An integrated electronic commerce (Ecommerce) based construction industry bidding and project management system and methods facilitate managing real estate, development, construction industries, engineering and construction projects by integrating functions (1001), bidding function (1001b), building and construction functions (1001c) and maintenance function (1000d). These functions are coupled via link (2000) to a core technology infrastructure (2002) for providing respectively desired business services. The system help participants to achieve cost efficiencies and performance enhancements.