Living Roof Helps Orcas Island Home Blend into the Landscape

This residence on Orcas Island is crowned with an extensive green roof from XeroFlor.
Photos: Terra Firma NW LLC

Orcas Island is a horseshoe-shaped island in the northwest corner of the state of Washington. With an area of 57 square miles, it’s the largest of the San Juan Islands, and accessible only by ferry. When a client approached him about building a custom home on the island, Justin Paulsen jumped at the chance. Paulsen is the owner of Terra Firma NW LLC, a general contractor located in nearby Eastsound, Washington. “We were hired directly by the owners to build the project from the ground up,” Paulsen notes.

The 3,400-square-foot home features 3,850 square feet of roof area, which is crowned with a living roof. The system specified for the project was a XeroFlor extensive green roof, which was installed on top of a PVC membrane roof manufactured by Versico.

The green roof system consists of a root barrier with a drainage composite, 1-1/4 inches of growing medium, and pre-vegetated sedum mats. The system was installed in the late fall in 2018, so many of the plants were dormant. Photos: Terra Firma NW LLC

“The roof system works well for the home, which is designed in the style of the Bauhaus school of design,” notes Paulsen. “The home features many linear design elements, and the green roof gives it a sense of blending in with the natural surroundings.”

It was only the second green roof Paulsen had been involved with, so he made sure to do his homework. He knew from experience that work on the island would pose logistical challenges, so he tapped a talented to team to help design and execute the project.

The Roofing Contractor

Paulsen wanted a skilled roofing contractor to install the waterproof layer beneath the green roof system. The Versico rep in the area, Ken Stillwell, recommended All Weather Rooftop Solutions, headquartered in Everett, Washington. The company, owned by partners Todd Severson and Greg O’Neill, typically focuses on commercial work, but this project was right in their wheelhouse. Severson knew the company had to plan ahead to ensure the everything went smoothly.

Crews from Terra Firma NW installed the green roof system. The sedum mats arrived on a pallet and were unrolled on top of the growing medium. Photos: Terra Firma NW LLC

“Working on the island was the biggest challenge of the whole project,” Severson notes. “We wanted to complete the project in one week, so we had to make sure we had everything ready to go. Everything had to be transported by ferry, so we had to schedule all of the trucks and make sure all of the material landed at one time. We just had to make sure we had all of the material and manpower on that ferry.”

The PVC roof system was installed over a plywood deck. Crews first installed two layers of 3.3-inch insulation to achieve an R-value of 38. Tapered insulation system was then added to ensure proper drainage. The insulation was topped with half-inch DensDeck Prime cover board, which was mechanically attached. A gray 60-mil PVC membrane from Versico was then fully adhered over the entire assembly.

All Weather crews also installed OMG SpeedTite roof drains with Vortex-breaker technology, as well as Solatube light tubes. The large skylight was installed by the manufacturer, CrystaLite.

All Weather Rooftop Solutions installed the PVC membrane to provide a waterproof barrier beneath the green roof. Photos: Terra Firma NW LLC

The sheet metal work was completed by All Weather on a second trip, with a smaller crew returning to complete the flashing and edge metal. The roofing portion of the project went smoothly. “Justin from Terra Firma was great work with, and our superintendent, Jeff Gale, did a great job quarterbacking it on our end,” Severson notes. “Everything went off without a hitch. It’s a pretty unique little structure.”

Paulsen agrees. “They did a great job installing the insulation and the membrane,” he notes. “The biggest thing we had to deal with after that was protecting the membrane from other trades. Our stonemason had to go back up on the roof and complete the chimneys.”

To preserve the integrity of the membrane after it was installed, Terra Firma crews cut a 20-mil pond liner pond liner into sections that were used to protect areas of the roof that had to be accessed by other trades.

Installing the Green Roof

After all the other work was completed on the rooftop, crews from Terra Firma installed the green roof system in the late fall of 2018. Paulsen had heard about XeroFlor from another contractor and did some research. He then contacted Clayton Rugh, director of XeroFlor America, to design and specify the system.

“I thought it was really top-notch system,” Paulsen notes. “I went to Clayton to document some other examples that had been installed in the area, and I pitched it to our client. Clayton did all of the functional engineering work on the green roof system and determined the soil requirements. The plantings by XeroFlor were sourced very close to the project site, which helps to ensure successful future growth.”

