Lam, 2004. However, it has adverse effects to environment and through sustainable construction concept; the construction industry can contribute in a positive and proactive manner towards environmental protection .
Causes and effects in Nigeria. However, being a complex, fragmented and schedule driven industry it always facing chronic problems such as low quality and productivity, cost overrun, time overrun, construction waste and others.
Soon, 2007. These overruns are caused from several factors which are very important to uncover for improving the cost performance. Oluwoye and L. Time Delay can be due to one or more reasons including problems of financing and payment for completed works 46, Other statistic states that more than half of all resources 50,-52], poor contract management and shortage of materials consumed globally are used in construction, and 45 per cent of , design changes , weather condition  among energy generated across the world is used to heat, light and others.
Anis and E. Lee and J. A quantitative assessment of the cost and time impact of variation orders on construction projects. Abdul Azis and I.
Vanegas, J. Assaf and S. Sustainability Principles in Construction  environmental degradation, and creating a healthy built The Principles of The Interpretation of Sustainability environment to these criteria .
Sweis, R. Other study  N.
The trend is more severe in C. Questionnaire for the survey was developed based on 35 common factors of cost overrun identified from literature work. Fluctuation of prices of material: His study showed that the percentage of cost overrun in road projects was the highest with the rate of 18.
Potential effects on large mara construction projects due to construction delay. Holm and S.