Traditionally, most roofs were made up of varied parts such as beams, tiles, stones, mud or thatch, where each was lifted into the desired position in a given sequence. Rarely, except during fixing of domes and vaults, was a full temporary support system called as shuttering or centering. Today, shuttering has become an inseparable part of roof casting, demanding much extra efforts and expenditure, all for a temporary arrangement.
Those who have commissioned a building know how it's imperative that we stop all other floor works, wait for shuttering people, worry about the perfection in levels and then wait again till it's all de-shuttered or removed.
Arch panel roofing system helps in dispensing with shuttering, hence makes a big difference in time and cost. Technically, it transfers roof loads the same way as a jack arch roof does, using the curved arch profile. While jack arch work is done in situ , the arch panel is made outside the building, in the yard around.
A long arch profile is made with mud on ground, to be used as the template base for the panels. Small bricks like WPC (Water Proof Course) bricks, cladding bricks or such other ones with good compressive strength and adherence quality are placed flat faced along the curve to achieve the arch shaped panels. The size of the panels would depend upon the blocks we use, which could be between 16 to 18 inch width, 40 to 44 inch length, 4 to 6 inch rise within the curve. The joints get a 6 mm rod in between and are filled with rich mortar min. 1:3 proportion, properly cured with water and carefully stacked.
Simultaneously, required size of RCC beams are precast on the site, with small length of open-ended reinforcement rods on top. All these preparations for beams and panels could be completed while the wall reaches the roof height. After properly curing the wall top, these beams are lifted up and placed across the wall supports to match the length of the panels. Nominal vertical pole support could be provided for the beams, during work in progress. Then the panels are lifted up, placed along the precast beams, joints filled with water-proof mortar, the valley between two panels tied with G.I. wires and levelled with concrete to get the next floor.
While the roof bottom appears rich with beams and curved profiles below, on top it would be like any other flat RCC roof. The panel roof is best suited for any square or rectangular room within 15 ft. width and easy to achieve with minor attention and training.
All normal building usages can be managed and any length of roof achieved by this method. Additionally, the fact that arch panel roof is the among the lowest cost roofs today, ranks it high among eco-friendly roofs, where modern technology and traditional roof concepts merge together.
(The writer is an architect working for eco-friendly designs and can be contacted at varanashi@gmail.com)
