Welcome!
Today I’m sharing one of my recent blogs from my site Urbaneer.com that focuses on the intersection of sustainability and housing. Being sustainable is not an all-or-nothing approach. From a housing and design standpoint, it’s about identifying those environmentally-conscious practices and habits that you can realistically adopt and maintain over time. That’s the key to shrinking your footprint.
In this piece, I’m discussing one practice in particular – the green roof!
Read on!
From finishes to floorplans to construction, sustainability is something that homeowners are prioritizing. It can be hard to balance sustainability with style – or is it? I‘ve written about sustainability, housing, and home in my Healthy Home series on Urbaneer.com. Check it out for inspiration.
One eco-friendly way to greenify your home – quite literally – is with a green roof. I applaud the increasing number of homeowners (and builders) who are embracing this practice and its many proven benefits, including a reduction in overall energy consumption.
This article in Landscape Ontario shares that since 2009 “more than 1000 green roofs have been constructed thus far, significantly reducing energy consumption by an estimated 2,200 megawatt-hours per year helping to avert 416 tonnes of greenhouse gas emissions annually. The green roofs have also diverted over 18 million litres of stormwater annually.” Wow!
Curious about how you might contribute to the City’s sustainability with a green roof of your own? Read on!
What Is A Green Roof?
A green roof is an extension of an existing roof system, with the added features of high-quality and extensive waterproof membranes (for obvious reasons), irrigation, drainage, root barrier, filter cloth, growing medium and, of course, vegetation. The levels of the green roof depend on the complexity of the vegetative system, as well as access. You may or may not have all of these layers within your green roof.
They can be either extensive (lower maintenance, less plant matter and less soil depth) or intensive (almost like having a park on a roof, with diverse plant life, trees and more).
They can be built modularly (i.e. with prepared, interlocking kits) or can be constructed piece by piece.
Green roofs can function in the winter, but if that is the plan, it is recommended to choose vegetation that suits the local climate. Theoretically, it would still provide an insular effect.
How Does a Green Roof Work And What Are The Benefits?
Vegetation on a green roof captures moisture from precipitation and dew. It evaporates and effectively sends cooled air into the atmosphere. This simple, but powerful cycle has a profound effect on the atmosphere on several levels.
• Diverts stormwater
One of the biggest, most measurable benefits of green roofs is how they aid in the diversion of stormwater.
They help divert stormwater away from the city water supply by retaining up to 70-90 percent of precipitation in the spring/summer/fall, and up to 30-40 percent of precipitation in the winter. They naturally filter water, making it cleaner and controlling the flow into stormwater sewers.
• Lowers urban thermal effects
This is especially critical in urban areas, where, thanks to climate change, temperatures are consistently rising. Urban areas are prone to heat-related events that are troublesome on a couple of fronts:
1- typically there is less vegetation and tree canopies in urban areas to naturally cool a city and
2- populations are concentrated in urban areas, making more people more vulnerable to these heat events and the health risks that are associated with them.
Green roofs help to combat that in real-time.
• Creates ecosystem
Plant matter and greenery create a localized ecosystem for native plants, animals, insects and birds to flourish, an important role in an urban area, where other opportunities might be limited.
• Improves aesthetics
There are also the aesthetic benefits of the extra greenery. One of the biggest trends in home design now is health and wellness, in part because of the known benefits of connecting with and immersing in nature. And on top of that, greenery just looks good and creates calm.
• Improves air quality
The cycle of evaporation plays a role in naturally filtering the air, offering better, cleaner air, right at home.
• Saves energy (costs)
There are economic benefits as well, in terms of energy reduction. Green roofs also add a layer of insulation, so represent cost-savings for homeowners in terms of energy usage.
A green roof may mean that you need to repair or replace your roof less often, so there are cost savings there too.
• Other benefits…
They can also play a role in fire retardation, and in noise reduction, an important part in combatting noise pollution, an issue in urban centres, which I explored in this recent post Dear Urbaneer: Can I Combat Noise Pollution Through Design?
The Downside Of A Green Roof
There is a potential downside with a green roof: they tend to be more expensive at the outset than a traditional roof.
However, as with several sustainable housing options, an initial investment often means that you can recoup these costs over time with energy savings, as is the case with green roofs.
Installation & Design Tips For A Green Roof
Thinking about installing a green roof? The first criteria include looking at the slope of your roof.
Generally, suitably flat roofs can be modified to be a green roof.
Ideally, the slope would be no more than 20-30 degrees, to accommodate the necessary waterproofing and soil, topped with vegetation.
Another consideration is how fortified your roof is, as it may require additional structural support. The roof needs to be able to support all elements that are installed upon it when dry, but also when wet, which can create significant additional weight.
In terms of maintenance, the approach needs to be like a regular garden-, with weeding and other regular tasks. The green roof should be easily accessible for this reason.
Depending on maintenance needs, you may need to consider access to electrical and plumbing.
Green roofs are not all or nothing as well. You can dedicate a portion of your roof to being green.
Toronto & Green Roofs
Toronto was the first city in North America to adopt a bylaw to allow green roofs, back in 2009. Incidentally, green roofs are very popular in Europe, and have been for some time, but adoption was much slower in North America.
A study conducted in 2006 by Ryerson University, commissioned by the city of Toronto, found that the implementation of green roofs on a larger scale would offer numerous economic and environmental benefits to the city.
The bylaw was introduced as part of a larger plan to introduce more eco-friendly and sustainable practices into new construction.
Simply, commercial, residential and others over a certain size were required to have a component of green roof.
For new commercial, institutional, and residential development with a minimum gross floor area of 2,000 m², or for new additions in the same categories where the addition is greater than 2,000 m², are required to have a green roof.
In addition to mandating the inclusion of green roofs, the city has set out standards as part of the bylaw to make sure that construction is properly adhered to.
Here is the background on the study and implementation of Toronto’s green roof strategy.
As an urbanite, advocate for eco-friendly housing and construction, and realtor all in one, I have a unique perspective to share and assistance to offer on your housing journey. I’m here to help!
Thanks for reading!
~Steven
