Roofing and cladding: 7 case studies in hi-performance innovation
Panels of various composite materials, glass, polycarbonate and metal sheets remain the most popular roofing and cladding options in India. Architects are innovating to produce attractive and high-performance roofs and facades. In this article, we bring you seven case studies in roofing and cladding, some underway and some fully executed. But is India ready for high-end innovation in roofing and cladding?
#1 A residence with modern skylightsSkylights in roofs have been in use for long, mostly in covered courtyards and indoors as ventilation shafts for being functionally efficient, [albeit] differently to vertical openings/windows, and adding aesthetic value to a space, observes Architect Indrajit Kembhavi of Kembhavi Architects.
Panels of various composite materials, glass, polycarbonate and metal sheets remain the most popular roofing and cladding options in India. Architects are innovating to produce attractive and high-performance roofs and facades. In this article, we bring you seven case studies in roofing and cladding, some underway and some fully executed. But is India ready for high-end innovation in roofing and cladding? _____________ #1 A residence with modern skylights Skylights in roofs have been in use for long, mostly in covered courtyards and indoors as ventilation shafts for being functionally efficient, [albeit] differently to vertical openings/windows, and adding aesthetic value to a space, observes Architect Indrajit Kembhavi of Kembhavi Architects. With the availability of laminated glass and special 3M film to cut out radiation, skylights can be designed to draw in ambient natural light and enhance the aura of a space. For safety, Kembhavi incorporated a metal trellis below the skylights of a residence in Hubli. This casts shadows that change according to the time of the day and season. Skylights are not necessary a feature of standalone homes alone. With intelligent planning, they can definitely be used in high-end apartments as well as homes and will add a lot of character and expanse to the space, he adds. Cost: Laminated glass: Rs 700/sq ft 3M film: Rs 300/sq ft #2 Solar roof for a responsible institutional building A comprehensive solar panel system using one of the most efficient PV modules available is being installed on the 60,000 sq ft rooftop and south facade of Atal Akshay Urja Bhawan, the upcoming head office of the Ministry for New and Renewable Energy, according to Naveen Thomas, Vertical Head of Corporate Architecture, Edifice Consultants, the project architect. With the Government actively endorsing energy-efficiency, it makes sense for institutional government buildings to lead the way in minimising environmental footprints. Atal Akshay Urja Bhawan is expected to achieve net-positive energy status as a result of the solar panels, cavity walls to reduce heat ingress, energy-efficient materials for floors and ceilings, and energy-efficient electrical equipment (such as chillers, cooling towers and DG units), explains Bedanta Saikia, Vertical Head of Science and Technology. Edifice Consultants. All these measures, expected to cost Rs 80 lakh, will help the building consume 1,764 kW-hr less energy units than what would have been consumed had no energy-efficient measures been applied in the building (5,126 kW-hr energy per day versus 6,890 kW-hr). At over 250 working days with the cost of Rs 8.50 per unit, the building will effectively save Rs 37,48,713 in electricity bills per annum, which means the extra expenditure on energy-efficiency would be recovered in just over two years. #3 Designer cladding + roofing for an office In Aurangabad Industrial City (AURIC), India’s first greenfield, smart industrial city, a 16,660 sq m building housing administration and commercial office features a highly aesthetic double façade composed of perforated aluminium screen and glass. The design is inspired by Aurangabad’s historic structure Bibi-ka-Maqbara, explains Rahul Kadri, Partner & Principal Architect, IMK Architects. In the atrium, a mild steel roof truss supports multiwall polycarbonate sheet roofing. “Multiwall polycarbonate sheet roofing is lightweight and hence requires a lighter truss, but does not compromise on blocking the glare and minimising heat gain and air-conditioning cost for the large atrium volume,” adds Kadri. “We chose mild steel for being durable, structurally flexible, having higher load-carrying capacity and being amenable to fast construction as it can be fabricated offsite and assembled onsite.” Highly reflective tiles cover 3,000 sq m of the 4,920 sq m roof, alongside 15 kWp solar PV cells generating 21,874 kWh, or 6.17 per cent