New NHL Practice Facility and Community Center Sports Vegetative Roof

The American Hydrotech Extensive Garden Roof Assembly was installed on two sections of the roof. The system was topped with pre-grown mats featuring mature sedum plants. Photo: American Hydrotech Inc.

The Chicago Blackhawks have captured the hearts of the city of Chicago along with three Stanley Cups in the last decade. The Blackhawks routinely lead the league in attendance at the United Center, and fans were excited when the team announced it would build a new 125,000-square-foot training facility and community center in downtown Chicago.

Completed earlier this year, the MB Arena features two NHL-sized ice rinks and other amenities including a fitness center, dining options, and spaces that can be rented for outings and events. The facility is the practice site for the Blackhawks and also hosts youth hockey, adult hockey leagues and public skating.

When plans for the project were unveiled, architects and planners mandated the facility meet or exceed all green and sustainable standards for the city. Chicago has been a leader in promoting vegetative roofs to help control storm water runoff, and this new construction project was no exception. The arena includes the construction of 24,000 square feet of green roof systems to complement the structure’s 68,000-square-foot main roof. A 60-mil TPO system manufactured by Carlilse SynTec was specified for the upper roof assembly, and plans called for an American Hydrotech Extensive Garden Roof Assembly to be placed on two lower sections of the roof.

The Garden Roof Assembly

Architect HOK worked with American Hydrotech during the design stage to select roofing components and plants that were optimized for the climate conditions and the building’s structural limitations.

According to Dennis Yanez, national marketing manager, American Hydrotech, and Kevin Serena, garden roofing technical sales coordinator for the central region, the structure’s metal deck necessitated a lightweight system.

The 125,000-square-foot facility 24,000 square feet of green roof systems that complement the structure’s 68,000-square-foot main roof. Photo: Chicago Blackhawks.

“Our 4-inch extensive garden roof system was ideal for this project,” says Yanez. “Since part of this project had a metal deck, there are more structural capacity concerns than with a concrete deck, so we were able to put together a lightweight, built-in-place system.”

The assembly consists of a hot-applied rubberized asphalt membrane, MM6125, which is applied to the roofing substrate to form a monolithic coating. It is topped with a root barrier and Dow Styrofoam insulation. The system also incorporates Hydrotech’s Gardendrain GR15, a molded polyethylene panel designed to retain water, filter fabric, lightweight growing media, and mature plants.

The plants are installed in the form of the InstaGreen Sedum Carpet, a pre-grown mat that comes in 25-square-foot rolls. It contains between nine and 15 different types of sedum and provides instant coverage when it is installed.

Key benefits of the system include reducing the urban heat island effect, purifying the air, and limiting storm water runoff, notes Yanez. “The Extensive Garden Roof Assembly is able to capture more than 1.5 inches of water on the roof, which plays a major role in storm water management,” he says.

The system also protects the membrane from ultraviolet (UV) degradation and damage from wind-blown debris. “Most importantly, for us, a garden roof is just another version of a PMR, or protected membrane roofing,” says Yanez. “Because the membrane is always in a PMR application, with Dow insulation over it, whatever ballast — whether it’s gravel ballast, or architectural pavers, or the garden roof assembly — is in place makes it literally impossible for the membrane to get damaged. It also mitigates the climate swings, keeping the membrane at a more constant temperature year-round.”

This system has a proven track record, according to Yanez. “We’ve been doing this going back 50 years on parking decks under regular topsoil, where weight wasn’t a concern,” he points out. “This is just a more modern version of that, but we’re putting it on the 4th, or the 14th, or the 99th floor.”

The Roofing Installation

All American Exterior Solutions, Lake Zurich, Illinois, is an approved applicator for both key manufacturers. The union contractor installed the Carlisle TPO system on the building’s main roof and the Hydrotech green roofs on the two lower roof levels.

