Basics Of Buildable Design

The 3S Principles of Buildable Design

Standardisation - repetition of grids, sizes of components and connection details

Simplicity - uncomplicated building construction systems and installation details

Single integrated elements - those that combine related components together into a single element that may be prefabricated in the factory and installed on site.

The Buildable Design Appraisal System

The Buildable Design Appraisal System (BDAS) was developed as a means to measure the potential impact of a building design on the usage of labour. The appraisal system results in a buildable design score of the design based on the 3 components of the formula:

Buildable Design Score Formula

Buildable Design Score (BDScore) of Building =

BDScore of Structural System
+
BDScore of Wall System
+
BDScore of Other Buildable Design Features

Please refer to the Code of Practice for details on computation of buildable design score.

The Guide to the Buildable Design Appraisal System (for COP on Buildable Design, September 2005 Issue) is also available for download here.

Constructability Appraisal System

The Constructability Appraisal System

The Constructability Appraisal System (CAS) was developed as a means to measure the potential impact of downstream construction methods and technologies on the productivity at site. The CAS results in a ‘Constructability Score’ of the building works.

The Constructability Score is expressed as: 

Constructability Score of Building Works =

Constructability Score of Structural System
+ Constructability Score of AMEP* System
+ Constructability Score of Good Industry Practices

*AMEP refers to Architectural, Mechanical Electrical and Plumbing

Please refer to the Code of Practice on Buildability, April 2011 issue for details on computation of Constructability Score.

The submission form for Constructability Score can be downloaded here. Submission of the Constructability Score is via Corenet ESS.

For more information on the Industry Briefing on Enhanced Buildability Framework which includes the Constructability Score E-submission Guide, please refer to here.

Constructability Points for System Formwork

System formwork are classified into vertical formwork and horizontal formwork under the Structural Component of the Constructability Appraisal System (CAS). There are 5 bands assigned to both vertical formwork and horizontal formwork. Each band is allocated different points to reflect the relative efficiencies of different system formwork.

The banding of any system formwork is based on productivity assessment outcome. Productivity assessments are conducted by formwork system suppliers or builders and witnessed by BCA.

Disclaimer: The banding of system formwork is for the purpose of allocating Constructability points to the different system formwork based only on assessment of their productivity outcome. They do not represent any form of endorsement, approval or accreditation by BCA for their purchase, lease or use. BCA will update the banding information from time to time when more system formwork have been assessed. BCA reserves the right to raise the productivity assessment standards of system formwork and the corresponding bands upon review and may downgrade any system formwork from its given band if the quality of concrete finish arising from its use is poor.

The following table lists the system formwork which have been assessed and their allocated bands and associated Constructability points:

Note: The productivity bands of the following system formwork have been temporarily suspended pending the outcome of their re-assessments:

Suppliers/builders may request for re-assessment of their listed system formwork within 1 year from the date of the first assessment. BCA will publish the better of the 2 productivity outcomes.

In the event that a particular system formwork has not been assessed on its productivity, the system formwork shall be taken to have the same productivity as system formwork classified under Band 5 and be awarded with the lowest Constructability Points.