"15 per cent of heat in a building can come through roof, which is why it is important to insulate roof of a building,' say many architects. The best way to insulate roof is to create a rooftop garden. In the industrialised countries, roof-top gardens are becoming a norm, Green roof tops not only help cut down a building's energy consumption, but have an aesthetic value. In the US many building owners prefere roof tops partially covered with vegetation because bsides saving energ, they also reduce runoffs. Many green buildings in India are also adopting such roof-tops dens. GBC building in Hyderabad is among them.