Advanced Polymers for the Manufacturing of TPO Membranes

Dow’s portfolio of materials for roofing membranes features advanced polymers for thermoplastic polyolefin (TPO) systems. These proven, highly respected solutions can help manufacturers develop custom-tailored formulations that fit specific designs, production processes, and end-use requirements. With several advantages over incumbent materials, ENGAGE TR Polyolefin Elastomers (POEs) represent the company’s current state-of-the-art for TPO-based membrane formulations. According to the manufacturer, ENGAGE TR POEs offer an ethylene-based solution that has inherently better longevity, and can be formulated to produce membranes with significantly improved flexibility and broad welding window. The unique design of ENGAGE TR also allows increased filler loading, which can, in turn, be used to improve fire performance.

According to the manufacturer, in a comparison of formulations based on a typical polypropylene (PP) TPO and ENGAGE TR, the Dow material offers:

  • 40 percent lower modulus for increased flexibility and ease of installation
  • Reduced glass transition temperature (Tg) for better low temperature toughness
  • Excellent thermal stability which can help deliver better property retention over time

Membranes formulated with ENGAGE TR POE offer increased weatherability/UV resistance, according to the company. Scanning electron microscope (SEM) photography taken after 10,000 hours of accelerated weathering reveals surface cracking in the PP TPO-based membrane. In sharp contrast, the ENGAGE TR POE-based membrane remains crack free at the same stabilizer package. This indicates higher levels of UV and weather resistance, which correlate to longer service life. Better UV resistance is expected for a polyethylene based chemistry thanks to the lack of tertiary carbon which is intrinsic to PP and prone to chain scission.

According to the company, whether you’re working with TPO-, PVC- or EPDM-based systems, Dow’s roofing membrane science can offer:

  • Flexibility that lasts, even in thicker sheet installations
  • Long-term durability
  • Weatherability/UV resistance that meets or exceeds appropriate industrial standards
  • Fire performance with halogen-free, low-smoke, low-ignitability, and low-fuel load options
  • Light color/cool roof formulations to reduce heat absorption
  • Multiple attachment options, including fully adhered, heat welded, mechanical, and/or ballasted systems

For more information, visit www.dow.com.

Firestone Building Products Aids Official Carbon Partnership Between Dow and the IOC

Marking the first carbon mitigation project in North America under the Official Carbon Partnership between Dow and the International Olympic Committee (IOC), Dow announced its collaboration with Firestone Building Products, a subsidiary of Bridgestone and a manufacturer of commercial building performance solutions. The collaboration is supporting the creation of an energy modeling tool to accurately describe reductions in cost, energy and greenhouse gas (GHG) emissions of commercial structures that use innovative polyurethane roofing insulation from Firestone Building Products. This insulation, developed by Firestone and enabled by Dow’s polyurethane raw materials, addresses low-temperature thermal drift without compromising the other performance metrics. 

“With cities growing at a rapid pace, it is paramount that we as an industry evaluate and implement innovative new materials to accelerate the adoption of solutions that mitigate greenhouse gas emissions in the infrastructure market segment,” said Dr. Nicoletta Piccolrovazzi, circular economy market director for Dow and global technology & sustainability director for Dow Olympic & Sports Solutions. “Firestone Building Products shares our vision, and enabled by the Dow-IOC Official Carbon Partnership, we’ve embarked on a mission that will empower architects, contractors and building owners to better identify energy saving solutions and improve decision-making, doing their part to create a low-carbon legacy.”

The new energy modeling tool – to be available on Firestone’s website in 2020 – is being developed by Oak Ridge National Laboratory (ORNL) with funding support from Dow. With this new tool, commercial architects, property owners, roofing consultants and construction companies can scenario-test the potential long-term reductions in whole-building energy use and the associated GHG emissions resulting from installation of the ISOGARD newly-formulated Firestone polyurethane foam roofing insulation. Use-phase building energy consumption is compared within the modeling tool to alternative roofing technologies, allowing for informed selection of material and amount of insulation. This ability to compare performance will be particularly valuable for cold climate zones of the United States and Canada, where temperatures drop below 40 degrees Fahrenheit and older polyurethane foam formulations experience a drop in their insulation performance. 

“Partnering with Dow and working with ORNL to create a modeling tool will help to validate, quantify and reinforce Firestone’s commitment to sustainable building solutions,” said Taylor Cole, president, Firestone Building Products. “Sharing the tool on our website for everyone to use is just another way we’re working with industry partners to not only provide attainable solutions for our customers, but to also work together to do our part in reducing carbon emissions.” 

The new whole-building energy modeling tool will be used to further promote and advance the adoption of Firestone’s ISOGARD roofing insulation, enabled by Dow polyurethane raw materials. ISOGARD foam is formulated to retain more of its R-value (insulating value) at temperatures below 40 degrees Fahrenheit compared to existing polyurethane foams. This formulation is designed to create tighter building envelopes and improve building energy efficiency, without changing the installation qualities—such as thickness, compressive strength, weight, and dimensional stability—of the roofing boards. The formulation is estimated to increase the R-value of the roofing material from 5.5 to 6.3 per inch when tested at 40 degrees Fahrenheit and lower. For commercial construction trade professionals, this translates to improved energy savings and can contribute to obtaining Leadership in Energy and Environmental Design (LEED) certification.

This agreement is the second of several anticipated joint efforts that will result from the Collaborative Blueprint for unlocking carbon reductions announced last year by Dow. The first agreement was signed in April with PETRONAS Chemicals Glycols. The Blueprint underpins the Dow-IOC Official Carbon Partnership, initiated in 2017 to balance the operational carbon footprint of the IOC, and encourages organizations outside the Olympic movement to adopt programs for reducing carbon emissions while catalyzing change across value chains.  

For more information on Dow’s sustainability programs and the Dow-IOC Carbon Partnership, visit www.dow.com/en-us/sports/sustainability. For more information about Firestone Building Products, visit http://firestonebpco.com/.

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

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.”

TEAM

Architect: HOK, Chicago, www.HOK.com
General Contractor: James McHugh Construction, Chicago, www.McHughConstruction.com
Roofing Contractor: All American Exterior Solutions, Lake Zurich, Illinois, www.AAEXS.com
Landscape Contractor: Christy Webber Landscapes, Chicago, www.ChristyWebber.com

MATERIALS

Garden Roof System:
Cover Board: Securock Gypsum-Fiber Roof Board, USG, www.USG.com
Membrane: MM6125 hot rubberized asphalt membrane, American Hydrotech Inc., www.HydrotechUSA.com
Protection Sheet: Hydroflex 30, American Hydrotech Inc.
Root Barrier: Root Stop, American Hydrotech Inc.
Insulation: DOW Styrofoam, DOW Chemical, www.Dow.com
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, www.CarlisleSyntec.com
Cover Board: DenDeck, Georgia-Pacific, www.BuildGP.com
Attachment System: RhinoBond, OMG Roofing Products, www.OMGroofing.com

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.

TEAM

Roofing Contractor: Western Specialty Contractors, St. Louis, Westernspecialtycontractors.com

MATERIALS

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

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.”