Because of their bespoke nature, construction projects are susceptible to variations irrespective of type, size and complexity. The effects of these variations are significant and may include cost and time overrun, productivity, and waste issues at the minimum. Although variations have been widely researched, investigations into the relationship between the significant causes of variations and their effects have not. This study also considers control measures that could minimize variations in residential building projects, where significant variations are happening in the Sri Lankan construction industry. A questionnaire survey was administered to study participants with the objective of identifying significant causes and effects of variations on residential building projects. The participants were professionals across industry groups such as clients, consultants, and contractors who deal with variations on Sri Lankan construction projects. The study found that change in designs or project scope by owners or design consultants were due to owners’ financial problems, errors and omissions in design, conflicts between contract documents, inadequate working drawing details, lack of coordination by consultants, differing site conditions for contractors, unforeseen problems and weather conditions. Cost and time overruns are subsequent effects of those variations. The study suggests that variations could be minimized by adopting control measures that are appropriate for both the design and construction stage.
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