Prefabricated bathrooms, units for all Singapore new flats by 2019

THE Housing Development Board (HDB) says it will improve construction productivity through a greater use of prefabricated units that are assembled off-site but that can be installed on-site.

This would drive HDB's construction productivity on a larger scale, setting it on track to achieve a productivity improvement of 25 per cent by 2020, compared with 2010.

One of the initiatives is to expand the use of prefabricated bathroom units (PBU).

The HDB on Wednesday said that it would implement PBUs in 60 per cent of the flats launched in 2017, before extending this to all projects launched by 2019.

It first piloted the concrete PBU in Fernvale Lea, a Build-To-Order (BTO) project in Sengkang, which completed in January 2016. So far, the HDB has implemented the PBU in 15 BTO projects involving some 14,000 units.

Concurrently, the HDB would also adopt the prefabricated prefinished volumetric construction (PPVC) method in 35 per cent of new public housing projects by 2019.

The move is a departure from the conventional approach where workers need to work on the finishes at the construction site.

"This method involves constructing and assembling 3-dimensional (3D) prefabricated modular units with finishes in a controlled factory environment. At the factory, the 3D volumetric components are combined in different configurations (including bedrooms, living room, household shelter and kitchen) to create different flat layouts, and pre-fitted with floor and wall finishes, window frames and a preliminary coat of paint, before being transported to the construction site for installation," said the HDB.

The PPVC method was piloted in Valley Spring @ Yishun, where construction for 824 BTO units started in March 2017.

A key thrust of HDB's productivity drive has been the adoption of precast technology since the 1980s. To date, up to 70 per cent of a typical HDB block's concrete structure is constructed using the prefabrication method.

Besides the adoption of prefabrication technology, the HDB also taps technological innovations such as advanced 3D modelling technology Building Information Modelling (BIM) and Virtual Design & Construction (VDC).

To date, about 130 projects have been designed using BIM.

The use of VDC helps designers and contractors as they spend less time interpreting the 2D technical drawings, in turn cutting misinterpretation.