Influence de la phase d’usage dans les enjeux de la rénovation de bâtiments résidentiels écologiques : vers une approche diachronique

In North America, construction industry design practices are linked to varied and important environmental, economic, and social concerns. Conceptual trends, like the industrialization of construction, green building, the diachronic approach, and spatial rationalization have proposed to address these issues. Synchronic housing design, still based only on present-day needs, generates static buildings that cannot accommodate needs that evolve over time. Furthermore, during the use phase, which reveals itself as the most costly in terms of energy, water, materials consumption, and waste generation, static buildings may undergo various renovations that are profoundly deleterious, both to the environment and the household’s economic situation.  From a perspective that seeks to operationalize sustainable development, the research problem concerns the consideration of the use phase in the housing design process. In order instead to foster diachronic design, fifty-five residential renovation projects were analyzed and compared in order to describe the nature and intensity of their interventions. A review of before/after renovation plans allowed quantification of intervention intensity and highlighted certain trends and recurrences among current practices.  In order to determine if green building can respond to contemporary environmental issues in housing, a content analysis of strategies proposed by three certification programs used in North America—BOMA-BESt®, LEED®, and Living Building ChallengeTM—is conducted. Classification of these strategies reveals the distribution of concerns regarding building, systems, and user. An analysis shows, generally, that considerations seem consistent with the impacts associated with housing. An examination focused on the content and objectives of those design strategies which consider the user yields the emergence of two thematic clusters: five potential sources of impacts (energy, water, materials, waste, and indoor environment) and four themes linked to the design strategies’ objectives and purposes (maintenance and monitoring; awareness and training; modeling and metering; behaviour and habit).  Discussion permitted the formulation of ecological design criteria, such as disassembly, updatability, and accessibility, to allow for housing that accommodates occupants’ changing needs. Recommendations are proposed, such as the need for better consideration of the user phase in order to make it more consistent with the impacts it generates. Other suggestions call for making building performance more concrete by encouraging the involvement, commitment, accountability, and empowerment of occupants. Finally, it seems that particular changes in certification programs and legislation could encourage the emergence of a new, much-needed vision for total floor area reduction. All these opportunities for improvement seek to lead the sector toward a more holistic approach and to improve significantly the environmental, economic, and social implications of housing.

Keyphrases: Ecodesign, Housing, Diachronic design, Use phase, Environmental impact