The buildability legislation was implemented in 2001 to raise productivity in the built environment sector and reduce its reliance on construction workers. Projects with a Gross Floor Area (GFA) of 5,000 m2 and above are required to comply with a minimum Buildable Design Score.
In addition to designers delivering more buildable designs upstream, builders must also play their part in adopting more labour-saving construction methods/technologies downstream. As such, projects with GFA of 5,000m2 and above are also required to meet a minimum Constructability Score.
Requirements for Buildable Design Score
The Buildable Design Score measures the potential impact of a building design on labour usage. It facilitates the adoption of less labour-intensive construction methods and promotes greater use of prefabricated, modular and standardised building components.
To promote more labour-efficient designs and technologies such as Design for Manufacturing and Assembly (DfMA), the mandatory minimum Buildable Design Scores (B-scores) have been progressively raised over the years. Refer to the Code of Practice on Buildable Design/Buildability for the minimum Buildable Design Score required for your project.
Requirements for Constructability Score
The Constructability Score measures the adoption level of labour-efficient construction methods and construction processes, such as system formwork and climbable scaffolding.
As with the Buildable Design Scores, the minimum Constructability Score requirements have also been raised over the years. Refer to the Code of Practice on Buildable Design/Buildability for the minimum Constructability Score required for your project.
Enhancements to the Buildability Framework
In Dec 2019, BCA raised the minimum Buildable Design Scores (B-scores) and introduced outcome-based options for larger residential (non-landed) projects with GFA of at least 25,000m2. Following this, larger residential (non-landed) projects are required to adopt suitable Design for Manufacturing and Assembly (DfMA) technologies. The introduction of outcome-based options also provided designers with the flexibility to propose alternative design solutions which could meet productive outcomes as intended by the Buildability requirements.
Together with other levers, such as public sector taking the lead to adopt DfMA technologies in their projects and requiring the adoption of productive technologies such as Prefabricated Bathroom Units (PBU) and Prefabricated Prefinished Volumetric Construction (PPVC) for selected sites under the Government Land Sales (GLS) Programme, the industry has progressively built up capacity and capability in DfMA.
In 2020, the COVID-19 pandemic has disrupted the built environment sector and shown our heavy dependence on manpower. It reaffirms the need for industry transformation through the adoption of technology such as DfMA to reduce our vulnerability to manpower disruptions. Thus, on 28 December 2020, BCA enhanced the buildability framework to:
- Revamp the Buildable Design Appraisal System (BDAS) to integrate DfMA technologies into each work discipline of Structural, Architectural and Mechanical, Electrical and Plumbing (MEP);
- Recalibrate new minimum B-Scores for all development types; and
- Extend outcome-based option to all large development types in lieu of meeting the minimum B-Score
The above changes were announced in the Circular on Enhancements to Code of Practice on Buildability to accelerate adoption of Design for Manufacturing and Assembly (DfMA) technologies issued on 21 December 2020.
For more details on the changes in the Building Control (Buildability and Productivity) Regulations and the Code of Practice on Buildability, 2017 Edition, please refer to the following: