The brick bat coba is used particularly for waterproofing of flat roofs, primarily RCC with some thermal insulation (mud phuska) in the coastal region. It consists of putting brick bats on roofs, to give a slope and then grouting the same with mortar admixed with various proprietary chemicals most in the nature of waterproofing compounds. In the new construction house, it provides an excellent slope in a moderate cost, so that the water drains away.
Though this conventional way of terrace waterproofing is prevalent, it is not a correct way of terrace waterproofing method, it just gives slope to terrace to drains away the water accumulated on terrace. Over the years, it has been followed and believed to be the most trusted waterproofing system which unfortunately is not true. Many times, it is said that it provides heat insulation which is also not true. This claim can't be quantified as it is not measurable. Moreover, it has been observed that the coba surface attains the same temperature as the bare cement slab during the peak hours in summer.
This conventional method has severe following limitations, hence it can't be called as a waterproofing method.