness is about 25-40 mm.
• Brick bats shall then be laid on fresh mortar starting with brick on edge at the central portion and gradually using smaller brick bat pieces as one goes to the rain water down take pipe side. The levels should be so adjusted that an overall slope of finished Brick Bat Coba of 1:100 is achieved. Preferably water should be drained along both longer sides of the building so that the water travel path on terrace is shortest. Gaps between brick bat pieces should not be more that 20 mm. Brick bat surface shall then be cured for 7 days by ponding water over it.
• After curing period of brick bats the top screed shall be laid in 1:4 cement sand mortar with a suitable waterproofing plasticizer and polypropylene fibers 125 gms per bag of cement. Surface shall be finished smooth and marked with tile marks at 300 mm c/c both ways. The surface shall be ponded for 21 days for curing. Final slope of min 1:100 shall be ensured. There should be no accumulation of water anywhere over the terrace.
• The junction of parapet and side wall plaster should have the coving (watta) or rounding as shown in sketch. The invert level of rain water down take pipes should be minimum 1" below the finished coba surface near parapet.

• China Mosaic tiles can be optionally applied at the top and are not necessary.

The water overflowing from the overhead watertank is seen flowing on the slope and escaping through the hole made for rain water outlet pipe.

This check ensures that in the monsoon, rain water will similarly make way along the slope.