Environmentally friendly designs and cost-saving building techniques will be used to install lifts in some of the city's oldest public-housing estates. There are 35 blocks in 12 estates, most of them built in the 1960s and 1970s, that do not have lifts. The Housing Department plans to install lifts in all these buildings. It intends to use 'precast lift shafts' and a 'machine-room-less' design, which would cut costs, shorten the construction period and reduce the nuisance to residents. Bik Shui House, a seven-floor block in Shui Pin Wai Estate, Yuen Long, will be the first to get lifts using the precast technique. Leung Sai-chi, a district management head with the department, explained that the different parts of the steel shaft would be prefabricated and welded together at the site. Energy-saving and low-noise lifts would be installed in the shaft. Compared with the traditional way of building a concrete shaft onsite, the new technique is expected to shorten the construction period from 22 to 11 months and save about HK$8 million each. 'There are some 200 families and 90 elderly residents living in the block. This creative technique can largely reduce the noise and minimise the nuisance,' he said. The lift will be designed so that a machine room will not be necessary. The machine room, found on the roof of most high-rise buildings, houses the traction machinery and control panels. Mr Leung said the new design integrated these parts into the lift shaft so that a dedicated room was not needed. The department first used the new design in Hing Wai House on the Tai Hing Estate, Tuen Mun.