The Barbara Truland Butz Healing Garden, a rooftop green space that sits above Shady Grove Adventist Hospital in Rockville, Md., is adjacent to a cancer care unit and visible from 24 private patient rooms and a nursing station. The design is a Zen garden and features a concentric water feature, IPE decking with a substructure of southern yellow pine, slate-faced pavers with custom radial edges and donator engravings, Eastern red cedar pergolas and teak benches.
Credit: Oasis design group

Shady Grove Adventist Hospital in Rockville, Md., wanted to transform a roof into a healing garden to illustrate the hospital's belief in holistic healing and environmental stewardship. The Hospital hired Oasis Design Group, a landscape architecture, master planning and urban design firm in Baltimore, Md., to lead the garden design.

Oasis Design Group (Oasis) managed consultants to retrofit the existing roof and led discussions regarding all the technical aspects of the design. Oasis also developed easy-to-understand visual design graphics that the hospital used to solicit $1.4 million in donations, which funded 100 percent of the construction costs for what became the Barbara Truland Butz Healing Garden.

Today, the garden is directly adjacent to the fourth floor inpatient cancer care unit and visible from the 24 private patient rooms and a nursing station in the unit. The garden serves as a central green space and an extension of the interior function of the hospital to encourage healing.

Two types of roof assemblies typically accommodate green roofs: Protected membrane roof assemblies place insulation above the polystyrene waterproofing membrane, often referred to as inverted roof membrane assemblies (IRMA), whereas conventional roof assemblies place the insulation below the membrane. At Sandy Grove, an IRMA assembly was put in place prior to the start of the garden installation.
Credit: Jane Luce

Design Collaboration
During preliminary planning meetings with the hospital, Oasis espoused the benefits of rooftop healing gardens and was instrumental in the project's conceptualization. From the first planning and design meetings with the hospital through construction to the grand opening of the garden, Oasis provided project leadership.

Oasis led the design and collaborated with the architect and structural engineer on retrofits to the roof to accommodate the garden. Fortunately, during the initial design of the building a few years prior, the architects and the hospital planned for an eventual garden being built in its location, so modifications to the structure were minimal.

The garden's design provides a variety of seating types and locations, and includes movable tables and chairs for personalization as seen in the Zen meditation area. A faux streambed, created from reclaimed roof ballast, runs through the meditation area and ends with a small bubbler fountain (not pictured) located within the garden's outer circle. Tree plantings include creeping juniper "Mother Lode,' lodgepole pine "Chief Joseph,' and Japanese red pines.
Credit: Jane Luce

Oasis met in person with the hospital's surgeons and other staff about the project; many were concerned with or opposed to two separate water features in the proposal, because they would be located in a part of the garden that was directly over the hospital's operating rooms. Oasis informed the group that the rooftop garden would be technically sound and not present a risk to the hospital's operating rooms, or lead to any water damage. The green roof ballasted the two water features, and no penetrations of the waterproofing membrane were required.

Leading the discussions on the technical aspects of designing and constructing a rooftop garden, Oasis, along with green roof provider, Roofmeadow, coordinated with the architect on garden elements that impacted structural and roof integrity. Roof membrane interfacing, shade structures, water features and mechanical and electrical services all required close coordination among the design and installation teams. Oasis and Roofmeadow recommended modifications to the roof, specifically drain locations and structures, vent reconfigurations, and electrical and water source roof penetrations.

Surrounding the fountain are medicinal herbs that provide sensory benefits with their scents, colors, and textures, including mentha piperita (peppermint) and nepeta "Walker's Low' catmint. A dedication plaque sits in front of the fountain, and pavers surrounding the herb garden have donor names engraved into them. When additional donor names need to be added, they are etched into the existing blank pavers, which are easily removed and replaced.
Credit: Jane Luce

Creating a Sense of Place
Oasis' design includes a variety of accessible environments for socialization and privacy within the garden, and provides for easy access and circulation. People may sit near the two water features, within two different deck seating areas that are situated within planting beds, in a patio area under a wooden pergola that provides shade, or in a separate garden meditation area.

Two concentric circles within the garden represent the circle of life and include calming and restorative elements to encourage wellness and help reduce stress. The outer circle symbolizes life and the journeys that people take through life. The inner circle represents the circle of healing, and includes planting mounds with medicinal herbs that are fragrant and provide sensory benefits with their scents, colors, and textures.

A custom stainless steel fountain (above background) in the garden's inner circle serves as the garden's hub, a focal point from which four axes divide the garden into quadrants. Water rolls off the fountain's edges to create soothing, relaxing sounds amid plantings of "Hidcote' lavender, "Knockout' roses, purple coneflowers and Siskiyou evening primrose.
Photo: Oasis design group

Roof and Membrane Assembly
The roof assembly includes the roof deck, membranes, insulation and coverings. The garden is divided into 74 percent green space, and 26 percent hardscape, which provide a variety of landscape conditions, perform multiple functions and complement one another.

Two types of roof assemblies typically accommodate green roofs. Protected membrane roof assemblies, often referred to as Inverted Roof Membrane Assemblies (IRMA), place the insulation above the polystyrene-protected waterproofing membrane, whereas conventional roof assemblies place the insulation below the membrane. An IRMA assembly was put in place prior to the start of the garden installation. Placing rooftop garden assemblies above these systems required that the integrity of the existing systems be maintained and protected.