Photos: Terra Firma NW LLC

The extensive green roof system consists of a root barrier with a drainage composite, which is an open-flow zone of polymer coils with a bonded fleece fabric sheet. The drainage material was topped with 1-1/4 inches of growing medium, followed by 1-inch-thick pre-vegetated mats, which contained a mix of sedum succulents.

The pre-vegetated mats are installed just like sod. “They arrive rolled up on a pallet,” Rugh notes. “You just align the roll adjacent to the previously installed roll, abutting it tightly, and roll it into place.”

Terra Firma also installed the edge metal and rock ballast around the perimeter. “I was amazed at how simple it was to accommodate the green roof portion of the project,” Paulsen says. “Once the membrane was down, we knew we were rock solid and the house was well protected. The green roof portion was easy to install. I’d definitely do one again.”

Paulsen is proud to have this project under his belt. He can’t wait to see it in the spring, when the green roof is in its full glory.

“Terra Firma NW thrives on jobs that have complex and unusual requirements,” Paulsen says. “This job, from foundation all the way through the roof, presented numerous design challenges. We have a $2 million-dollar house under this roof. If I had to give advice to anyone doing a green roof, my advice would be: Don’t cut corners.”

TEAM

Architect:  Harlan Pedersen AIA, Orcas, Washington

General Contractor: Terra Firma NW LLC, Eastsound, Washington, www.tfnwllc.com

Roofing Contractor: All Weather Rooftop Solutions, Everett, Washington, www.allweatherroof.net

MATERIALS

Extensive Green Roof System: XeroFlor XF + GM Assembly, XeroFlor North America, www.xeroflornorthamerica.com

Roof Membrane: 60-mil PVC, Versico Roofing Systems, www.versico.com

Cover Board: DensDeck Prime, Georgia-Pacific, www.densdeck.com

Skylight: CrystaLite, www.crystaliteinc.com

Daylighting: Solatube, www.solatube.com

Roof Drains: SpeedTite roof drains, OMG Roofing Products, www.omgroofing.com

At The Wharf, Vegetative Roofs Play a Key Role in Storm Water Management

The Wharf is a riverfront community spanning nearly a mile of the Potomac River. The neighborhood features high-end hotels, luxury condominiums, retail shops, commercial offices and a music hall. Photos: The District Wharf

According to the Washington D.C. Department of Energy and the Environment, the District is home to more than 3 million square feet of vegetative roof assemblies (VRAs). A commitment to responsible storm water management has helped the nation’s capital rank first among U.S. cities when it comes to green roofs installed. From the massive 500,000-square-foot VRA atop the Douglas Munro U.S. Coast Guard headquarters (featured in the September/October 2018 issue of Roofing) to elegant boutique cocktail bars, VRAs are helping Washington, D.C., manage storm water runoff and providing unique vantage points for taking in national landmarks. The Wharf, in the District’s Southwest quadrant, represents a “neighborhood” approach to green roofs.

A riverfront community spanning nearly a mile of the Potomac River, The Wharf is a mixed use, public-private development, including high-end hotels, luxury condominiums, retail shops, commercial offices and even a 6,000-seat music hall. While the design and aesthetics of different buildings at The Wharf project a sense of diversity, VRAs are a unifying element. In addition to providing visual interest and elevated spaces for public gatherings, VRAs help The Wharf achieve its sustainability and water management goals.

Managing Storm Water, Supporting Sustainability

Water has long been a defining element of life in the District, whose neighboring waterways include not only the Potomac, but also the Anacostia River, Rock Creek and Chesapeake Bay. To help manage storm water runoff, the District makes use of a massive cistern system, permeable pavements, and extensive use of vegetative bio-retention supported by VRAs. The District of Columbia’s Department of Energy & Environment mandates measures that retain runoff from a 1.2-inch storm event through green infrastructure and capture reuse systems. Specific storm water retention rates are specified relative to a building’s footprint.

The vegetative roofs help tie together the diverse types of buildings in the area. Photos: The District Wharf

In addition to helping manage storm water runoff, protected roof membrane assembly (PRMA) systems at The Wharf also help to support the development’s sustainability performance goals, which started at the master planning stage. Sustainability objectives supported by The Wharf’s VRAs include reducing storm water discharge and improving thermal performance through the cooling and shading properties of soils and plantings — an important consideration in a region renowned for its humid summers. VRAs are also desirable in urban areas for the role vegetation can play in helping filter pollution and providing habitats for birds and other wildlife. Finally, VRAs offer an aesthetically pleasing environment for employees, occupants and visitors.