of the 3,54,318 kWh annual lighting consumption. The use of high-performance materials helped this building achieve IGBC Gold Performance. Cost: MS roof truss: Rs 150-220/sq ft Danpalon 3D Lite polycarbonate sheet: Rs 120-300/sq ft High reflective tiles: Rs 25-100/sq ft, depending on the material and thickness of the tile #4 Contemporary cladding stands out on an educational building The façade of the School of Architecture at the Nitte Meenakshi Institute of Technology in Bengaluru highlights the corner of the building as an accented pylon and demonstrates how a singular material can be used to protect the fenestration. Ace Group Architects chose to accent the corner with a shade louver—and gave it a traditional look with contemporary cladding panels from Fundermax’s Max Exterior Nature range, juxtaposed with custom-created modules that look like solid wood verticals, glass and mild steel. “We had the modules and panels customised to fit the non-standard installation,” shares Dinesh Verma, Principal Architect, Ace Group. “Special cleats were fabricated to wrap the panels around the steel sections, which then supported the louvers. The side-hung openable glass panels behind these louvers were handled with extra care, to ensure they could open without hindrance.” “We opted for Fundermax because of the possibility to customise the panels for the best fit, the quality of the panels, and the network of trained and experienced authorised business partners across the country to support onsite installations,” he adds. “The panels are extremely weather-resistant, especially when exposed to the harsh suns from the west and south, and also fire-retardant and maintenance-free.” #5 A factory with a colourful twist Veeline Media needed a cladding solution that was pattern-based, both vertically and horizontally. Tata BlueScope Steel proposed the use of Lysaght Custom Orb® and Lysaght Trimdek® (combination of cool Cottage Green and Surfmist) for the horizontal wall cladding, and Lysaght Trimdek® (in Surfmist) for the roof. The interplay of colours with the profile’s sinusoidal shape lent the structure a harmonious look. Implementing this solution was tricky. “Geometric designs made it complex to optimise the material. To get the desired finish, we cut the inclined colour bands and panels at site with non-standard flashings to cover the edges,” explains Piyush Nahar, General Manager, Marketing, Tata Bluescope Steel. “Hat-end lap flashings helped divert rainwater through the inclined parts. We adjusted the RCC wall at the base height for minimum wastage while lapping the horizontal sheets.” The outcome was a customer-centric roofing solution combining superior aesthetics with greater functionality and long-lasting performance. #6 Airport design takes off with low-cost origamic metal roofing “We’re giving a new airport in Guwahati an origamic roof inspired by Icarus, a mythological figure who dared to fly,” says Anand Sharma, Founder & Partner, Design Forum International. BIM helped Sharma’s team design the new roof; to better visualise the angles, slopes, and gutters; and mathematically model the shape of the roof as desired. Structurally, the standing seam roof is composed of two galvalume sheets (forming the roof membrane) sandwiching rockwool insulation, achieving an overall thickness of 165 mm. “We chose galvalume sheets, a zinc and steel composite material, to stick to the strict budgetary restriction and cope with the highly corrosive environment,” explains Sharma. Guwahati sees heavy rainfall with high wind velocity. Aluminium at the gutters and edges allows better resistance against corrosion. A siphonic drainage system replaces the traditional gravity-based drainage system for more effective drainage. The end result is a large span roof created at a relatively lower cost. Cost: Galvalume sheets: Rs 1,000-1,500 per sheet; but with installation, accessories, gutters etc, Rs 4,000-4,500 per sq m #7 Precoated GI sheets with insulation cover a railway station Indian Railways is aggressively working on the revitalisation of railway stations to offer integrated transportation services, enhance the commuter experience and cater to higher footfalls. Several station redevelopments seek to utilise the commercial potential of such locations. In this context, Gian P Mathur, Managing Director, GPM Architects and Planners, points out: “The roof plays a key role in defining a project’s aesthetics, a critical factor to attract users, besides ensuring that it is sustainable, strong, easy to install and efficient.” At Tirupati railway station, a redevelopment envisioned to integrate 29 acre of station complex with other infrastructure facilities, Mathur has opted for a