In the past two decades, the globalization of financial markets and multinational trade has intensified internationally, and become increasingly competitive. In the construction industry, critical changes are initiated to reduce operating costs for achieving sustainable operation. Conventional cost pricing for building projects no longer apply as energy shortage and environmental pollution are new challenges faced by construction companies. Many countries have attempted to solve the CO2 emission problems by levying a carbon tax, which leads to a higher cost for construction companies. Therefore, this study aims to adopt life cycle assessment (LCA) in order to assess CO2 emission costs and apply a mathematical programming approach to allocate limited resources to maximize profits for construction companies. (C) 2011 Elsevier Ltd. All rights reserved.