Excalibur, a high-end, theme-based residential project developed by the Nahar Group, has received a five-star GEM rating from the ASSOCHAM Council. CWDB delves into its features and the methods utilised to design them. Located at Jacob Circle, one of the busiest parts of Mahalaxmi, Mumbai, Excalibur is a high-end, theme-based residential project. A redevelopment project under the 33/7 scheme, it entailed the construction of two rehab buildings and one for sale. In fact, Excalibur by Nahar is one of the fastest redevelopment projects completed in South Mumbai, says Ajay Nahar, Managing Director, Nahar Projects. Design strategy Built on a tight plot with marginal open spaces that were completely concretised, the project makes the best use of the site to accommodate the basic requirements of green building systems, achieving a five-star GEM rating from the ASSOCHAM Council. The building features various passive design strategies, like glass fibre-reinforced concrete panels (GRC) in the parking lot to provide abundant daylight and natural ventilation and greater ceiling heights in the apartments to facilitate thermal comfort for occupants. The implementation of GRC panels as cladding allows substantial amount of daylight and airflow in enclosed spaces while shielding users from external weather conditions, resulting in minimising the need for mechanical ventilation and lighting. Rainwater harvesting and onsite sewage treatment Incorporating sustainable features is essential to reduce the impact of buildings on the environment. This project has implemented a range of sustainability features to enhance the well-being of residents and minimise the environmental footprint. These include rainwater harvesting, onsite sewage treatment and solid waste segregation as well as recreational amenities. Rainwater from the rooftop is collected in a storage tank constructed in the basement. The rainwater tank is further connected to the flushing overhead tank; the stored water is used for flushing purposes, thus reducing the demand for freshwater. The excess water from percolation pits is recharged into the municipal stormwater drain to avoid wastage. For sewage treatment, the project has installed a moving bed biofilm reactor (MBBR) treatment plant on the ground floor, which can treat 31 kld of wastewater generated onsite. The plant treats grey and black water, reducing the burden on the municipal sewage line. Additionally, the project has a dual plumbing system for flushing, which covers the toilets of both residential units and common areas. The treated water from the sewage treatment plant is used for flushing. Waste management is also given significant importance. The building has a central waste collection yard near the organic composting system to segregate biodegradable and non-biodegradable waste. This practice ensures the proper disposal of waste within the building premises, minimising its impact on the environment. Further, the project provides recreational amenities for the well-being of residents, which encourage a healthy and active lifestyle. These sustainable features showcase the project's commitment to minimising its environmental footprint while providing a comfortable living space for residents. Sustainable practices, technologies and materials The project has also adopted sustainable practices during the construction process to preserve natural resources and prevent the disposal of valuable recyclable materials into a landfill. The entire interior blockwork is made up of autoclaved aerated cement (AAC) blocks that contain fly ash, a waste from thermal power plants. The lightweight nature of the blocks helps reduce the dead load, minimising overall steel and concrete consumption. Chemical mortar was used for the blockwork, eliminating the need for cement and water. All the broken blocks were used as filler material wherever required. MIVAN technology was adopted to avoid the use of external plaster. Materials like green-tinted glass from Saint Gobain and the ready-mix concrete (RMC) used contained a certain percentage of recycled content. The TMT bars used for construction were also manufactured using recycled steel. Proper storage of construction materials and their waste was ensured throughout to facilitate recycling and minimise overall waste production. Promoting EV use Going the extra mile towards sustainability, the project promotes the usage of electric vehicles (EVs) over conventional ones, reducing carbon emissions. Provision for a charging facility for four EVs is made on the ground floor. The electric system is designed considering future addition of electric charging on the podium level. “Despite the constraints of the site and the dense locality it is situated in, the project has successfully fulfilled the essential criteria of a green building and achieved a five-star ASSOCHAM GEM rating,” says Roshni Udyavar Yehuda, Director, Roshni Udyavar & Associates, who worked on this project.