conventional material for the concourse area—GI sheet—with a twist to overcome the traditional challenges associated with the material: limited length availability and prone to cracking, rusting and corrosion in the long run. “We have opted for precoated GI sheet roofing involving a double-layered, 50-mm-thick metal sheet packed with PUF (polyurethane foam) insulation to absorb heat and keep the space comfortable for passengers,” says Mathur. “Precoated GI sheets are lightweight, available in longer lengths, even going up to 15 m for a single piece, durable, resistant to heat, which prevents discolouring in high temperatures, and can be profiled and cut onsite, making them amenable to any design.” Single-layered metal sheet roofing for platforms enhance their structural appeal and functionality. Cost: GI sheet: Rs 270-290 per sq ft Few takers in India for high-end In conversation with CW, material providers elaborated upon the use of high-end materials, sharing examples from overseas to strengthen their case. For instance, consider the use of skylights as an architectural feature. Skylight roofing greatly enhances aesthetics, lets in natural light and reduces heat gain without letting go of indoor comfort, explains Niraj Borikar, Country Manager, Danpal. “Skylights protect against harmful UV rays. Besides, polycarbonate panels as skylights are easy to install and work with.” Polycarbonate is a popular material for skylights. Danpal’s polycarbonate skylight roofing system uses Snap-On interlocking dry-glazed connectors made of aluminium or polycarbonate. It is lightweight and, hence, doesn’t put undue pressure on the structure and is easy to install. It also comes in a wide array of colours, finishes, aspects and spectacular effects. Danpal recently completed an innovative application of Danpalon 16-mm panels in amber for a supermarket, closely surrounded by a residential tower, in North India. The translucent polycarbonate panels helped conceal the supermarket from the residential tower while allowing in natural sunlight and reducing inner glare. Switching from polycarbonate to glass for skylights helps increase indoor brightness, making indoor spaces more appealing, says Rajiv Balaggan, Sales Head, Architectural Glass, Pilkington Glass India. “This has been the experience at India Buildings, a heritage building in Liverpool, UK.” While the original rooflights of the Regency Suite and Banking Hall of the building were made of polycarbonate, during an ongoing refurbishment, slender fittings have been used to mount advanced glazing on a minimalistic steel frame for the clearest possible view of the sky and to allow light to flood the rooms. Pilkington’s Planar™ frameless glazing system was chosen to fasten to the support structure, thanks to its low-profile design. The double-glazed units comprise a 10-mm outer pane of Pilkington Optifloat™ Clear, a 16-mm air-filled cavity and a 13.5-mm laminated inner pane of Pilkington K Glass™ low-emissivity thermally efficient glass. What’s interesting is that the Planar™ system has only one application in India, albeit for walls not roofing, in Antilia House, Mumbai. Demand for high-end roofing and cladding is limited mostly because users aren’t aware of the differences between conventional systems and high-end materials, according to Balaggan. For instance, the Planar’s SentryGlas® interlayer is five times stronger than conventional laminating materials. This ensures that the system can stand up to significant weather forces, such as snow-loading during winter. Schueco offers aluminium roofing window system AWS 57 RO.HI for sophisticated skylight constructions and/or large-scale roof glazing, when combined with Schüco FW 50+/FW 60+ façades. “The system can be used in an almost unlimited way owing to the two different thermal insulation standards, the different heights of the outer frame and the design options,” explains Pratik Doshi, National Manager, Facades, Schueco India, while sharing images of a cultural building in Germany using this system. In India, Schueco has completed a handful of installations with AWS 57 RO.HI, one with a rain sensor. High-end solutions are yet to penetrate the market, though, he observes. Fundermax offers panels that are mostly used for façades, balconies, soffits, pergolas, railings, gates and sun shades. While most façade installations are based on the principle of a rear-ventilated façade system, the company has also developed standardised installation systems to withstand extreme weather conditions in the Indian subcontinent, shares Ashwani Khanna, AVP Marketing, Fundermax India. All these systems are long-lasting, easy to maintain and easy to clean. -Written by Charu Bahri