Concrete roof rules
The basic skill to cast it has percolated down to remote villages too, however over designed or wrongly mixed it all could be.
Look around today. Everywhere everyone is in a hurry to cast RCC concrete roofs. However, if this line is taken as a compliment for RCC roof, sorry it is not. It is a statement of concern, about a versatile material being indiscriminately used, including in areas such as sitouts where concrete roof is just not necessary.
Let us accept the fact that reinforced cement concrete roof, commonly called RCC or concrete roof, has been a great discovery. It has solved innumerable problems including providing security and opened up design options such as shell roofs which were never dreamt before. Though only qualified structural engineers know exactly how to optimally design these roofs, the basic knowledge and skill levels required to cast a roof has percolated down even to the remotest of villages, however overdesigned or wrongly mixed it all could be. No wonder, small bus shelters, not so permanent milk booths, park pavilions, storage sheds or village houses, which in the past were roofed with sheets or tiles, today get RCC roof. Projects tendered by the government compound this overdoing, by insisting upon concrete roof everywhere.
Steel and cement are among the production industries that consume humongous resources; hence have very high embodied energy. Of course, today they top the list of materials for being most popular and widely used, as such are seemingly irreplaceable.
Additional burden too
Most of us forget the additional burden of the temporary support called centering or shuttering, which after some use becomes a total waste. Among all the needs of water for mixing and curing, it is the roof which singularly consumes the largest quantity per square feet. Segregating the steel reinforcement and concrete from the discarded old buildings or irreparable cracked roofs is hugely time- and resource-consuming. Even if we use cutting machines and succeed in this segregation, it is impossible to reuse old concrete but for some land fill.
Unlike any other traditional roof, a concrete roof once cast can never be returned to its original ingredients, and will continue to burden the earth for a long time to come. Till recently, concrete roofs were labour intensive, hence provided the much-needed labour opportunities.
Now-a-days, manual casting is being replaced by Ready Mix Concrete in large cities, further reducing on people benefits. Considering concrete is far from being eco-friendly, the way it has relegated all earlier roof options to the back seat is both amazing and alarming.
Having said this, let us realise the solution does not lie in discarding concrete, but in using it judiciously. Also, there are numerous methods such as arch panel roof, filler slabs and ferrocement technology which basically employ steel and cement, but create alternative options for construction.
In these days of rising price of RCC roofs, it is time to explore such alternatives, for both ecological and economical reasons.