Willie Hedrick, division manager at All American Exterior Solutions, notes that the TPO roof was installed first. “The deck was acoustic, so first we had to lay strips insulation in the flutes over the entire main roof,” he says.

The lightweight growth media was lifted to the roof in 2-yard totes. Photo: Christy Webber Landscapes.

Areas that housed mechanical equipment were reinforced with two layers of 5/8-inch DensDeck from Georgia-Pacific. Two layers of 2.6-inch insulation were then installed, followed by the 60-mil TPO, which was mechanically attached using the RhinoBond system from OMG Roofing Products. The attachment system uses induction welding technology to attach the membrane to the fasteners and plates that secure the insulation — without penetrating the membrane.

The main roof was originally designed as fully adhered system, but work began in January, and the temperature constraints ruled out some adhesives. “Once we made the switch to RhinoBond, we were able to install the membrane even though we did it during the winter,” Hedrick says.

Most of the TPO roof was surrounded by high parapet walls, and in other areas the safety perimeters were marked with flags. “At a few points at the highest points of the main roof we had to put up some the flags, and if you were outside of the flags you had to be tied off,” notes Hedrick. “The mid-roofs had short parapet walls, and on those roofs, we set up flags and had 100 percent fall protection outside the safety perimeter. For the lower green roof, we put guardrails up on the parapet to eliminate the fall hazard.”

The Garden Roofs

After the TPO sections were installed, work began on the extensive garden roof assemblies. The mid-roof had a metal deck, so the first step was to screw down 5/8-inch USG Securock cover board and strip in the seams. “At that point, we installed the liquid-applied membrane and the protection board,” Hedrick says.

The second green roof was installed over a concrete deck, so the application was a bit different. The membrane was applied directly to the concrete. A late change was made in the configuration of the lower green roof to take advantage of the space. “The owner decided to add a terrace to the lower green roof so people could walk out and see the roof and views of the city,” Hedrick recalls.

Before the growing media and plants were added, electronic field vector mapping (EFVM) was conducted by International Leak Detection to determine if there were any voids in the membrane. “You’ve got to confirm everything is 100 percent watertight before we start setting the components down,” Hedrick says. “We usually do the test and start putting the components down the next day to minimize exposure. The subcontractor we worked with to do the landscaping, Christy Webber, performed well. Since some of the components are loose laid, we worked with them to put down enough soil to hold everything in place. We worked hand-in-hand getting the all of the components and soil in.”

The Landscape Work

Jim Waldschmidt, project manager for Christy Webber Landscapes, Chicago, oversaw the installation of the lightweight growing media and sedum mats on the roof. Christy Webber is a full-service union landscaping company, and Waldschmidt notes that roofing work is a small but growing share of the company’s business. “We work with a few different commercial roofers,” he says. “This year we’ve done maybe 10 commercial projects.”

After the growing media was evenly spread out, the sedum mats were laid into place by crews from Christy Webber Landscapes. Photo: Christy Webber Landscapes.

Logistics at the site made for an easy delivery and setup — an unusual situation in downtown Chicago. “We were able to deliver the soil almost a week before we were scheduled to go out there, so we had everything on site and knew we wouldn’t have to worry about waiting,” Waldschmidt notes. “We just had to bring in a crane and lift up the soil bags. We had a pretty easy installation compared to other green roofs we’ve done.”

Growing media was lifted to the roof in 2-yard tote bags, which were cut open to disperse the contents. Three days after the growing media was in place, Christy Webber crews returned to install the sedum mats. “The sedum mats are delivered on pallets almost like the way a roll of sod would be delivered,” says Waldschmidt. “We just had to set the pallets on the roof, pull off the sedum mats and unroll them.”

A temporary irrigation system was set up to help the plants get established in the hot July temperatures. “Everything looks great now,” Waldschmidt says. “All of the sedum up there is thriving.”

