With the City of Toronto’s goal to reach net zero by 2050, apartment building owners should explore building sustainability options. Here, we look at green roofing, cool roofs, and solar roof systems as three viable eco-friendly roofing solutions for apartment building restoration.
Green Roof Systems
Green roof systems consist of drainage systems, protective waterproof membranes, and growing mediums to support an assortment of lightweight plants. As a result, they create a unique aesthetic, while reducing what is projected to be 65.51% in HVAC consumption by 2100.
Adding to their appeal, Toronto’s Eco-Roof Incentive Program contributes up to $100 per m² in grant money for eligible green roof installations.
Pros of green roofs for apartments:
- Reduced heating and cooling costs
- Reduced greenhouse gas (GHGs) emissions
- Protects the flat roof membrane to extend life
- Reduced risk of flooded basements related to sewer overload and local waterway pollution
- Can be used to grow food for the community and/or as a garden rooftop amenity
- Reduced noise
- Aesthetically interesting
Cons of green roofs:
- Grants are limited to buildings with a gross floor area of less than 2,000 m²
- If not a solid flat roof, requires additional supports to manage the heavier load, adding to costs
- Higher maintenance to tend to the garden if not managed by tenants
Cool Roofing Infographic
A cool roof coating reflects the sun’s UV rays, redirecting radiation away from the surface to help reduce interior temperatures. As a result, buildings without air conditioning can help maintain a cooler, constant temperature for tenant comfort.
It is projected that cool roofs will reduce overall HVAC consumption by up to 71.72% by 2100. Cool roofs are also included in the City’s grant program.
The type of coating impacts the roof’s reflective properties. For example, white roof coatings reflect up to 80% of the sun’s rays, while darker pigmented coatings only reflect up to 20%. An excellent option for asphalt flat roofs is aluminum flake coatings that reflect 50% to 70% of solar heat.
Pros of cool roofing systems for apartment buildings:
- Some costs might be covered under the City’s grant program
- Reduced cooling bills
- Increased AC longevity
- Reduced maintenance costs
- Reduced GHGs
- Peak energy savings and grid stability
Cons of cool roofing systems:
- More expensive than conventional roofing
- Not as attractive as conventional roofing
- Can make the building colder in the winter, potentially offsetting summer AC savings
Solar Photovoltaic (PV) System
Solar photovoltaic (PV) panels use solar cells to capture the photons in sunlight creating a “photovoltaic” effect that converts the energy into electricity. It takes between 15 to 30 panels to generate 500 to 1000 watts of solar PV capacity for a small to average sized apartment building.
In this instance, a NYC apartment building’s 5,000 square foot solar panel system reduced energy consumption in common areas by 35%. A Maryland 12-story, 310-unit apartment building’s 122-kilowatt solar system realized a 100% after-tax payback in year one. Energy consumption was reduced in common spaces and enough electricity was produced to generate a revenue stream through net-metering.
Pros of PV panels:
- Reduced energy costs
- Clean, sustainable source of energy
- 25 to 30-year lifespan
- Eventually creates a revenue stream when interconnected with the electrical grid
- Energy independence during high demand times or power outages
Cons of PV panels:
- No government incentives to offset expensive upfront costs
- Not worth the investment in buildings where tenants pay their own electricity costs
- Not as effective for common areas such as pools or laundry rooms where a UV-based solar water heater system makes more sense
- Potential weight issues that require structural reinforcements
- The inverter device requires interior space
- Improper installation can lead to water and stress-related problems
- Technology advancements can outdate panels in as little as five years
Although these roofing systems are not suited to every apartment building restoration project, they offer inspiration to include eco-friendly solutions that improve your community.
At WellDone Inc., we are committed to improving the construction process, incorporating various innovations to improve efficiencies, reduce risk, and maintain cost efficiency. Reach out to our team today.