Green Roofs in Healthcare: Fundamentals for Facility Managers

November 19, 2012
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St. Elizabeth Hospital, part of the Affinity Health System, a faith-based regional healthcare network, has two green roofs, including one here at its cancer center. Photo credit: LiveRoof and The Boldt Co. This 3,000-square-foot green roof was installed in August 2011 and creates a healing garden for the cancer center. Photo credit: LiveRoof and The Boldt Co. St. Elizabeth Hospital's Heart, Lung and Vascular Center’s 4,125-square-foot green roof was completed in September 2009. Photo credit: LiveRoof and St. Elizabeth Hospital.
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If a hospital or other healthcare facility has yet to undertake a green roof project, it’s likely they‘ll do so sooner rather than later.

For many healthcare facilities, building projects will require green roofs. When there is little space for stormwater mitigation features at ground level, green roofs are often the most practical approach to moderate the volume and velocity of run-off. Especially on urban campuses with limited open space for expansion, stormwater management regulations can make green roofs essential as the first line of defense.

As more and more healthcare organizations pursue U.S. Green Building Council LEED certification for construction projects, green roofs present another benefit thanks to their contribution to LEED credits in at least a dozen categories.

Outside of green certification, environmental responsibility in general has become a critical element in meeting the expectations of the patients and the communities we serve. Commitment to sustainability and green healthcare has emerged as a core value featured prominently in many hospitals’ mission statements, and green roofs and green walls provide a visible manifestation of this commitment.

In addition, research suggests that patients who have a view of green space have lower levels of stress and anxiety, and recover more quickly, meaning green spaces can serve as therapeutic environments as well.

As healthcare facilities plan green roof projects, a basic set of considerations is fundamental.

Roof load
The weight the roof can support in the location where the green roof is to be installed must be considered first.  Green roofs generally weigh 15 pounds to 50 pounds per square foot, depending on the depth and quantity of the planting medium.

Thus, much depends on the load. This tends to be more of an issue with the renovation of older buildings than with new construction.

Location visibility
Will the green roof be visible? If it won’t seen, the green roof can be planned for utilitarian benefits. If the area will be visible, then the green roof can (and should) be planned as an extension of the facility’s landscape architecture to enhance the patient experience.

Access and amenities
If the green roof is visible, it’s also important to consider whether it can be made accessible. It’s becoming more common for green roof projects to feature access from building interiors. More green roofs now incorporate walkways, patios, and seating that enable them to serve as gardens.

The decision to facilitate access will, in turn, affect every other element of green roof project planning.

Water for irrigation
Different climates impose different requirements. In most temperate regions of the country, such as the Upper Midwest, supplemental irrigation is seldom essential if plant selection is correct. However, as little as one inch of irrigation per month during the hot season is generally sufficient to keep plants hydrated and healthy.

That reduces weed encroachment, makes maintenance easier and less costly, and serves to maximize the shading and insulation of a green roof. In the Southwest and West (including California), irrigation is essential.

Type of green roof
There are different types of green roof systems. The basic options are plant-in-place on the roof and modular, with modular containers of plants delivered to the roof.

Not all modular systems are the same. Modules designed to integrate the soil across the installation establish a green roof as a functioning ecosystem and foster sustainable growth. In addition, some modular systems are delivered with full-grown plants.

Installing a green roof with plants that are already flourishing provides immediate and more reliable results and reduces maintenance requirements.

Vendor selection
Regional horticultural expertise is an important factor in system and vendor selection. Understanding plant biology and what plants are going to work for a particular project (given the region, location, and microclimate of the roof) goes a long way toward determining the success of a green roof.

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