Proceedings of the International Convention of Society of Wood Science and Technology and United Nations Economic Commission for Europe – Timber Committee October 11-14, 2010, Geneva, Switzerland Paper BC-4 1 of 9 Environmental Evaluation of Timber Buildings using Life Cycle Assessment Methodology Caroline D. Frenette, Robert Beauregard, Cécile Bulle and Sylvie Alain INTRODUCTION Over the last decade, the movement towards sustainability has increased the importance of environmental footprint reduction as a design decision criterion. Building construction and operation stresses the environment in several ways, including the depletion of natural resources, waste generation and emission of greenhouse gases. The building industry is known to be an important environmental contributor to green house gas emissions (IPCC 2007), and the ecological impacts of constructed facilities retains the attention of building professionals across the world. Design decisions have a significant influence on the total lifetime environmental footprint of a building. In addition to materials evaluation, the importance of assessing entire buildings is stressed by several factors, such as the relative importance of maintenance and operation impacts. Designers and policy-makers are increasingly seeking scientifically-based information on environmental impacts of constructions. Several environmental assessment tools for buildings have been developed using different approaches, considering various criteria and aggregation techniques (Ding 2008, Haapio and Viitaniemi 2006). Life cycle assessment (LCA) is a relatively new scientific methodology allowing the quantification of environmental impacts of a product over all stages of its life cycle. Work has been done on applying LCA to whole buildings and building components evaluation (Ortiz et al. 2009). Many studies comparing different structural systems with similar thermal performances recognize the lower environmental impact of wood products. The relative contribution of embodied impacts of building materials used during construction and renovation has been recognised as being significant, especially for low energy buildings (Matasci 2006, Blengini and Di Carlo 2010). To facilitate these studies, environmental evaluation of entire buildings using LCA methodology requires extensive work and adaptation. This paper discusses this issue and highlights actual possible research avenues. ENVIRONMENTAL BUILDING EVALUATION Environmental assessment tools for buildings can be grouped into three levels: 1- tools for product comparison, 2- whole building or building component evaluation tools, and 3- whole building assessment frameworks (Trusty 2000).