On August 9, 2021, the United Nations Intergovernmental Panel on Climate Change (IPCC) released a scathing report detailing the indisputable impacts that human activity have made on the planet—many of them reaching the point of irreversibility within the next generation or two. The most consequential effects come from greenhouse gas emissions, which are responsible for approximately 1.1°C of warming since the latter half of the 19th century, according to the report. Considering that a 1.5ºC warming is projected to occur over the next two decades, and a 2ºC warming puts the planet in danger of heat extremes beyond tolerance thresholds for agriculture and human health, according to the IPCC the time for immediate, rapid, large-scale change is now—right now, in fact.
The World Green Building Council’s 2017 Global Status Report estimates that buildings alone are responsible for nearly 40% of carbon emissions—putting much of the onus for mitigation and remediation of this climate catastrophe on the real estate sector. In fact, there is a certain symbiosis between buildings and the environment: as hotter times get hotter and colder times colder, more energy is needed to keep buildings and their residents comfortable. As weather events become more frequent and intense, buildings must perform more frequent and intense inspections, repairs, and replacements to keep up and keep safe. All of this contributes to the climate crisis.
Fortunately, residential and commercial buildings alike have great options and opportunities for addressing their climate impact—and many have to do with upgrades to their roofs. Such upgrades can be as simple and inexpensive as applying a coating of reflective white paint, or as complex (and costly) as creating a communal roof deck or vegetable garden—but all are considered “green” for environmental purposes. Each project comes with its own potential for energy savings, grants and incentives, quality of life enhancements, revenue generation, community-building, and property value. These must be weighed against engineering and structural concerns (e.g., how much weight can the roof support?), the desires of the residents (perhaps especially those on the top floor), and of course, cost.
Know Your Roof
In embarking on any roof project, the first thing to know is what kind of roof you’re working with. For example, low-rises or individual HOA units with sloped roofs have different options than high-rises with flat roofs. A sloped-roof community might opt for what is known as a “cool roof”—a reflective surface that can be 50ºF less than a typical asphalt roof, according to American Home Contractors, based in Florham Park, New Jersey.
“When making the decision for a cool roof,” says the company’s rep, “it is important to factor in heating degree days—days under 65ºF—and cooling degree days—days over 65ºF. In areas with more cooling degree days, a cool roof is a no-brainer. But even in a state like New Jersey, where heating degree days are more common, a cool roof can still be a benefit, because the heat absorbed by your roof can transfer into your home, causing a need for greater amounts of air conditioning.” A cool roof can reflect up to 80% of the sun’s UV rays, according to American Home Contractors, and is as easy as installing lighter colored or reflective shingles, or having a cool roof coating applied to existing shingles. The Department of Energy estimates that the cost of installing a cool roof is comparable to the cost of installing a traditional roof, while applying coatings to an existing roof surface costs between 20¢ and $1 per square foot, depending on the type of application.