The Wharf development was designed to achieve LEED Gold, while individual buildings targeted LEED Gold or Silver. Constructed in phases, Phase One opened in 2017 and took nearly 15 years to complete. While the Great Recession slowed construction, an “upside” of the delay was that a proliferation of PRMA assemblies across the District helped inform the assembly of green roofs at The Wharf. Several high-profile buildings that employ similar roofing systems include the MGM Casino, the National Museum of African American History and the National Archives.

A PRMA Approach to Support Performance

More than half of the roofs in The Wharf make use of an Owens Corning PRMA that includes Owens Corning FOAMULAR 404 and 604 extruded polystyrene insulation (XPS) supplied by PPSI Maryland. XPS delivers unique water resistance and strength properties that differentiate it from other insulation products and make it ideal for VRA applications. In fact, the demanding conditions on rooftops helped prompt the National Roofing Contractors Association (NRCA) recommendation to use only XPS insulation for VRA applications. The innate water resistance of XPS helps a roofing system retain its R-value and energy-saving power while retaining its compressive strength to bear a significant amount of overburden. Strength is critical in a PRMA application, as the insulation must be able to withstand the weight of vegetation, rainfall, growing media, pavers and surrounding surface materials.

Sustainability objectives supported by The Wharf’s VRAs include reducing storm water runoff, improving thermal performance, and providing habitats for wildlife. Photos: The District Wharf

At the highest levels, the rooftop plants and vegetation help serve as a giant sponge to absorb the rainwater. In a PRMA roof, insulation under the plant layer, growing media and filter/drainage layer is placed above a waterproofing layer which directs water horizontally to a series of overflow vaults. A network of massive 700,000-gallon cisterns throughout the District collect and control the release of water.

In addition to water, wind was another consideration when planning VRAs at The Wharf. Rock curbs from Hanover Architectural Products help mitigate against winds coming in off the riverfront. Other roofing materials that help The Wharf PRMAs achieve performance include waterproofing membrane 790-11 Hot Rubberized Asphalt by the Henry Company, EMSEAL expansion joints to tie together air barriers, and Hanover Architectural Products pavers and sedum mats supplied by Sempergreen.

Contractor Coordination and Communications Are Key

As a community-focused development, The Wharf celebrated its grand opening with several public events. Hometown rock band the Foo Fighters performed for a sellout crowd at the Anthem music center on October 12, 2017. The enormous task of completing multiple buildings against a very tight timeline was a challenge felt by all of the contractor trades on site, according to Brian Davis, general superintendent at James Myers, the roofing contractor charged with installing green roofs at The Wharf. The immensity of the project required careful scheduling and logistics among roofers and other trades. Teams worked throughout the night and seven days a week as Phase One approached completion.

Photos: The District Wharf

As the countdown to the October 12 grand opening approached, construction teams followed tight schedules outlining exactly what team members would be working in what area at a particular time. The logistical demands of building nine buildings over six blocks made traffic bottlenecks an ongoing challenge throughout the project. Scheduling details had to consider not only the District’s notorious rush hour traffic but also events and attractions in the area. For example, the Washington Nationals baseball team played a number of weeknight baseball games at home. Trades working on The Wharf were required to clear the streets three hours before the first pitch of each Nationals home game. While navigating event schedules and a tight construction schedule, contractors also had to maintain high levels of safety and quality.

The public event commemorating the completion of Phase One celebrated a one-of-a-kind public space winding along one of the nation’s most historic riverfronts with an epic rock concert. More quietly, the completion of Phase One celebrated Washington’s role as a leader in the installation of VRAs while helping the District achieve sustainability goals and comply with storm water management mandates.

