Treatment to Roofs

Flat roofs needs associative costlier and heavier water-proofing treatment as compared along with pitched or sloped roofs. The specification of material used for the reason should be such in which it performs the function of water-proofing as well as gives adequate thermal insulation. Stagnation of water on the roof is considered to be the root cause of leakage and dampness in flat roofs. This could be prevented through providing adequate roof slope and rainwater pipes. In case of RCC or RBC slab roofing along with proper grading above, a slope of 1 in 40 to 1 in 60 is desirable. Further to the slope, the size and the spacing of the rain water pipes or the outlets needs because of consideration for the proper drainage of the roof. In general practice, one 10 cm diameter pipe is considered appropriate for every 30 square meter of the roof area to be drained. The water proofing of flat roofs are shown in Figure 7 and Figure 8.

                                    Figure: Water Proofing of Flat Roofs

                         Figure : Water Proofing of Flat Roof Using Mastic Asphalt

The water proofing treatment for the roof might consist in laying bitumen felt directly over the surface of roof slab after painting the rooftop along with hot bitumen. The bitumen felt may be hessian based or fibre based. Depending upon the type of building, climate and atmospheric conditions of the site, the treatment with felts might be with four courses, six courses or eight courses. The four-course treatment is recommended for moderate conditions, whereas the six and eight course treatments are recommended for severe and extremely severe conditions respectively. Learner could refer standard text for details about four or six course treatment and treatment of sloping roof.