by Brianna Crandall — May 4, 2016 — Green roofs are an ideal way for building owners and facilities managers to lower their heating and cooling costs, provide additional insulation, help manage storm water, and transform an ordinary roof into a nature retreat for tenants. But while the demand for green roofs has steadily increased since 2004, especially in densely populated metropolitan areas, building owners should consider several factors before investing in a green roof for their structure, according to Bade Roofing Co.
David Bade, owner of St. Louis-based Bade, pointed out:
Government entities and large corporations are the primary purchasers of green roofing systems; however, there is a growing trend for green roofs within the condominium, loft, and apartment building high-rise market segments. These owners are looking to convert their less appealing old roofs and patios into lush living spaces.
A large percentage of the green roofs Bade has seen in the St. Louis area have been concentrated primarily in metropolitan areas where a green roof is tied to refurbishing an existing structure. Such was the case in 2014 when Bade Roofing was contracted to install a green roofing system on a historic building being redeveloped in downtown St. Louis.
Bade crews helped install the rooftop garden courtyard on the building’s 5th floor and re-roofed its 6th floor. The green roof boasts views of the Gateway Arch, Busch Stadium, and the Old Courthouse and incorporates three-color concrete pavers, various trees and shrubs, a fescue lawn area, lighting, seating areas, a watering system and a gas fire pit.
Green roof weight
On a green roof retrofit such as the one described above, remember that the existing structure probably was not designed with a green roof in mind, Bade cautions. The components that make up a green roofing system can be very heavy — stone ballasts, pavers, trays, trees, and soil that become saturated after a rain all contribute to the load the roof deck and building itself will have to endure.
Bade recommends that a certified structural engineer analyze the building during the planning of any green roof project.
Roof leaks
Building owners should also consider what happens if there is a leak in the green roof. Unlike a conventional roofing system where the roof is exposed, the waterproofing components of a green roof are often buried underneath the stone ballast, pavers, growing trays, trees, and soil. Bade says an owner and architect need to be aware of repair issues when designing a green build.
“It’s best to use lightweight components; ones that don’t penetrate the roof system, can be easily moved, and don’t interfere with roof drainage,” advised Bade.
Plant roots
When it comes to rooftop vegetation, Bade said, building owners need to remember one very important tip: “The taller a plant grows up, the deeper the roots grow down.” Bade recommends using growing trays, planter boxes, or plants with shallow root systems, since vegetation should not directly contact the roof membrane. “I have seen plants growing in the dirt and debris that collects on roofs and I have actually seen the roots growing down right through the roofing itself,” Bade noted.
Government incentives
Finally, Bade recommends that building owners check with their local governments for green building incentives and funding to assist with construction costs.
Founded in 1954, Bade Roofing is a family-owned-and-operated commercial and industrial roofing specialist. The company also provides comprehensive roof inspections and survey reports, leak finding and repair services, green roof installation, and licensed asbestos roofing removal and abatement.