MATERIALS

Insulation: FOAMULAR 404 and 604 extruded polystyrene, Owens Corning, www.owenscorning.com

Waterproofing Membrane: 790-11 Hot Rubberized Asphalt, Henry Company, www.henry.com

Expansion Joints: EMSEAL, www.emseal.com

Sedum Mats: Sempergreen, www.sempergreen.com

Pavers: Hanover Architectural Products, www.hanoverpavers.com

Contractor Overcomes Challenging Logistics to Re-Roof 16-Story Westin Savannah

The Westin Savannah site posed logistical challenges, as it is bordered by the Savannah River, a canal and the Savannah Convention Center. Photo: SOPREMA

Were you to visit Savannah, Georgia, the Westin Savannah Harbor Golf Resort and Spa would be tough to miss. This landmark property, known for its 18-hole PGA golf course, secluded beach access and on-site spa, is the tallest building in the city at 16 stories. The aura of luxury surrounding the building was threatened, however, when Hurricane Matthew moved through the region, inundating the city with rainwater and causing the aging Westin Savannah roof to fail. With leaks resulting in the closure of a major portion of the hotel’s upper floor, it was clear the building owners would need to move quickly to restore a waterproof seal atop their building.

The job would not be easy. The Westin Savannah is surrounded by the Savannah River on one side, a canal on another and the Savannah Convention Center on a third. The only feasible area left to stage and load the roofing material onto a crane was the front parking loop and valet area — an area that would typically be avoided with any other roofing project. “We only had one spot where we could set up, and that was the biggest challenge,” says Larry Hoffman, the superintendent who oversaw the installation of the roof at the Westin Savannah on behalf of Whitco Roofing, the Westin’s chosen contractor. “We were very limited with regard to any mobility around that hotel, not to mention the fact that we had to get materials onto a roof that was 270 feet from the ground.” 

Envisioning an Approach

The Whitco Roofing team also had to deal with challenging application conditions, given that the roof had many penetrations due to the presence of air conditioning units, towers, exhaust vents, lighting, walkways, ladders, staircases and other equipment. Special care would have to be given to the installation of the flashing to ensure no opportunities for leak formation remained after the roofing job was done. Recognizing that the use of a liquid flashing material was the best bet to keep the roofing layer monolithic despite all the penetrations, the Whitco Roofing team set about selecting the right compatible materials for the job.

SOPREMA’s SENTINEL P150 60-mil PVC-based roofing membrane was selected for the projectbecause we wanted a durable roofing product that was compatible with a liquid flashing material for difficult base flashings encountered during this project,” explains Henri Brickey, director of business development for Whitco Roofing. “We recommended the SOPREMA PVC membrane for several reasons, the first of which is the superior chemical and UV resistance PVC offers over TPO. Since we also intended to wrap the large quantity of concrete and metal support column bases with SOPREMA’s ALSAN RS 230 Flash polymethyl methacrylate (PMMA) liquid resin, we made sure the PVC membrane was compatible and that we could include those areas under the roof’s warranty.” 

The Installation Commences

The complex coordination required for a successful roofing installation began on the ground. One week’s worth of material was staged at a time, then a crane was brought in to upload materials to the roof on the same day trash was being downloaded from the old roof tear-off process. All debris had to be carefully bagged and secured with tarps to avoid pollution in the nearby Savannah River, and the delivery and removal of four dumpsters at a time had to be carefully coordinated so that no dumpster was left on the premises overnight, blocking entry to the building. “You had to be out of there by five o’clock with everything, and it had to be done in a particular sequence, further complicating matters,” explains Hoffman.

On the rooftop, existing asphalt-based roofing materials were stripped down to the concrete deck. SOPREMA SOPRA-ISO3.5-inch polyisocyanurate insulation was adhered using SOPREMA DUOTACK 365 foam adhesive to provide improved R-value to the building. Next, the PVC membrane was bonded onto the insulation, providing both a reliable waterproofing layer and a reflective white finish that would help diminish heat absorption compared to the older materials. The liquid resin coating was then applied to prevent water intrusion at all exposed concrete column bases — extending up and coating metal base plates — and at vertical flashing points where air handling units tied into the building’s walls. New tapered crickets were also installed between drains, improving the overall flow of water on the roof and reducing the opportunity for ponding water.

Safety and Communications Prioritized

Throughout the project, OSHA guidelines had to be followed carefully on the rooftop and on the ground to ensure both workers and bystanders entering and exiting the hotel were safe. Flagging and ground guides were used around the staging area, and strict adherence to timelines for deliveries and mobilizations were also critical to the safe execution of the project. The Whitco Roofing team worked closely with the hotel management throughout the process to prevent interference with hotel operations and to minimize risks to guests. 

