Among all the building parts, which has captured maximum human attention? Possibly the roof — structurally a challenge to ensure it does not collapse; aesthetically important for it covers the whole building; functionally critical since it has to take on rain, sun or snow; and to top it all, constructing a roof over an empty space below demands high skill.
Accordingly many ideas have evolved across time in every settlement, some of which we have covered in the earlier essays.
People are obsessed not only with how the roof is built, but also with how it is seen, from above as a roof and from under as a ceiling.
Along a sloping site, say in hill station, what we see below are mostly roofs after roofs, in receding stepped fashion, which offer an attractive profile for the whole hill station.
Looking up from the interior of a space, we generally see flat white painted surface, which could appear predictable and dull for many people. As such, there have been experiments with the roof both in terms of materials and technology, to evolve an attractive roof.
One such method is to cast the RCC roof with inverted clay pots or shallow mud bowls set within as filler material. Conceptually it is a method to substitute the replaceable concrete by cheaper clay pots to reduce cost and weight.
As such, there are no structural problems or apprehensions about the performance of the roof. Once cast, the ceiling appears attractive with inverted pots, as if it’s decorative false roofing.
With the centring ready for the roof, the clay pots of chosen diameter are kept face down as per design, at designated spacing and pattern.
A thin layer of mud is spread around the pots to ensure they do not move during the concreting, steel reinforcements tied as per the advice of the structural engineer around and above these pots, electrical conduits are placed around the pots with no fixture overlapping with the pots and then the roof is cast.
The spacing for steel reinforcement needs to be specially designed based on pot size, room spans and such others, hence this idea does require a qualified engineer around.
The mud layer is removed from underneath after concreting, highlighting the pattern of the pots.
While the soffit of the roof shows an attractive pattern of clay pots, the upper surface is flat to take on another floor.
Of course, any pattern can be produced today by false ceiling, but they come at an extra cost, can be justified only at specific locations and are done with cheaper materials like POP (Plaster of Paris) or gypsum.
If we can build naturally and integrally to get a unique roof design, better to chose such right alternative methods over the more common place false ceiling methods.