Up and Above

The sky is the limit when it comes to roofing options, observes CW. Roofs, just like the structures they cover and secure, have evolved - and how! From traditional RCC roofs to photovoltaic-installed rooftops that help convert sunrays to energy, roofs have become so much more than a means of shelter. ´The usage of roof space has exploded,´ says Rahul Kadri, Architect and Urban Planner. ´Earlier, we never used our roofs for activities. But now that there is shortage of space, roofs are being used more than ever before; there are gardens and even lounges on roofs. That is a huge growth.´ and even Abhin Alimchandani, Proprietor, STUP Design Forum, and Joint Managing Director, STUP Consultants, agrees, saying, ´There have been a lot of new materials in the roofing sector.´ Apart from the housing sector, roofing has seen immense growth primarily through increased construction of modernised spaces such as malls, airports, metro rail projects, IT parks, SEZ, and multi-utility and community spaces. ´Apart from housing, the maximum demand will come from educational institutions,´ observes Kadri. ´There is a shortage of school and colleges.´ And Alimchandani adds, ´There is tremendous potential going forward; there will be a lot of investment in roofing, particularly prefabricated roofs, through industrial buildings and logistic facilities. There is a lot of expectation from the infrastructure sector and the development of 100 smart cities.´ Once dominated by RCC and asbestos, the sector is now making way for more innovative and personalised roofing technologies. ´Projects are trying to speed up the roofing process, hence steel roofs, overdecks, etc, are gaining popularity,´ shares Deependra Prashad, Principal Architect and Sustainable Design Consultant, DPAP. ´Still, experimentation in the housing sector is lower as residents go in for more conventional RCC structures.´ And Kadri says, ´Green roofs have been the most innovative roofing system!´ Whatever the material or technology used, with a gamut of housing and infrastructure projects on the anvil, it is evident that demand will witness unprecedented growth. CW lists some landmark projects in roofing that are indicative of what´s on offer. Prof Charanjit Singh Shah, Founder Principal, Creative Group Kalzip Project: Swami Vivekananda Airport, Raipur Comprehensive Architecture and Engineering Consultancy: M/s Creative Group, New Delhi Principal Founder: Prof Charanjit Shah Principal Architect: Ar Gurpreet Shah Executive Director: Er Prabhpreet Shah Requirement: Column-free roof. Smart features: Versatile sheeting, can take any shape and size. The airport has ´double-curved roofing´ with no clip off, there´s no leakage if maintained properly. Won´t rust and is maintenance free. Technology: The gutter, mild steel sheeting is double skin and insulated. Time: 15-20 days. Challenge: To prevent condensation on the roof owing to variation in temperatures in the airport and outside. USP: Kalzip aluminium sheet has a good life and is recyclable, maintenance-free and long lasting. Market share: 5 per cent of total roofing in India. It will be a booming market in the next five years. Area covered: About 18,500 sq m. Cost of roofing: Rs 15 crore. Materials used: Aluminium roofing, 52-mm, double skin insulated Kalzip profile roofing, which provides sound and heat insulation in the terminal. Maximum demand for roofing: Residential. Suitable for: Column-free and large-span structures like terminal buildings, sports facilities and metro stations. Raghu Balan, Executive Vice President - Quality, Safety and Technology, Sobha Ltd Clay tiles Project: Sobha Aristos, Bengaluru Requirement: Durable roofing. Smart features: Designed for long-term performance, maintains colour, long-lasting protection, economical, can sustain high winds, requires limited maintenance, traditional elegant appearance, ability to insulate, keeps inside temperatures warm in winter and cool in summer. Technology used: Fixed using adhesive Cerabond 27. Time taken: Six months. Challenges: Requirement of appropriate manpower. USP: It has durability beyond compare, saves energy costs, and offers protection like no other roofing material. Market share: Clay tiles are widely used for roofing. Area covered: 19,000 sq ft. Cost of roofing: Rs 50-60 per sq ft (depending on quality of tile used). Materials used: Clay tile, Iberica Ultra Tile and Cerabond 27. Suitable for: Villas and row houses with sloped roofs. Roshni Udyavar Yehuda, Head, Rachana Sansad´s Institute of Environmental Architecture Thermal sensitive roofing Project: SNDT Campus, Mumbai Requirement: To provide thermal comfort to occupants through retrofitting. Smart features: Reduced heat gain; it has vents to remove hot air and uses the radiative barrier below the roof to do so. Technology: High albedo paint on the upper side with SRI > 0.5; turbo ventilators suck air inside spaces and throw it outside; the radiative barrier is a silver-coloured material with an air gap of 100 mm and low emissivity; as a result it doesn´t emit any heat inside. Time taken: Design took a month, execution a year. Challenge: Retrofitting the roof without disturbing the exterior of the building. USP: Good solution for making a building environment-friendly. Market share: Less than 0.5 per cent. Area covered: 12,610 sq ft. Cost of roofing: Rs 11.56 lakh. Materials used: The existing AC sheets were retrofitted with translucent polycarbonate sheets for daylighting; multiwall polycarbonate panels at truss level (above 4.4 m) for noise and thermal insulation; radiative barrier material (North and South, East roof slopes) below roof with 100-mm air gap with emissivity < 0.1. Maximum demand for roofing: Residential sector. Suitable for: Retrofitting of existing structures. Deependra Prashad, Sustainable Design Consultant for Indira Paryavaran Bhawan, and Principal Architect and Sustainable Design Consultant, DPAP Solar photovoltaic roof Project: Indira Paryavaran Bhawan, New Delhi Requirement: Equate building´s energy usage with energy produced through solar photovoltaic, roof or panels. Smart features: RCC made into a highly insulated envelope, provides 930 kw peak power. Technology: One sprayed-on puff layer. Time: Three years for overall construction. Challenges: To get adequate energy to produce the amount of power to make the building net zero. The basic footprint is 3,000 sq m; to reach net zero level, 6,000 sq m of space was required to install solar panels. This was achieved by spanning the space in between the two blocks - north and south zones - using a stainless steel space frame, protruding 6 m from all sides, and a projection on the fourth floor. Being a net-zero building, the effort was to equate the building´s energy usage with the energy produced by the photovoltaic cells. Thus, the idea was to reduce electrical loads as much as possible with a highly energy-efficient and insulated envelope. The roof was taken up to R-20, where one sprayed-on puff layer has been used along with therm-tech tiles with high solar reflective index. USP: Solar roofing gives shade, produces energy and renders a defining architectural look to the building. Market share: Currently not substantial, but has great growth opportunities. Area covered: 6,000 sq m. Cost of roofing: About Rs 20 crore. Materials used: High albedo tiles with high solar reflective index. Maximum demand for roofing: Residential. Suitable for: A variety of structures; the rooftop area available is fantastic and things should look up with the new solar policy of the government. To share your views, write in at feedback@ASAPPmedia.com