The building now benefits from a superior roofing membrane that is Energy Star-compliant, upgraded insulation, a strong foam adhesive that helps resist uplift pressure during storms and a monolithic waterproofing layer thanks to the liquid flashing installed around all penetrations. “SOPREMA’s single-ply membranes have a reputation for strength and durability,” notes Brickey, “and especially with the inclusion of the liquid flashing system to deal with difficult flashing details, we were able to provide a long-lasting, warranted waterproofing solution for the Westin.”

In all, more than 14,000 square feet of roofing material was replaced over the course of roughly a month by a large team of installers. In part because the hotel staff was so pleased with the way the job was planned, managed and executed, Whitco Roofing was brought back to install a new roof on a lower section of the building as well. That project was recently completed, positioning the Westin Savannah to resist the elements while serving as a relaxing getaway for the foreseeable future.

TEAM

Roofing Contractor: Whitco Roofing, Atlanta, Georgia, www.whitcoroofing.com

MATERIALS

Roof Membrane: SENTINEL P150 PVC, SOPREMA, www.soprema.us

Insulation: SOPRA-ISO, SOPREMA

Adhesive: DUOTACK 365, SOPREMA

Liquid Flashing: ALSAN RS 230 Flash, SOPREMA

Contractor Shows Versatility During Spectrum Field Restoration

Spectrum Field in Clearwater, Florida, is home to the Philadelphia Phillies in spring training and its minor league affiliate, the Clearwater Threshers. TarHeel Roofing replaced the main roof and restored and waterproofed the walls. Photo: TarHeel Corporation

TarHeel Corporation was founded as TarHeel Roofing in 1981. Headquartered in St. Petersburg, Florida, the company specializes in commercial work including roofing, waterproofing, cladding, damp proofing, exterior renovations, lightning protection and sheet metal. According to John Looney, president and owner of TarHeel Corporation, the company’s name was changed to better reflect its ability to work on the entire building envelope, including above- and below-grade waterproofing. 

When nearby Spectrum Field needed roofing and waterproofing work, Looney saw the project as a perfect opportunity to show off the company’s versatility. The stadium is home to the Philadelphia Phillies during spring training, and it also serves as the home field for the team’s minor league affiliate, the Clearwater Threshers. “We’ve done a lot of sports complexes in the past,” notes Looney. 

TarHeel Roofing restored the roof two years ago, and this year the company waterproofed the walls. The scopes of work included cold-applied roofing, waterproofing, caulking, and glazing, as well as repairing the tie-ins to pedestrian deck areas. “There were a lot of little pieces here that were right in our wheelhouse,” Looney says. 

Roofs and Walls

When the stadium’s existing modified bitumen roof reached the end of its service life, the decision was made to restore it with Garland’s Energizer K Plus FR. “We used Garland’s Energizer system, a cold-applied system with polyester mesh and granule surfacing on it,” Looney notes. 

The roof was restored with Garland’s Energizer K Plus FR system, a cold-applied roofing restoration system with granular surfacing. Photo: The Garland Company Inc.

Some perimeter areas of the roof were removed and repaired after an infrared scan was used to detect any moisture, and then the entire roof surface was cleaned and primed. The fluid-applied system is installed in two coats with a polyester or fiberglass scrim sheet fully adhered into it. Immediately after the second coat, granules are broadcast over the entire surface. “The finished product is very good-looking,” says Looney. 

Work on the vertical surfaces began in September 2018. The complex features walls clad in an exterior insulation and finish system (EIFS), as well as concrete and concrete masonry unit (CMU) walls. “The EIFS, concrete, and CMU walls each required a different application, but the basic scope of work is the same for each, with some variations,” Looney says. 

The walls were first cleaned and repaired. After the walls were pressure washed, crews repaired and replaced caulking at windows, doors and other penetrations. Cracks were filled using Garland’s Green-Lock Sealant XL, a polyether joint sealant with no VOCs. “We took care of cracks in the concrete and any breaks, including damage from baseballs hitting it,” Looney says. “Once the surface was repaired, we moved on the coating application.”