Growth Sector

In this high-profile project, with a high-profile owner, making sure the system was error-free was critical, notes Serena. “Chicago is definitely the leader in vegetative roofs, and has been for more than 10 years,” he says. “This is another prime example. There was never a question whether this building would have a green roof on it. It’s a credit to Chicago, and it is a credit to the Chicago Blackhawks.”

Hedrick is proud to be part of the green roof movement. “I like the challenge, and I like the diversity,” he says. “When the Blackhawks went to the Stanley Cup championship and the blimp was hovering over the arena, I could see a couple of my projects on TV. It reminded me of all the time, effort, attention to detail, and collaborative hard work that it took to produce the final product. We’re turning typically unusable roof areas into useful space for amenities.”

The key driver of green roofs is storm water management, notes Yanez, but turning rooftops into useful space is another key benefit. “We’re seeing more and more city incentives for storm water management,” he says. “In urban areas, people are also taking advantage of existing space with green roofs. It’s a growing industry — pun intended.”


Architect: HOK, Chicago,
General Contractor: James McHugh Construction, Chicago,
Roofing Contractor: All American Exterior Solutions, Lake Zurich, Illinois,
Landscape Contractor: Christy Webber Landscapes, Chicago,


Garden Roof System:
Cover Board: Securock Gypsum-Fiber Roof Board, USG,
Membrane: MM6125 hot rubberized asphalt membrane, American Hydrotech Inc.,
Protection Sheet: Hydroflex 30, American Hydrotech Inc.
Root Barrier: Root Stop, American Hydrotech Inc.
Insulation: DOW Styrofoam, DOW Chemical,
Drain Board: Gardendrain GR15, American Hydrotech Inc.
Filter Fabric: System Filter fabric, American Hydrotech Inc.
Growing Media: LiteTop Engineered Growing Media, American Hydrotech Inc.
Plants: InstaGreen Sedum Carpet, American Hydrotech Inc.

TPO Roof System:
Membrane: 60-mil TPO, Carlisle SynTec,
Cover Board: DenDeck, Georgia-Pacific,
Attachment System: RhinoBond, OMG Roofing Products,

Contractor Restores the Roof on the Museum Beneath St. Louis’ Historic Gateway Arch

Western Specialty Contractors restored the roof of the Museum of Westward Expansion located beneath the Gateway Arch in St. Louis. This photo shows the protection board being installed prior to adding the leak detection system.

Western Specialty Contractors restored the roof of the Museum of Westward Expansion located beneath the Gateway Arch in St. Louis. This shows the protection board installed prior to adding the leak detection system.

The St. Louis branch of Western Specialty Contractors recently completed a project to restore and waterproof the roof of the Museum of Westward Expansion located beneath the iconic Gateway Arch on the St. Louis Riverfront. The work is part of a multi-phase project, spearheaded by nonprofit organization CityArchRiver Foundation, to expand and renovate the underground museum, plus renovate the grounds surrounding the Arch. The Jefferson National Expansion Memorial, which includes the Gateway Arch, Museum of Westward Expansion and the surrounding park, is maintained by the National Park Service.

Opened to the public in 1976, the Museum of Westward Expansion has undergone very few changes since its grand opening. The size of a football field, the museum features rare Native American Indian artifacts and materials documenting the days of Lewis and Clark and the 19th century pioneers who shaped the history of the American West.

Work on the 100,000-square-foot museum roof project began with removing sod and sandy soil covering the top of the roof and 10-28 inches of Elastizell engineered fill using a bulldozer. Next, the existing waterproof membrane was removed from the structural concrete deck.

After two layers of modified bitumen sheet waterproofing were installed, crews apply a coat of adhesive to adhere the asphaltic protection board.

After two layers of modified bitumen sheet waterproofing were installed, crews apply a coat of adhesive to adhere the asphaltic protection board.

Once the deck was exposed, Western crews went to work identifying and repairing leaks in the existing museum lid that had been present for many years, as the existing waterproofing had exceeded its lifespan. Several methods were used to evaluate the condition of the structural concrete deck, which included a chain-drag sounding along with visually identifying delamination and cracks.

