Vegetated Green Roofs

Vegetated “green” roofs (VGRs) are increasing in number in North America. It was estimated that there was over 10 million square feet of VGR in the United States alone as of 2017. As the popularity of such roofs increase, so does the information available to designers and specifiers. However, most of these resources are advocates and therefore tend to focus on initial design considerations and less on such long-term factors as on-going care, maintenance, and other long-term costs.

There are many advantages, unique attributes, liabilities, and costs associated with VGR, all of which balance out differently depending on the building type, location, budget, and owner's agenda. It is for this reason that Inspec is neither an advocate nor a critic of VGRs, but rather a resource who can assist the owner in making an informed decision as to whether such a roof is right for him or her. Then, if such a roof is appropriate, Inspec has the credentials and experience to design a VGR that is unique to the client's particular needs.

Inspec has on staff a Licensed Architect who is also a Green Roof Professional. Inspec received a First Place Award from The Roof Consultants Institute for a forensic failure investigation of a Vegetated Roof. Inspec was on the design team of the Target Center Vegetated Roof.

Potential Benefits (Partial List):

• Aesthetic improvement
• Energy efficiency (though not unique to vegetated roofs)
• Fire retardation
• Blocking electromagnetic radiation
• Noise reduction
• Storm water management
• Waste water diversion
• Mitigation of urban heat island effect
• Improved air quality
• Increased ecological biodiversity
• Marketing
• LEED credits for new building construction

Potential Liabilities and Costs (Partial List):

• Specialized design expertise required of roof designer (higher fees)
• Greater number of design consultants may be required (more fees)
• Higher initial construction costs (2.5 to 4 times as much as conventional roofing)
• Higher long-term maintenance costs
• Reduced marketability in private sector for many years to come