The promise of cheaper and quick delivery of housing units by the Delhi Development Authority (DDA) under its current housing scheme could be attributed in part to prefabricated technology, commonly referred to as ‘Prefab’.
Over 19,000 housing units are being made by the DDA under the now-open mega housing scheme using the prefab or off-site technology.
Prefabrication involves assembling of columns, beams, slabs, and walls in a factory or another site in a controlled environment, transporting them to construction site, and then assembling them at the site rather than the more conventional practice of transporting the basic materials to the site where all assembly is carried out.
Not only does this help the pace of construction, it also brings down the cost of the final structure and makes it difficult to personalise the structure by making alterations, like it is done in most of the DDA houses.
And what’s more, the technology helps keep the temperature inside the unit lesser than outside, creating a kind of thermal insulation.
Chief Engineer (Rohini) Sandeep Mehta said some 10,000 prefab units are being made in Rohini, nearly 6,000 in Narela, and 2,400 in Dwarka.
He is all praise for this technology as he says it helps solve housing problem for so many in Delhi as more houses can be made in lesser time.
K.T. Ravindran of the School of Planning and Architecture said under prefab technology, just the frame of the building is made on the site.
“Considering the large number of houses the DDA has promised to deliver over a period of years, there is no escape but to use this technology. A lot of time is saved as during onsite cement construction, a structure is raised and then one has to wait for some days for rigidity to set in,” said Professor Ravindran.
He, however, added that the only problem is that if the joints of a prefab structure are not fixed properly, it can cause problem of leakage.
The technology has been in use in Mumbai for some years now and came to Delhi in 2009. It has been in use in England as early as 3,000 BC, though not in its present form.
It is used specially in projects involving construction of similar units.
The DDA has already built flats for Economically Weaker Section in Dwarka using the prefab technology wherein pre-cast columns, beams, slabs, and staircases were brought in and flats were assembled at the site.
Chief Engineer (Dwarka) S.R. Solanki said the technology is faster, helps in good construction as a majority of structures is made in controlled conditions.
An official of Hindustan Prefab Limited, a government enterprise, said the technology brings down the cost of construction by as much as 30 per cent.
