ABSTRACT
The source and nature of output constants used for preparation of construction estimates should be accurate and reliable for the client to have confidence on the prepared estimates. This research is focused on using time study approach to empirically determine the outputs of block laying work items inconstruction industry. The study reviewed BESMM3 and surveyed possible block work items in construction sites. Ten work items were selected from the identified block work items in BESMM3 and construction sites for Physical observations and output measurement. A total of 105 sites were observed in F.C.T., Abuja and Nasarawa state. Data collected were subjected to statistical analysis using both the descriptive and inferential data analysis techniques. The inferential tools adopted were T-test and ANOVA statistics to assess and examine the influence of some selected labour productivity factors on the outputs of the workers observed. The inferential test revealed the following; period of observation, shape of the building and mode of employment significantly affected outputs on the ten work items. The results of the analysis carried out established mean output values per day for: 150mm thick block in foundation (12.85m2); 150mm thick block in superstructure (13.22 m2); 150mm thick block in superstructure overhand (12.47m2); 225mm thick block in foundation (8.90m2); 225mm thick block in superstructure (11.17m2); 225mm thick block in superstructure overhand (9.16m2); 225mm thick block isolated piers in superstructure (5.00m2); 225mm thick block piers in superstructure overhand (4.57m2); 225mm thick block in pit bottom plan > 4 m2 (7.85m2); 225mm thick block in bottom plan < 4 m2 (7.13m2). The study also identified forty-four (44) block work items not captured in BESMM3 and suggested that these work items be incorporated into BESMM3 for productive and cost implication. The research recommended that in compliance to BESMM3, the NIQS in collaboration with NJIC to sponsor a research on determination of labour outputs in all trades as a way to ensure uniformity in output constants. The study therefore finally concludes that SMM takes cognizance of productivity impact associated with labour and it is imperative for reliability and accuracy in block work estimate to empirically determine labour outputs on the basis of work items as stated in BESMM3.