SATHYA PRAKASH VARANASHI says although a whole lot of established concepts continue to be employed, occasionally when a new idea springs up, we need to explore it or even employ it

The human mind never ceases to think and explore, even when we know that all the innovations may not be beneficial. On a comparative note, the building industry does not indulge in continuous and steady research; hence a whole lot of established concepts continue to be employed.

The last century has seen innovative roofing ideas such as hyperbolic structures, catenary curved vaults, tensile membranes, domes without formwork, prefabricated shelters, geodesic domes, ferro-cement roof panels, space frames, and pre-engineered structures.

Mostly known to architects and engineers, these high-ended ideas demand a thorough knowledge of roof behaviour, technological expertise to manufacture the components and skilled labour force to execute them at site. However, these conditions do not mean they should be excluded from routine constructions.

Funicular shells also belong to this set of alternative solutions. Many architects have used this idea extensively.

Shell roofs are most economical in short spans of 1.5 to 3 metres, so the roof area is divided into grids, preferably square, even though rectangular shapes are also workable.