Vegetated green roof systems for residential and commercial properties in Greater Montreal. Sustainable roofing that manages stormwater, reduces energy use, and improves urban air quality.
Green roofs, also called vegetated roofs or living roofs, are roofing systems that support a layer of plants growing in engineered soil media over a waterproof membrane. They have been gaining popularity in Montreal as property owners and municipalities recognize their environmental and practical benefits. Montreal's urban heat island effect, stormwater management challenges, and growing emphasis on sustainability have made green roofs an increasingly attractive option for both new construction and retrofit projects.
There are two main categories of green roof: extensive and intensive. Extensive green roofs use a shallow growing medium (typically 7 to 15 centimeters deep) planted with low-maintenance species such as sedum, grasses, and other drought-tolerant plants. They are lightweight, require minimal maintenance once established, and are suitable for most flat roof structures without major reinforcement. Intensive green roofs use deeper soil (30 centimeters or more) and can support a wider range of plants including shrubs, perennials, and even small trees. They function more like rooftop gardens but require significantly more structural support and ongoing maintenance.
The benefits of green roofing in Quebec are substantial. Green roofs absorb and retain stormwater, reducing the volume and velocity of runoff that enters the municipal drainage system during heavy rain. They provide natural insulation that reduces both heating and cooling energy costs. The soil and plant layer protects the underlying waterproof membrane from UV degradation, temperature extremes, and physical damage, which can double the membrane's service life. Green roofs also reduce the urban heat island effect by replacing dark, heat-absorbing roof surfaces with evaporative, cooling vegetation.
Our green roof installation process begins with a structural assessment to verify the building can support the additional weight of soil, plants, drainage layers, and retained water. We then install a high-performance waterproof membrane (typically a two-ply modified bitumen or single-ply system), followed by a root barrier, drainage layer, filter fabric, engineered growing medium, and finally the plant material. Each layer serves a specific function, and proper integration between layers is essential for long-term performance. We select plant species that are proven to thrive in Quebec's climate, including native sedums and hardy perennials that tolerate winter cold, summer heat, wind exposure, and the limited soil depth of extensive systems.
Why this service
Stormwater retention reduces drainage system load
Natural insulation cuts heating and cooling costs
Protects the membrane and extends roof life
Reduces urban heat island effect
Improves air quality and urban biodiversity
Potential tax incentives and rebate programs
FAQ for this service
A structural assessment is the first step. Extensive green roofs add approximately 60 to 150 kilograms per square meter when fully saturated, which many flat roof structures can handle with little or no modification. Intensive green roofs are heavier and may require structural reinforcement. We evaluate your building before recommending a system.
Yes. Green roofs in Quebec go dormant in winter under snow cover. The soil and snow layers actually provide additional insulation to the building. The plants selected for Quebec green roofs are cold-hardy species that survive winter and regrow in spring. The waterproof membrane underneath continues to function regardless of season.
Extensive green roofs need minimal maintenance: typically two to three visits per year for weeding, inspection of drains, and occasional fertilization during the establishment period. Intensive green roofs require more regular maintenance similar to a ground-level garden, including watering, pruning, and seasonal planting.
No. Green roofs retain a portion of rainfall but not all of it. The drainage layer underneath the growing medium collects excess water and directs it to roof drains or scuppers. Proper drainage design is essential to prevent waterlogging of the soil and excessive weight on the structure.
Montreal and some boroughs have offered incentive programs for green roof installation as part of stormwater management and urban greening initiatives. Program availability and terms change over time. We recommend checking with your borough and with Hydro-Quebec for current programs at the time of your project.