1. Roofing system for sloping roofs: A large residential premises near Pune

The conventional RCC for sloping roofs poses problems of casting to slope, waterproofing and consequently durability.

The roofing system adopted here is of precast ferrocement troughs of about one meter width placed adjacent to each other. These form formwork for the insitu concrete and also form a part of the stiff structural roofing element. The ribs formed by the troughs and topping over the troughs are done insitu using same mortar as one used for ferrocement precast elements. This mortar also developed strength of the order of 45 N/mm2 and has very high impermeability. This would lead to a long term durability. Fibers are used in the insitu mortar for crack control. Ridge beams, barge boards for the sloping roofs are also done using ferrocement.

The appearance from soffit is a pleasing from finished ribbed roof. From top side impermeable screed renders watertightness. For aesthetic consideration roof is finally tiled from top. The time is saved because the precasting of the troughs is done along with the foundations and walls. The cured troughs can be lifted with chain pully block and placed over walls/ rib beams. The time required for making formwork, reinforcement fixing, and full curing can be saved. The economy can be achieved if there are several number of such dwellings. The cost of setting up the precast yard will then be distributed over a large roof area.