Frequently Asked Questions

What is a green roof and why should I get one?

A green roof is an extension to a building’s roof that incorporates living plants, a growing medium, drainage layer, root barrier and high-quality waterproofing membrane. Also known as living roofs, vegetated roofs and eco-roofs, green roofs have many noted benefits. They promote biodiversity by introducing a variety of plant species to new habitats and attracting pollinators, birds and insects. Green roofs contribute to stormwater management via the detention and retention of intercepted precipitation. During storm events, green roofs reduce the volume of runoff and attenuate peak flows. Thus, effectively diverting stormwater from wastewater management facilities. Plant evapotranspiration cools ambient air temperatures, reducing building energy consumption and mitigating the urban heat island effect.

As much as we promote green roofs for their many social, environmental and economic benefits, in some cases green roofs are required by law! In Toronto, Chapter 492 of the Toronto Municipal Code mandates green roofs on new buildings with over 2,000 square meters of gross floor area. In order to comply with the municipal bylaw, green roofs must achieve 80% vegetated coverage within three years of planting. Our maintenance team often works with building management to ensure this coverage requirement is achieved.

Are there different types of green roofs? How do I know which type is best for me?

Green roofs are classified as intensive, semi-intensive, and extensive. Extensive green roofs have a lower depth of growing medium (less than 6”) and may require less maintenance and irrigation. Once established, intensive green roofs have a high growing media depth (over 6”). This can support a greater network of biodiverse species and may require more maintenance. Green roofs are further classified by their system type. For example, vegetation can be grown and installed in modules, rolled out in pre-vegetated mats, or composed of loose-laid materials.

The systems we work with differ in terms of growing medium depth, components, and vegetation type. Our project managers will work with you to recommend a system suited to your project needs.

Does a green roof need irrigation?

While most green roofs are designed to be drought-tolerant they do need additional irrigation and attention in the first two years of establishment. Extensive or only sedum-planted green roofs can make due without additional irrigation after the establishment phase and may only need temporary irrigation to see them through the first two years. Intensive green roofs usually have a higher diversity of plants that may not be as drought tolerant as sedum roofs, such as trees, shrubs, flowering perennials and grasses. Intensive green roofs also tend to be more visible and accessible to people. Therefore requiring a permanent suitable irrigation system to keep plants looking healthy. Note that green roof irrigation schedules will be different from landscape irrigation schedules mainly due to soil type, and should be set with the help or consultation of a Green Roof Professional.

Do green roofs need maintenance?

Yes! While established green roofs can be low maintenance, there is no such thing as a maintenance-free roof. Even conventional roofs require periodic checks for damage that can lead to large repair costs down the road. Ongoing maintenance ensures that plants are healthy and the green roof is functioning according to manufacturer guidelines. Common issues that arise on green roofs without regular maintenance are the intrusion of undesirable volunteer species, overgrowth into vegetation-free zones, erosion from wind exposure, and nutrient deficiency.

What services does Ginkgo offer for routine maintenance?

Ginkgo’s services include fertilization as needed, weeding, irrigation, clearing of root-free zones, trimming when required and reports outlining work completed after each visit. During these routine visits, our team also looks for any issues on the roof itself. Issues such as pooling water, broken skylights or damaged flashing/siding and will notify clients through regular reporting. In order to provide services that meet the needs of each green roof, Ginkgo undertakes soil testing annually across a representative sample of sites to assess and address nutrient levels with a fertilizer tailored to the roof. Ginkgo also specializes in large or small vegetation repairs to ensure full coverage and regenerative growth.

How often should my green roof receive maintenance?

Our maintenance operations begin with a site assessment to determine vegetation and system health, followed by a maintenance proposal that is tailored to the needs of the green roof. Depending on the green roof, its plant mix, weed presence, and other factors, we recommend a maintenance package that could range from weekly maintenance to visits every few months.

How much should I budget for green roof maintenance?

Typical costs for an established green roof that has had a maintenance plan in place since installation can be as low as $1- $3 per square meter. In contrast, a roof that has been neglected or is difficult to access can range anywhere from $5- $10 per square meter.

Can a roof have both green roofs and photovoltaic panels?

