Investigation Into Estimation of Building Projects Variation Contract Period

Abstract

In Kenya, the construction industry has a big contribution to national economic growth and therefore the improvement in efficiencies of the industry through of effectiveness in timelines that would certainly contribute to an overall cost savings for the industry and the country as a whole. The aim of parties in a given construction project is to obtain a constructed facility within the specified time, budget and specifications, Kivaa, (2000). In developed countries of United States of America, United Kingdom and Germany, Mobbs (1982) document that ‘construction time’ is well achieved as it is well planned at the commencement of a project. In a developing country case in point Nigeria, the performance of the construction industry time wise is poor leading to increased costs, Odeyinka and Yusif (1997). It was also found out at that seven out of ten projects surveyed had delays in their execution. Documentation of quality and budget as a measure of success in construction has been documented by Chan and Kumaraswamy (1993) to show that delivery of projects within time, budget and expected quality standard as specified by the client is an index of for measuring successful project delivery. However, project variations aspects have been found to be a major contributing factor to non delivery of on time, cost and quality. Variations however do occur on the project and a cost is factored at the beginning of the project but time is not. Contract time is thus extends in the project and the objective of this project to find out how time is calculated at the commencement of project and how the time for carrying out the variations is calculated and by who and of those methods are effective and to satisfaction of the parties involved. The study employed descriptive survey design while the target population consisted of developers, consultants and construction site managers of construction projects in Nairobi County. The study relied on primary data source and used purposive sampling technique. The study generated qualitative and quantitative data in which quantitative data was coded and entered into Statistical Packages for Social Scientists (SPSS Version 17.0) for analysis using descriptive statistics. The conclusions of the study were that estimation of project time is done by the consultant whereas estimation of time for carrying out variation work is done by the contractor. A combination of mathematical and non-mathematical methods are used but non-mathematical is the most popular method used in calculating the time for projects and time for carrying out variation work. Mathematical methods, like the Bromilow’s Time Cost (BTC) model is rarely applied in the Kenyan construction industry as a model of estimating project construction time. Many projects experience extensive delays thus exceed initial set time. This leads to impairing the economic feasibility of capital projects and extensive delays provide ripe grounds for costly disputes and claims. According to the contractors and project supervisors, errors and omissions in design are a major cause of project variations that lead to delays as well as unavailability of new equipment introduced in variation since procurement problems affect the project completion, while owners ranked delays decision making process as hindering subsequent construction activities. Delays were noted to occur due to external factor like change in government, regulation and location. The study recommended Contract Variation issued should always be accompanied by variation period and that the Project Managers should always cater for impacts which cause extension of time and/or increase in cost are frequent occurrences in project construction. At the commencement, contractors should regularly try to identify and to bring to the attention of the client project risks such as an ill defined scope in the early stages (tender clarification meetings) of a project. Whereas there is use of mathematical and non-mathematical methods of estimating time, the current methods applied do not satisfactorily achieve the expectations and it is recommended as an areas of further research that a model of estimating time should be developed to act as a guide the for the Kenyan construction industry.