Crews applied Garland’s Tuff-Coat acrylic architectural wall coating. The coating can be applied with either a sprayer or rollers. Both methods were used on the project, but the majority of the work was done with rollers. The tan color was a crucial concern for the owners, and up-front testing ensured the tint would match up perfectly on the various substrates. “There was also some striping involved for aesthetics,” notes Looney. “We put on a band of a darker accent color.”

Crews from TarHeel Roofing cleaned and repaired the walls and waterproofed them with Garland’s Tuff-Coat acrylic architectural wall coating. Photo: TarHeel Corporation

The schedule was sometimes adjusted to accommodate concerts and other events. “The most unusual thing is the actual use of the building, obviously, being a baseball park with a lot of public access,” he says. “It takes a beating from all of the use and people there.”

Accessing some of the wall areas on the site was the biggest challenge on the project, according to Looney. “If you can picture the typical ballfield, you’ve got anything from ground-level vertical walls up to walls tucked behind seating up in the grandstand,” he explains. “Logistically, the challenge was getting access to all of the areas, extending from public concourses all the way up to the owner’s boxes and suites. A lot of that work was done from ground level, actually out on the field, reaching up with big Hi-Los that extended over two or three sections of seating.”

When figuring out the best approach, safety is always the primary concern. “Safety is a big part of any project, beginning with preparation and layout,” Looney says. “Once we were awarded the job, we weighed working from ladders, swing stages, and man lifts. In this project, we opted to do most of it from man lifts because of the safety concerns inherent in working from ladders, swing stages, or even scaffolding in some of these areas.” 

Major-league workmanship is the key to earning repeat business, says Looney. “We don’t do much advertising,” he says. “To us, that means every job has to be done well enough to be asked back. We pay a lot of attention to the details, including safety and the setup. To us, the finished product has to be great — that’s a given — but also the journey, from the start to the completion, is important as well. We do a lot of work on hospitals, health care areas, and industrial sites where us being in the way really isn’t an option. We are very familiar with working around the needs of businesses. So from a logistics and detail point of view, we are very sensitive to making sure the ride is as good as it can be.”

TEAM

Roofing and Waterproofing Contractor: TarHeel Corporation, St. Petersburg, Florida, www.tarheelcorp.com

MATERIALS 

Roof Restoration System: Energizer K Plus FR, The Garland Company Inc., www.garlandco.com

Wall Coating: Tuff-Coat, The Garland Company Inc.

Joint Sealant: Green-Lock Sealant XL, The Garland Company Inc.

At the Ace Hotel, Versatile Rooftop Terraces Capture the Imagination

Located in Chicago’s Fulton Market Historic District, the Ace Hotel features several vegetative roofs and a rooftop bar. Photos: Scott Shigley for site design group ltd.

The Ace Hotel is located in Chicago’s Fulton Market Historic District. It features 159 guestrooms and amenities including rooftop event spaces with stunning views of the city. The complex features several vegetative roofs, including a large fifth-floor terrace and a seventh-floor rooftop bar. The fifth-floor terrace incorporates a sculpture that visitors can climb on and areas that can easily adapt to host a variety of events, from corporate meetings to yoga classes.

The team at site design group ltd., the Chicago landscape architect on the project, worked closely with the lead architect, GREC Architects, and the Ace Hotel team to determine the key design goals for the rooftop spaces. Hana Ishikawa, design principal at site design group, notes the client was looking for an understated design. “In this project, what they really wanted was a prairie that kind of got left on the roof,” she says “So, that’s where the project got started.”

The fifth-floor terrace incorporates a sculpture created by artist Jonathan Nesci that visitors can climb on. An area topped with pavers is used to host a variety of events. Photos: Scott Shigley for site design group ltd.

On the fifth-floor terrace, the materials and plants chosen are meant to evoke a natural prairie landscape, while a section topped with pavers serves as a versatile event space. “We were really focused on creating a space that was super flexible,” Ishikawa says. “You’ll notice there’s a really large pavement area in the front, and they hold all kinds of interesting events there. That’s used pretty frequently, whether it be yoga or the little markets they hold up there. One of the primary functions we needed was a lot of flexibility, and that area works well for that.”

Other roof sections that were not open to the public had different needs. It took a talented team of design, manufacturing and construction professionals to turn the vision for the hotel’s rooftop spaces into reality — and provide the single-source warranty the architect and owner desired. 