Western crews then installed a two-ply Laurenco modified bitumen sheet waterproofing system covered with WR Meadows PC2 protection board. An electronic leak detection system followed by a permanent leak detection grid system were installed over the protection board. Crews then installed a layer of 1-1/2 inch, 60-psi Dow extruded polystyrene with an additional layer of the protection board and a J-Drain 780 drainage mat.

The next phase of the project involved waterproofing the 42,000-square-foot horizontal lid and the 37,000-square-foot vertical walls of the museum addition. Western’s scope of work in this area included installing a two-ply modified bitumen sheet waterproofing and protection board, as well as an electronic leak detection system, along with two layers of extruded polystyrene. A layer of extruded polystyrene was also installed on the vertical walls, followed by the drainage mat on both the horizontal and vertical walls.

During portions of the project Western crews were working over occupied space, as the museum was largely operational during construction.

During portions of the project Western crews were working over occupied space, as the museum was largely operational during construction.

Additional waterproofing of the north and south museum entrances encompassed approximately 13,800 square feet, which included approximately 5,000 square feet of deck around each leg of the Arch.

The museum was largely operational during construction, and for much of the project Western crews were working over occupied space. The company sequenced the removal of existing roofing material so that they could remove, clean and install new roofing material daily to keep the museum dry during construction.

Testing was a daily requirement during the waterproofing installation. Western was required to complete a pull test for every 500 square feet and take moisture readings for every 100 square feet. Daily observation reports had to be completed during the waterproofing application, with all testing results and location tests documented along with the weather conditions. Additionally, Western crews took 50 photos daily to document the testing and work area.

Construction on the Arch grounds began in August 2013, while renovations to the museum and visitor center began in April 2015. The multi-phase project is still underway, and the improved underground Museum of Westward Expansion is expected to be finished by summer 2018.


Roofing Contractor: Western Specialty Contractors, St. Louis,


Waterproofing System: Laurenco Waterproofing,
Protection Board: WR Meadows,
Extruded Polystyrene: Dow,
Drainage Mat: J-Drain,

Dow Building Solutions Celebrates 75th Anniversary of STYROFOAM Brand XPS Insulation

Dow Building Solutions (DBS), a business unit of The Dow Chemical Co., is celebrating the 75th anniversary of STYROFOAM Brand XPS Insulation, which has continued to facilitate sustainability, innovation and community success in the building and construction industry since its discovery in 1941. Dow marked the anniversary while attending the 2016 NAHB International Builders’ Show, a large annual light construction show that brings together the industry’s important global manufacturers and suppliers.

Builders today face a bewildering number of products and technologies promising better building performance. Dow’s portfolio-based approach offers solutions for the entire building envelope, offering energy efficiency that can stand the test of time. STYROFOAM has a long and rich heritage as a sustainable building product, insulating to meeting core thermal, moisture, air and vapor performance requirements through its rigid foam board technology. Over its lifetime, STYROFOAM can help save more than 30 times the energy embodied in it.

STYROFOAM has been part of Dow’s commitment to sustainable chemistry innovations for the last 75 years and will expand this legacy well into the future through continual optimization of building energy efficiency and performance. Dow has been a proud national insulation partner of Habitat for Humanity, with STYROFOAM donations leading Dow’s pledge to the address the need of affordable housing around the globe. More than 2,500 Habitat for Humanity builds in 2015 used Dow products to help homeowners reduce their home’s overall natural gas and electricity usage.

“New possibilities for resilient, energy-efficient and well-designed homes and buildings are being realized in neighborhoods and communities around the world thanks to imagination, science and engineering,” says Tim Lacey, global business director for Dow Building Solutions. “We are proud to offer 75 years of product innovation that addresses the need for long-term value as a sustainable building solution and look forward to improving, innovating and perfecting building envelope science well into the future.”