Singapore’s quality of pre-fab flats likely to get better over time
SINGAPORE: Pre-fabricating rooms and bathrooms off-site promises not only manpower savings and faster assembly, but also better quality for HDB home owners.
But the announcement this week that Singapore’s Housing Board is targeting the use of more pre-fabricated units for launches from 2019 onwards has left some home owners wondering if the construction method will live up to expectations.
Housewife Dion Lim, 38, for one, is unhappy with the bathrooms in her Fernvale Lea flat – the first build-to-order project to feature pre-fabricated bathroom units.
The Sengkang project was completed in January last year. Since then, pre-fabricated bathrooms have been installed in about 14,000 units over 15 projects islandwide.
Lim says that problems included uneven tiles, loose fittings and rusty doors. It is not clear if these are necessarily due to the bathroom being pre-fabricated, but she says: “I thought that these being prepared in a factory meant that there wouldn’t be these problems.”
She later either rectified them on her own or ignored them.
Installing the Prefabricated Prefinished Volumetric Construction (PPVC) rooms and bathrooms will improve project productivity – the amount of floor area completed per man day – by 50% and 10% respectively, a HDB spokesman said. The method will cut down on the manpower needed in the construction industry, which has long been reliant on foreign workers.
The move is part of the HDB’s drive to improve its productivity by 25% in 2020, compared to 2010.
Says a HDB spokesman: “As contractors become familiar with PPVC construction, we will try to shorten the construction time.”
From 2019, all the rooms in onethird 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.
Speaking at the annual HDB Awards Wednesday night, Singapore’s 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% for the prefabricated bathrooms and 8% for the PPVC rooms per project, though these costs are expected to come down over time.
The technology used to make pre-fabricated units has improved over the years, says Nanyang Technological University engineering professor Robert Tiong.
“Traditionally, pre-fab items were fitted after the building was completed. Now, all the pre-fab units, such as toilets, can be assembled at the same factory with the same pool of labour and expertise, while saving on time, logistics and transportation.”
“It will be easier to manage and ensure good quality, since the inspection can be done at the factory as soon as the unit is completed.”
At the same time, said BHCC Construction quantity surveyor Pan Zhi Hua, quality will improve as those in the industry get more accustomed to the new methods. Her company has not yet used the PPVC method – where entire rooms are constructed fitted with flooring, wall finishes, window frames and paint in a factory, before being transported to the construction site – but it has several upcoming projects where the method will be used.
“After two or three projects, we’ll have the experience to install all these extra efficiently and properly,” she says.
As for the long standing complaint that pre-fabricated units, with their blocky, modular designs, may make for boring buildings, Prof Tiong says a combination of new building materials and methods can help to spice things up.
Architect Calvin Chua says HDB’s adoption of the PPVC method, coupled with last week’s news that structural walls in future flats could be pushed to the side, will give home owners a “flexible empty shell to customise their living spaces”.
HDB also promised better homes with new materials. 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 traditional timber ones. The latter are supposed to be of better quality and can be installed more quickly, says HDB.