AbstractThis study aimed to determine the adequacy of Construction Industry Standard (CIS 18:2010) for
manual calculation in Industrialised Building System (IBS) content. In addition, this study
examined the weaknesses and improvements that needed to ensure that the manual calculation of the
IBS system content used by the industry is according to the current needs. Literature research,
focus groups and interviews were used to collect the data. The focus group involved 43 respondents
with two series of workshop and 32 experts for validation workshop. The findings show that, there
are several requirements for the new IBS methods and these manuals need to be reviewed after 5
years of use. As a result of the focus group discussion, they have proposed the addition of several
elements such as Building Modelling Information (BIM), Prefabricated Prefinished Volumetric
Construction (PPVC), Prefab Bathroom Unit (PBU) and Prefab-Staircase in the.....