A Versatile Roof System

The roof system specified for every roof level was a variation of Hydrotech’s protected membrane roof (PMR) assembly. According to Dennis Yanez, American Hydrotech’s national marketing manager, the foundation of the PMR assembly consists of Hydrotech’s Monolithic Membrane 6125, a hot fluid-applied rubberized asphalt membrane, which is applied directly to the deck and topped with Dow Styrofoam insulation. The system can then incorporate a variety of options including pavers, ballast, and extensive and intensive roof gardens. “The basics — the roofing/waterproofing membrane and the Dow Styrofoam — don’t change,” Yanez says. “One of the advantages of this system is once you apply the membrane and insulation in the field, you can mix and match all of these options and you aren’t changing the integrity of keeping that structure watertight.” 

Kevin Serena, Hydrotech’s garden roofing technical sales coordinator for the central region, worked with the building owner and design team to select the products and systems for each rooftop section. 

The materials and plants chosen for the roof terrace are meant to evoke a prairie landscape, with a trail leading to seating areas. Photos: Scott Shigley for site design group ltd.

“They have a few different roof levels, and there was a different design intent for each area,” Serena says. “There are a few upper roofs that only the occupants of adjacent buildings will see, so what they wanted there was low-maintenance vegetation with good coverage. They went with a sedum mat material. It’s pre-grown outside for over a year, so it’s a very hardy material, and once it becomes established it needs little to no maintenance. That was a goal of theirs for those upper roofs since not a lot of people would be accessing those areas.”

For the large podium deck that was open to the public, the owners wanted to add more interesting vegetation along with other features. “They integrated stone walkways, and they used a more expansive plant palette,” Serena notes. “They used the same sedum carpet as a base planting, and then added some different perennials and grasses throughout the mat to give it some vertical interest and add some biodiversity to the roof.”

Serena also worked closely with the roof system installer, Bennett & Brosseau Roofing Inc., of Romeoville, Illinois, an authorized Hydrotech applicator. “Bennett and Brosseau is one of the best contractors in the area,” Serena says. “They have taken a real interest in doing not only the membrane but all the way up through the growing media and vegetation. They are really into doing the green roof, so they are exciting to work with. They really like doing this type of work, and they do a great job.”

The Installation

Bennett & Brosseau Roofing installed all of the roof systems on the project, as well as the material for the garden roofs. The company also fabricated and installed four custom colors of sheet metal on the project. 

“We had grade-level to roof-level waterproofing on this project,” notes Jim Brosseau, CEO and owner of Bennett & Brosseau Roofing. “On the grade level, we installed pavers and drainage components. We also planted plants and trees in the planters on the plaza and at the grade level as well.”

Photos: Scott Shigley for site design group ltd.

The hotel was constructed at the site of a former cheese-making factory in the Fulton Market District. A part of the existing building was retained, including a wall with a historic mural, but the majority of the project was new construction with a concrete roof deck. “It was in a tight area where access was very limited at the jobsite,” Brosseau notes. “All of the roofs were new, but the owner wanted to tie into an existing wall for historical value.”

Bennett & Brosseau Roofing worked closely with Hydrotech to coordinate material deliveries, and access to the jobsite was eased by a couple of fortuitous events. “One of our vendors actually had some property behind the jobsite, so we were able to stage some material there,” Brosseau recalls. “They also closed the street for some work at a building across the street, so we took advantage of that and were able to stage some material on the street and lift it up with our hoists.” 

Elevators did not reach every level, complicating the logistics. “Safety was a challenge,” Brosseau says. “They had elevators at certain levels, but the rest we had to stage a second time for a double hoist. We had to have certified riggers and an approved lift plan. Every pallet is marked, and Hydrotech does an excellent job packaging material, so that helps the process.” 

Crews installed fall-protection barriers, which included the company’s own engineered bracket system with two-by-fours, as well as a Garlock safety rail system. Roofing work began on the penthouse roofs and the tops of the elevator shafts. “All of the roofs received Hydrotech’s hot fluid-applied rubber,” says Brosseau. 

Photos: Scott Shigley for site design group ltd.

The membrane is installed in two coats. The first coat is 90 mils with fabric reinforcement on top. The second coat is 125 mils, for a total of 215 mils. The hot rubberized asphalt, which is heated to 350-375 degrees, and cools as a solid, forming a monolithic membrane. “The membrane is adhered directly to the deck, and it forms one contiguous layer from parapet to parapet,” Yanez says. “They basically make a bathtub up on top of that roof, and then with all of the other design elements, you can do structural construction on top of the Styrofoam. It’s a much simpler, easier system, and the reality is there are fewer opportunities for it to fail because it’s a very simplistic approach.”

