waterproofing in roof slabs of various buildings at mfl complex , taking out old damaged tar felt and existing heat protective layer ( thermocole slab ) from the roof , parapet etc . preparing the roof surfaces upto mother roof by removing all dust , dirt , cement slurry etc . by means of wire brush , chisels , scrappers , water etc . from the working site and disposal of the same beyond the compound and cleaning the site in all respect as per direction of engineer-in-charge . , providing and applying elastomeric liquid water proofing membrane with resilient acrylic polymers having sun reflectivity index ( sri ) of 105 on top of concrete roof in three coats @10 . 76 litre/ 10 sqm . one coat of self-priming of elastomeric waterproofing liquid ( dilution with water in the ratio of 3:1 ) and two coats of undiluted elastomeric waterproofing liquid ( dry film thickness of complete application /system not less than 500 microns ) . the operation should be carried out in mother roof , complete in all respect as per the direction of engineer-in-charge . , providing protective overlay of average 40 mm thick screed concrete of proportion ( 1 cement: 2 sand: 4 stone chips ) over the entire surface maintaining a slope towards the rain water outlet ( including chicken mesh ) . complete in all respect as per direction of engineer-in-charge .