please tell me the procedure of bb.coba for terrace waterproofing and please sug

All existing treatment, coatings on roof slab top is to be removed and surface cleaned by hard wire brush and washed with water. The surface should be free from any oil, grease, dust etc. Remedial measured by provided to all structural cracks. Expansions joints should be treated as per standard practice.

All non-structural cracks more than 0.5 mm wide and construction joints if any, should be cut in “V” shape, cleaned with wire brush and washed, the cracks are then filled by polymer modified cement or mortar using acrylic polymer, with addition cement slurry mix is spread upon cleaned SSD roof surface. Over this 15 mm thick cement, sand mortar, 1:4 admixed, with water proofer is laid.

BRICK BAT LAYING
On the above green mortar, a layer of brick bats, soaked over night in water, is laid, having an average thickness of about 110 mm, about 70 mm near rain water pipe and 150 mm at ridge.

The gaps between the brick bats are generally kept between 15 and 20 mm. These gaps are filled with cement sand mortar, 1:4, admixed with waterproofer. In hot and dry weather, the surface should be covered with wet gunny bags immediately after finishing. Curing should start next day and continued for 7 days.