“Hydrotech’s system is easy to work with,” Brosseau notes. “The liquid is a very good product to work with on tough details. Another big advantage of the Hydrotech system, especially in this case, is that it isn’t temperature sensitive.”

Living Roofs

Sections of the roof with limited access were topped with an extensive vegetative system featuring Hydrotech’s InstaGreen sedum mat. River rock was applied as a perimeter border. “We’d get them watertight, and then we’d come back and install the garden systems after the other trades were done on the roof,” Brosseau explains. 

On the fifth-floor terrace, Bennett & Brosseauinstalled pavers, wood steppers and wood benches made from reclaimed Robinia. “We put down granite for pathways,” Brosseaunotes. “We had ballast, intensive garden, extensive garden, pavers, logs and the granite walkway. On Level 5, we had a lot going on.”

The material changes and the ground changes were designed to represent an actual prairie, according to Ishikawa. “There is a little trail that goes off and creates a little circle of seating,” she notes. 

Native grasses were chosen to provide visual interest and survive Chicago’s tough winters. These plants were plugged into the sedum mat to ensure the living roof would have complete coverage at the outset. “That was important to us so that the area wouldn’t be trampled while the native grasses and flora were emerging,” says Ishikawa.

Brosseau credits the support of the manufacturer before and during the project as the key to navigating all of the many details. “We regularly consult with Hydrotech’s technical department on non-standard details,” he says. “We’ll brainstorm to determine what the best solution is. There is also a value beyond that, and that is it helps the owner and the general contractor to see Hydrotech come out and recommend different ways to attack a problem.”

Bennett & Brosseau also installed edge metal, beam wraps, expansion joints, scuppers and downspouts. “The sheet metal was probably the most difficult part of it,” Brosseau says, “We custom fabricated everything in our shop. No two details were the same. For the bar area on Level 7, we fabricated a stainless-steel bar top for them as well.” 

It’s a Jungle Gym Out There

Crowning the fifth-floor roof area is a Nesci dome, a climbable sculpture created by artist Jonathan Nesci that has been likened to an “adult jungle gym.” According to Ishikawa, the blue metal design was inspired in part by the Louis Comfort Tiffany Dome in Chicago’s Cultural Center. “That one is an absolutely gorgeous Tiffany Dome with mosaic tile and glass,” Ishikawa notes. “This one is about the exact size and shape, so it’s kind of a reference of that cultural institution on top of the Ace Hotel. It’s meant to be a climbable, playful structure.”

“This roof is really exciting to us because it’s a very playful design,” Ishikawa continues. “Our firm in general believes that playful design also makes really loved landscapes. We were very excited to work on that part of it.”

Yanez points to the versatility and durability of the roof system as the key to a successful project that provides a long service life and the peace of mind of a single-source warranty. “We are happy to be able to give the market what it wants, and a lot of that hinges on the design creativity and pushing the envelope that the architects do,” he says, “We are very good at adapting to that and offering them a rock-solid assembly that, if applied correctly, should last the lifetime of that structure.”

TEAM

Lead Architect: GREC Architects, Chicago, Illinois, http://grecstudio.com

Landscape Architect: site design group ltd., Chicago, Illinois, www.site-design.com

General Contractor: Power Construction Company, Chicago, Illinois, www.powerconstruction.net

Roofing and Waterproofing Contractor: Bennett & Brosseau Roofing Inc., Romeoville, Illinois, www.bennettandbrosseau.com

MATERIALS

Roof Membrane: Monolithic Membrane 6125-EV, Hydrotech, www.hydrotechusa.com

Membrane Reinforcement: Hydroflex RB II-Hydrotech

Insulation: 60 PSI Extruded Polystyrene Insulation, Hydrotech/Dow, www.dow.com

Drainage Material: GR30 Water Retention and System Filter, Hydrotech

Flashing: Flex-Flash MB Granulated Flashing, Hydrotech

Growth Media: Litetop Intensive Media, Hydrotech

Vegetation: InstaGreen Sedum Carpet, Hydrotech