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Top1. Introduction
Age is associated with various physical disabilities such as limitations related to mobility, hearing, and vision. The number of people in Canada reported to have a disability increased by three-quarters of a million (0.75M) between 2001 and 2006 to reach 4.4M in 2006 (Statistics Canada, 2006). Furthermore, it was reported that 4.4M Canadians living in households have an activity limitation while 3.6M Canadians reported having limitations in their everyday activities due to a physical or psychological condition. In 2010 an estimated 4.8M Canadians were 65 years of age or older; this number is expected to increase and is expected to account for close to 25% of Canada’s population by 2030 (Health Canada, 2011). Because the disability rate is higher for the elderly than for youth, an ageing population will considerably increase the overall disability rate in the population (Statistics Canada, 2001). This requires society to be well-equipped in order to face this social and demographic phenomenon by making changes, often minor, to factors shaping and seriously affecting the daily lives of a large part of the Canadian population without practicing any type of segregation or discrimination against them (Public Health Agency of Canada, 2011). Hence, the Universal Design (UD) concept becomes increasingly relevant since it examines the notions of health, disability, access, remedy, and accommodation in a new perspective of designing, constructing and modifying homes for Canadians (Mace, 1991). However, incorporating the principles of sustainability with UD to attain sustainable universal design (SUD), can support the design and construction of homes that work for people of differing ages and abilities; homes that are healthier and environmentally friendly. Yet, adopting homes that are universal and sustainable requires a detailed evaluation of their costs and benefits to homebuilders and homebuyers, and a comprehensive assessment of the tools used to design and build new homes and to retrofit existing ones in a simple and cost-effective manner. BIM is a concept that enables engineers to design and create virtual models so they can visualize, simulate and evaluate different design alternatives before the physical construction of buildings. To accomplish this, designers use tools to create 3D models wherein associated components are selected from the built-in database, which lacks detailed information about the requirements of SUD. Thus, there is a need to develop detailed lists of all the components needed to implement sustainable universal homes that allow people to age in them, and to evaluate and classify the costs and benefits of adopting such a type of homes. We must investigate the benefits of integrating the concepts of sustainability, universal design, and BIM as a potential strategy for designing, building and remodeling homes for Canadians. Important decisions related to the design of sustainable universal houses are made at the conceptual stage of their lives. This practice does not consider integration between the design and energy analysis processes during early stages and leads to inefficient backtracking to modify the design in order to achieve a set of performance criteria (Schueter et al., 2009). The total life cycle energy of a residential house includes both embodied energy and operating energy (Crowther, 1999). Embodied energy is sequestered in construction materials during all processes of production, on-site construction, and the final demolition and disposal. Operating energy is expended in maintaining the inside environment through processes such as heating and cooling, lighting and operating appliances. Gonzalez and Navarro (2006) believed that construction materials with high embodied energy could possibly result in more carbon dioxide emissions than is found in materials with a low embodied energy. Presently, Building Information Modeling tools help owners and designers make energy related decisions that have a high impact on the house life cycle cost at its early design stage. It is commonly known that BIM tools are very beneficial and their key strength resides in their interoperability with other programs. However, the interoperability between BIM tools and energy analysis software is limited even though new solutions, such as interoperable file formats, have been developed. File formats, such as the Industry Foundation Classes (IFC) and Extensible Markup Language (XML), are currently promoted by various groups in the construction industry. Yet, using BIM tools to design sustainable universal houses necessitates the selection of materials and systems so that their Environmental Impacts (EIs) and embodied energy can be easily evaluated. The common method used to quantify the EIs and embodied energy of the selected materials is Life Cycle Assessment (LCA), which is a concept used to evaluate environmental concerns (Khasreen et al., 2009). Hoff (2008) described Environmental Impacts (EIs) as being the result of the inputs and outputs over a product’s life cycle. For this purpose, designers can use “The Impact Estimator for Buildings,” which is stand-alone software that allows users to model their own custom assembly and envelope configurations, and provides them with the flexibility to modify the design of proposed designs and existing houses. The main objective of this paper is to evaluate the benefits of integrating BIM with LCA, energy analysis, and simulation tools to design sustainable universal houses at the conceptual stage in an attempt to help owners and designers analyze the day lighting, measure the thermal and evaluate the benefits and costs of such type of houses.