The extensible ecological roofing is the least expensive green roofing. In Quebec, one notices more and more the implantation of green roofings on our commercial, industrial, but also on our residential buildings. Such kind of technology can, however, not be applied to older dwellings unless one makes very expensive transformations to existing structures.
This phenomenon of green roofings originated in Germany many years ago, but Quebec is very interested in it now. It is imperative, however, that this technology can adapt itself to our rigorous climates, so that it can survive three winters in order to be considered acceptable, and every green roof is a case of its own. That is the opinion of architect Owen Rose, the president of the Centre d'écologie urbaine de Montréal, and strongly involved in research at this level. He was the keynote speaker at a symposium organized by the SHQ ( the Société d’Habitation du Québec ), on the topic of the green house, which was recently held in Trois-Rivières.
Green roofings, in Montreal and in Quebec City, are more numerous than one may think, in particular on public buildings. There are, for instance, those garden roofs on the Place Bonaventure in Montreal, and that field of fine herbs that is cultivated on the Hôtel Frontenac in Quebec City.
Be careful however, because for these green roofs a quite particular maintenance must be anticipated. However, if the soil is well-chosen, with selected plants, then there are many advantages with this kind of roofing because: it allows to constrain urban heat and periods of smog; it also allows to have better management of streaming water; it protects the lifespan of the roofing; it increases the energy efficiency of the building; it filters atmospheric pollutants; it soundproofs and reduces phonic nuisance, and it improves biodiversity. Finally, a point not to neglect, is the aesthetic side of it which becomes a power of conviction in having someone willing to go ahead with this kind of roofing.
The speaker believes, however, that one must see to it that the construction of green roofs is well managed. This is not done yet in the municipalities of Montreal and elsewhere in Quebec.
In order to encourage green roofing, there is no programme of subsidies yet in Quebec, contrary to other regions such as Toronto and Chicago. Finally, it is interesting to know that all eyes are turned to the Germans who are most ‘avant-gardistes’ in this technology of green roofings, with an experience extending over decades.