There are major efforts carried out by governmental institutions to improve the sustainability of construction projects. One of the most important problems and challenges facing project's sustainability is deterioration of urban and short life time of building. The aim of this study is to identify the main factors affecting the sustainable projects in order to develop a program to evaluate the sustainability and increase the efficiency of construction by re-evaluating the most affecting factors in the sustainability of the projects and identify the obstacles facing implementation of sustainable buildings.
To achieve the research objectives, a questionnaire was designed to gather information from engineers of different specializations in construction sectors. The questionnaire includes eighty nine factors which are the most important factors affecting the sustainability of construction projects through the five stages of the project. Two hundred questionnaire were distributed and only one hundred and nine responded .The data were analysed by using one of a statistical programs SPSS. The analysed results shows that the selecting sustainability material, developing appropriate rates for all project resources carefully, planning maintenance for construction work and following work that was carried out according to the requirements and specifications of contract. These are the most critical factors which help in sustaining construction, whether before or during construction, and making routine and corrective maintenance of the most prominent factors that help to maintain the service life of building and sustaining it after its establishment.
A Program was developed to evaluate the sustainability of construction either before or after construction, in order to increase the efficiency of a sustainable project and maintaining its life span. The output of the program was represented as a degree of sustainability by evaluation during a certain stage or all the stages of a project and re-evaluating the most important elements affecting on sustainability of project, reaching its highest level of sustainability. It is concluded from the program of evaluating sustainability that the degrees of sustainability may varies from one building to another according to the importance, the volume of construction, the period in which the evaluation is done and the faced challenges. The construction sector in