Oasis Design Group created the site plan and renderings for the Barbara Truland Butz Healing Garden that Shady Grove Adventist Hospital used to help solicit $1.4 million in donations, which funded 100 percent of the garden's construction.
Rendering: Oasis design group

Existing gravel ballast was removed in the garden to expose the existing insulation. An assembly of metal decking, a 6.25-inch concrete slab, root-repellant barrier layer, base drainage board, associated drainage system and separating filter fabric were applied along with the insulation layer. Once in place, the growing medium was placed at the specified depths and planted.

Drainage System
The varying media depths in the garden all have triangular conduits encased in granular drainage media for the drainage layer. The system provides a redundant system of drainage channels, which allows an evacuation route for excess water from the green roof. The drainage media is two inches deep in all zones, except within the stand-alone planters, where it is six inches deep. Drainage media depths vary slightly in the areas installed over the insulation layer. All subsurface drainage channels were routed to existing roof drains at the top of the slab.

Media Composition
The garden incorporates extensive and intensive roof garden plantings to accommodate various types of soils and depths.

The growing media is a specially blended mix of lightweight mineral aggregates and organic materials. Intensive profiles cover 73 percent of the garden's green space and were designed at varied planting depths; herbaceous planting areas have 18 inches of media depth; woody shrubs have 24 inches of media depth.

Meandering walking paths wind through a variety of garden areas planted with succulents and sustainable drought tolerant grasses, including feather reed grass, blue lyme grass and switchgrasses, arranged in a Zen garden meditation area. Various types of soils and depths accommodate a range of sustainable plant materials and extensive and intensive roof garden plantings, including caryopteris x clandonensis "Longwood Blue' bluebeard, "Husker Red' penstemon, and a variety of sages and sedums.
Photo: Oasis design group

The extensive profile (not more than five inches of growing media) covers the remaining 27 percent of the planting area, and was designed to allow a variety of sedums to thrive in unirrigated zones. Small trees were set in planters placed above the structural columns, which were the only positions where the intensive weight could be accommodated.

Irrigation
A variety of irrigation strategies were constructed within the garden and were designed to correspond with the requirements of the various planting zones. Drip irrigation is provided in the intensive planting zones. Extensive areas planted with sedums are unirrigated. The irrigation in the intensive areas was zoned according to the various plant requirements, i.e., shrubs versus perennials.

Workers put specially designed pergola footings in place to avoid roof penetrations. The footings were designed to sit on top of the roof's waterproofing membrane, in part to assuage staff concerns about rooftop landscape elements and water features that were installed directly above the hospital's operating rooms.
Photo: Oasis design group

Environmental Guidelines and Green Design Benefits
Considering the environmental implications of building new healthcare facilities has changed in recent years from an option to a requirement. Several green building industry rating systems, such as the Leadership in Energy and Environmental Design (LEED) from the U.S. Green Building Council and the Green Guide for Health Care, specify building performance standards that are environmentally friendly, and best practices to minimize impact on the environment.

These accepted industry standards have specific criteria, which can be applied to the development of rooftop gardens. The predominant benefit of green roofs to a site and the larger environment is the reduction of the urban heat island effect, through the replacement of what was an impervious surface with a membrane with vegetation. Green roofs also reduce the volume of stormwater runoff and delay the peak rate of runoff. Both are achieved by the absorptive capabilities of the soil medium and plants.

In addition to the aesthetic improvements, the green roof decreases urban heat island effect and stormwater runoff, improves water retention by 30 to 40 percent, and reduces ambient noise pollution by as much as 10 percent.
Photo: Oasis design group

Like most rooftop gardens and green roofs, the Barbara Truland Butz Healing Garden provides a wide array of environmental and building cost-saving benefits, especially in heating and cooling. In addition, the garden provides a much-needed respite for patients and staff members and contributes to the hospital's total healing and wellness experience.

The 20,250 square foot healing garden was completed June 1, 2010, after a seven-month construction period. The finished site is fully accessible and includes 1,330 square feet of shade for patients, visitors and staff. Recognition Since its completion, the Barbara Truland Butz Healing Garden has earned several awards, including the Merit Award from the Maryland and Potomac Chapters of the American Society of Landscape Architects in 2012; a 2012 Award of Excellence Eagle Award in the Sitework/Landscape category from Associated Builders and Contractors; a 2011 Grand Award from the Landscape Contractors Association; and a 2011 Grand Award from the Professional Landcare Network.

Project Team
Client
Shady Grove Adventist Hospital
Chief Development Officer, Shady Grove Adventist Hospital Foundation
William H. Smith
Architect
Wilmot Sanz
Project Architect/Manager
John Mattioli
Landscape Architect
Oasis Design Group
Principal-In-Charge
Scott C. Scarfone, ASLA

Design Team
Will Hart, ASLA; Josh Gulick, ASLA; and Kyle Mundy, ASLA
General Contractor
Whiting-Turner
Green Roof
Roofmeadow
Landscape Contractor
Ruppert Landscape
Structural Engineer
Cagley & Associates