Coat of paint to cool roof: Bengaluru health clinics reduce indoor heat by over 3°C

Bengaluru: In a city increasingly grappling with rising temperatures and urban heat stress, an initiative aimed at making govt healthcare spaces cooler and more comfortable has shown promising results. Two primary health centres (PHCs) in north Bengaluru — Agrahara and Amruthahalli — recorded a drop of more than 3°C in indoor temperatures after reflective “cool roof” paint was applied to their rooftops.The pilot was undertaken by Bengaluru North City Corporation (BNCC), especially in public buildings catering to vulnerable groups, including elderly patients, pregnant women, and children.According to findings from the pilot study, the reflective-albedo coating significantly reduced heat absorption by the buildings. At Agrahara PHC, roof surface temperatures dropped by nearly 9°C, from 48°C to 39°C, after the painting. Officials noted that indoor temperatures, which earlier acted as “heat traps” and remained warmer than outdoor conditions, were brought down substantially after the coating was applied. The indoor cooling impact was measured at 3.4°C in Agrahara and 3.2°C in Amruthahalli.As part of the pilot, around 80 litres of reflective paint was used at the Agrahara PHC, covering nearly 1,442sqft of roof area, while 120 litres were used at Amruthahalli across 3,681sqft, including parapet walls. Officials said the paint used was a polyurethane-based waterproof reflective coating costing approximately Rs 575 per kg, while labour charges for applying two coats stood at Rs 35 per sqft.Encouraged by the results, authorities are now considering expanding the initiative to nearly 50 additional PHCs and govt buildings.According to the BNCC commissioner, Pommala Sunil Kumar, Rs 2 crore was set aside for this initiative from the corporation’s budget, and the technical support for the initiative was provided by C40 Cities.During implementation, engineers encountered rough roof surfaces, cement crumbles, cracks, and seepage issues, which were repaired and smoothened before the cooling paint was applied. Officials also said doctors and staff at the PHCs have reported improved comfort levels after the intervention, while patients found waiting areas more breathable during peak summer afternoons.Speaking about the initiative, Chandrashekar, executive engineer at BNCC, said, “This painting works in two ways. During summer, it reduces the temperature by around 3°C. During rainy season, it acts as a leak-proof and damp-proof protection. This paint coating is effective in summer, winter, and rainy seasons.”