Green roofs bring savings, peace of mind and protection – if installed correctly

Tom CorbettGreen roofs have been sprouting up on residential and commercial buildings across the city, especially since Mayor Richard M. Daley began offering developers who adopt the environmentally friendly technology financial incentives, including higher density levels for their projects.

In fact, Chicago leads the nation in the installation of green roofs, with about 250 sky gardens totaling 2.5 million square feet, according to the city’s Department of Planning and Development.

As a home inspector, I advocate green roofs because they not only help the environment, but they also can protect the buildings that they sit on.

Green roofs are basically engineered gardens whose job is to act as a kind of conduit between the building and the environment. They conserve energy, regulate the building’s temperature and protect the structure from the elements.

Green roofs also can help condo owners save money. How? The vegetation, soil and water of the garden protect the roof’s waterproof layers from damaging ultraviolet rays and the stress of extreme temperature fluctuations. Conventional roofs last up to 20 years, but green roof technology has been known to prolong a roof’s life for up to 40 or 50 years. Just think of the amount of money that could be saved on condo assessments if expensive roof replacements only occurred half as often.

Rooftop gardens also have psychological benefits. When you live and work in a concrete jungle, the soothing environments of sky gardens are wonderful stress-busters.
But if they aren’t installed correctly, they have the potential to cause more stress than they alleviate. Problems arise when developers cut corners in an effort to save money and don’t hire people with the necessary expertise to install rooftop gardens.

Some developers hire landscape architects to design their sky gardens, but don’t retain the architects to actually implement them. Instead, they hand the job over to a regular landscape gardening crew. That’s a mistake because eco gardens are intricately engineered systems of river rock, stone, sand, topsoil and vegetation. They can’t be left to a “hoe-and-grow” crew.

If the roof’s drainage system is inadequate or poorly installed, it can actually collect water and freeze, overloading and damaging the roof. This is a problem that I’ve witnessed in the past year.

Damaged filtration systems can also redirect water into condos, causing mold or mildew, as well as problems with carpeting and hardwood floors.

If you’re shopping for a new home, bear in mind that the cost of replacing a faulty green roof can run from $100,000 to $200,000, not to mention the cost of fixing damage to your condo. Below are some things to watch for, but consult a home inspector or civil engineer for a more exhaustive inspection.

Get a copy of the blueprints for the building and check that the roof was actually installed by a landscape architect.

Make sure that the landscaping is installed at least eight inches below the threshold of the door to the roof. Any closer, and water may seep into the building.

Check whether the developer has installed pieces of metal, called flashing, below the threshold of the rooftop door, extending into the grass or garden. Flashing prevents water from entering the building, so if you don’t see any, look for signs of water damage inside the structure.

Inspect the ceiling of the top-floor condo for cracks or stalactite-like formations. If either is visible, it means that water is getting in through the roof, or perhaps that the structure is undergoing the normal process of moving and settling that all new buildings experience. If it’s the second option, you’re ok. If it’s the first one, you’d better get out your shovel. It will help, given the amount of money you’ll have to fork over to the contractor who has to repair the roof.

Thomas Corbett is president of Tomacor, Inc., a professional property consulting company specializing in commercial and residential property inspections and expert witness work.

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