SINGAPORE - From 2019, all the rooms in one-third of new HDB flats sold will be pre-fabricated as a whole - as part of a push that is expected to shorten construction time and lower costs in the long run.
Entire rooms will be constructed in factories elsewhere, before being assembled on-site. They will come with finishes including floor tiles, window frames, flooring and a lick of paint.
Bathrooms for all new projects will be pre-fabricated, with copper piping, partial tiling, window frames and a waterproofing system.
Currently, the construction time for Build-to-Order projects is around three years.
Said a HDB spokesman in response to The Straits Times queries: "As contractors become familiar with Prefabricated Pre-finished Volumetric Construction (PPVC) construction, we will try to shorten the construction time."
What is clear is that the method will cut down on the manpower needed in the construction industry, which has long been reliant on foreign workers.
Installing the PPVC rooms and bathrooms will improve project productivity - the amount of floor area completed per man day - by 50 per cent and 10 per cent respectively, the spokesman said.
It is part of the HDB's drive to improve its productivity by 25 per cent in 2020, compared to 2010.
Speaking at the annual HDB Awards Wednesday night, Second Minister for National Development Desmond Lee said the agency has been on track with its goal given the use of technology.
"HDB can construct a four-room flat in 182 man-days today, compared to 205 man-days in 2010," he said.
In the short run though, there will be some adjustments, as the industry grapples with investing in costly technology.
A HDB spokesman said there would be higher construction costs of about 1 per cent for the prefabricated bathrooms and 8 per cent for the PPVC rooms per project, though these costs are expected to come down over time. But she added that these are not likely to have an impact on flat prices, "as the HDB takes into account the location, design features, individual flat attributes, and prevailing market conditions".
But in the long run, says property analyst Ku Swee Yong, chief executive of International Property Advisor, prices should come down over time as construction firms "reap the benefits of economies of scale, reduced interest expenses and risk".
Quality will also improve, said the HDB. For example, the units, built and monitored in a controlled factory environment, are supposed to be more uniform and of better workmanship.
There are also fewer joints, which inproves the water tightness of wet areas.
The PPVC method was piloted in Valley Spring @ Yishun, where construction for the 824 units there started in March this year (2017). Prior to that, the HDB had tested the Prefabricated Volumentric Construction (PVC) approach in West Terra @ Bukit Batok, which is constructed in a similar way, although painting and tiling were done on site.
The pre-fabricated concrete bathrooms were piloted in Fernvale Lea, a BTO in Sengkang ready in January 2016. In total, the HDB has implemented such bathrooms in 15 projects, or 14,000 units.
It will install these bathrooms in 60 per cent of the flats launched this year, before rolling them out to all projects by 2019.
Besides unveiling these new methods of construction, the HDB added in a statement that it has introduced new materials that "improve productivity and offer residents a better home".
These include vinyl strip flooring to replace floor tiles in bedrooms, which can be installed easily on-site or off, and also offers better slip resistance. Another example is unplasticised polyvinyl chloride skirting, which replaces the traditional timber one - this is supposedly of better quality and can be installed more quickly.