Yes! Ginkgo Sustainability has worked with a number of integrated PV green roof systems and has found that green roofs and solar panels can share roof space in a mutually beneficial way. Raised PV panels can provide shade for vegetation and result in higher growth rates. In turn when plants evapotranspirate they lower ambient temperatures and help cool the panels and increase their power output. The literature on this topic reinforces our experience with integrated PV green roof systems and has been the focus of a research team at the University of Toronto’s Green Roof Innovation Testing (GRIT) Lab.

Are green roofs eligible for any government funding?

The Eco-Roof Incentive Program is a City of Toronto initiative that supports the construction of green roofs by offering grants to help offset installation and structural assessment costs. Learn more about the Eco-Roof Incentive Program and eligibility here.

Ginkgo can help with green roof grant applications and the permitting process. We are qualified Green Roof Professionals (GRPs) and experienced in this process. Contact us to learn more.

Do you offer design services?

Yes! The Ginkgo team is comprised of Landscape Architects, Botanists, Arborists, and Horticulturalists. These qualifications combined with the hands-on knowledge of best maintenance practices, and extensive experience installing various green roof and living wall systems make for a smooth and successful design-build project.

What is a living wall?

A living wall is a vertical garden for interior and exterior spaces. Components vary by system but typically include an irrigation and lighting system. As well as a variety of plants that are compatible with the site-specific environmental conditions and meet the design preferences of the client. Living walls have noted benefits including improved health, wellness and productivity for building occupants through exposure to biophilic elements. They also contribute to better indoor air quality by actively reducing indoor air contaminants. Air contaminants like particulate matter (PM) and volatile organic compounds (VOCs).

How much does a living wall cost?

Smaller systems (less than 100 sqft) will have the highest per square foot cost. As a general rule, the larger the area the lower the cost per square foot. There are many variables that can affect the price of the living wall, including system type and design preferences. Ginkgo works with clients to accommodate budgetary restrictions wherever possible; please contact us for a customized quote.

Do living walls need maintenance?

To ensure plants are healthy and that the living wall is providing a full suite of benefits, ongoing maintenance is essential. Our maintenance services include trimming and replacing plants within a set budget, troubleshooting operational issues, fertilizing, and pest management. These visits typically occur at a monthly rate but can be more or less frequent depending on the health of the wall and client preferences. Maintenance costs vary based on the type of system, size and access, please contact us for a customized maintenance quote.

What does my building require to have a living wall system?

The living wall systems we work with incorporate irrigation systems and lighting that reduce the need for manual plant care. While requirements vary according to the system chosen, we typically ask for a water connection and electrical outlet nearby. We also require a load-bearing wall, with specific load requirements varying by system type.

What is Mossart? Is it alive?

Mossart is made from moss that has been preserved, coloured, and fitted in a pattern or design. Several types of moss can be used, including reindeer, sheet, and pole moss, each preserved using all-natural oils and dyes. Mossart can be designed to incorporate a logo or pattern. Therefore making it a popular choice for offices looking to add biophilic design elements to their workspace. While the moss is no longer living, it is real moss. Preserved moss requires no maintenance, and has a lifetime of about 10 years. Costs vary according to the size of the piece and the complexity of the design, please contact us for a customized quote.

How do green roofs and living walls contribute to green building certifications?

Incorporating biophilic elements into built environments provides benefits that have been recognized by major green building standards around the world. Within the City of Toronto, Tier 1 of the Toronto Green Standard requires that applicable new development comply with the city’s Green Roof Bylaw. All other new buildings must implement roof measures to mitigate the urban heat island effect, with one option being 50% green roof coverage.

In addition to fulfilling green roof bylaw requirements within the City of Toronto, green roofs contribute to many credit categories within LEED v4, BD+C New Construction. In the Sustainable Sites category, green roofs contribute a maximum of seven points towards certification, which requires at least 40 points. These credit categories are: Protect and Restore Habitat, Open Space, Rainwater Management, and Heat Island Reduction. Ginkgo’s services are also compatible with the WELL Building Standard v1. A standard that focuses on achieving measurable improvements on occupants’ health and wellness through building design. Incorporating biophilia into the building’s design through living walls and accessible rooftop gardens are optional optimizations that contribute to certification requirements.

How do I learn more?

Contact us to learn more about our green roof and living wall services and experience. Our team can help at any stage in the process, whether it’s design, consulting, project management, installation or maintenance services. Give us a call at 1-800-620-3340, or send us a message at