Up and Above

01 Mar 2015 Long Read

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

Related Stories