Manufactured in the U.S., the tile features a turf surface that looks like real grass. It measures 24-inches-by-24-inches and is 2.5-inches thick. Turf Tile can be used inside or outdoors on playgrounds, patios, or rooftops. Installation is completed using PlayGuard’s Quad Blok interlocking connectors, which feature openings that interface with the corner leg understructure PlayGuard tiles.
In response to customer preferences, Porous Pave Inc. has changed the standard size range of the recycled rubber chips in its surfacing material from 1/4-3/8 inch to 1/8-1/4 inch. The smaller, fine-cut rubber chips provide a more refined, smoother paved surface. An eco-friendly green building material made in the U.S., Porous Pave is a highly porous, durable and flexible pour-in-place permeable paving product. The XL formulation consists of 50 percent rubber chips and 50 percent stone aggregate with a moisture-cured, liquid binder. The XLS formulation is made with 100 percent rubber chips.
“We saw the need for a smoother finish based on comments and suggestions from landscape architects, hardscape contractors, homeowners, and facility managers,” says Dave Ouwinga, president, Porous Pave Inc. “We have worked with rubber-aggregate permeable surfacing for more than a decade. When our testing verified that smaller, 1/8 -1/4 inch rubber chips would not compromise our high standards for porosity and permeability, we adopted the fine-cut chip as our new standard.”
Discarded tires, saved from landfills and recycled, are shredded and processed into rubber chips for Porous Pave. With 27 percent porosity, Porous Pave made with the fine-cut chips retains 93 percent of the porosity and permeability of the product made with the traditional larger size. Porous Pave Inc. and its distributors will continue to supply the bigger chips for extensions of existing installations, as well as for new projects, with a minimum size of 5,000 square feet, where a slightly coarser, higher traction finish with 29 percent porosity is preferred.
Porous Pave XL, the formulation with the 50-50 rubber chip and aggregate mix, is a heavy-duty material poured in place at thicknesses of 1 to 2 inches over a compacted aggregate base of 2, 4 or 6 inches, depending on the application and required compressive strength. It retains stormwater on site by allowing rain and runoff to drain directly through its entire pervious surface, filter down into the aggregate base, and then slowly seep into the soil below. XL is used for loading docks, parking lots and driveways, building entrances and courtyards, patios, footpaths and walkways, golf cart paths, and tree surrounds that require a strong, durable, slip-resistant and permeable surface.
With 100 percent recycled rubber chip content, Porous Pave XLS permeable surfaces are more impact absorbing. XLS is a good option for pool surrounds, as well as school and public park playgrounds. Its light weight makes it ideal for rooftop applications, such as patios and pavement borders on green roofs.
Commercial office properties have always had to contend for tenants as a part of doing business and, increasingly, existing buildings are facing stiffer competition from new office properties offering integrated amenities packages that go way beyond the lobby coffee shop. As a new generation of employees enters the workforce, employers are challenged to secure leases that provide more than simple office space, instead offering an attractive combination of recreation, retail and relaxation options that feel more akin to a resort than a workplace. In the case of Prudential Plaza, a 41-story structure in Chicago built in 1955, the challenge for the building owners was to offer new value in a building originally designed to respond to a workforce that no longer exists.
Investing more than $85 million into building renovations, Prudential Plaza’s owners envisioned a top-to-bottom rehabilitation, crowned by a 13,000-square-foot amenities deck on the 11th floor. The rooftop transformation is highlighted by a fully wired amphitheater, fire-pit lounge and a small lawn accompanied by a new 12,000-square-foot fitness center and a 7,000-square-foot clubhouse located inside. These amenities are exclusively for building tenants and their employees. Kyle Kamin, a Los Angeles-based CBRE Inc. executive vice president and tenant broker who has clients in Prudential Plaza called the roof deck “a game-changer with an unbeatable view.”
Certainly the idea of a gorgeous tenant recreation and lounge area would appeal to most; however, few outside of the design and construction industry would appreciate the immense challenge of adding this type of space on top of a 60-year-old roof. When Wolff Landscape Architecture, Chicago, was asked to partner with Chicago-based architecture firm Solomon Cordwell Buenz for landscape design, project manager Ishmael Joya quickly understood the complexities of the situation. Joya is a landscape architect with 15 years’ experience, specializing in green-roof construction.
“Prudential Plaza is a classic figure in Chicago’s skyline and the first time we walked the project it was clear that the 4 1/2-inch-thick roof deck was going to present some design and construction challenges,” Joya remarks. Although the Wolff Landscape Architecture team has completed many green-roof projects, including renovations, Joya realized that adding what is essentially a mini-park to a very thin structural surface was going to require out-of-the-box thinking. “In any roof-deck renovation, it’s critical to reduce the weight of the building materials because the building is only designed to support a maximum amount of weight and that can’t be compromised,” he says.
Joya worked closely with the design team’s structural engineer, Wiss, Janney, Elstner Associates Inc., Chicago, to make sure the appropriate products were specified to support the expected weight of each area of the renovation
Demolition and Interim Roof
Like many large-scale occupied renovation projects, Prudential Plaza’s overall renovation was executed in multiple phases, allowing construction activities to take place while tenants maintained their typical routines. Romeoville, Ill.-based Preservation Services Inc., a commercial roofing company, was responsible for rehabilitating the original 11th-floor roofing structure. The original roof was a modified bitumen membrane that had been applied directly to a layer of lightweight concrete and covered by 2- by 2-foot pavers. Preservation Services carefully removed the pavers, old membrane and thin layer of concrete.Because the building is located adjacent to a series of vaulted streets, the construction team was unable to use a high-reach crane because the weight of the crane would have required special provisions and necessitated street closures. Consequently, crews carried all removed debris down through the freight elevators during the night while the building was largely empty. At the end of each night, a single-ply EPDM membrane was rolled out, seamed and secured to protect the under structure from possible water penetration the next day.
Once demolition was complete, the EPDM was opened in select areas so repairs to the concrete slab could be made by other trades. When repairs were complete, a single layer of torch-applied modified bitumen membrane was applied to the deck along with additional structural steel required to support the added weight of trees, planters, patios and people. Finally, a white, granular-surfaced modified bitumen roof over tapered isocyanurate foam insulation was installed making the undersurface ready for the plaza deck renovation work.
Joya recommended a lightweight expanded polystyrene (EPS) material with high compressive strength that is used to reduce axial loading on structures. He has found the product very easy to work with, which saves time and money, ultimately allowing designers to put more of the client’s investment into tangible value users will see and feel rather than subsurface building materials.
On the Prudential Plaza roof-deck renovation, two types of EPS were used. EPS 15 was used in areas that would largely be filled with plants and wouldn’t bear much foot traffic. EPS 46, chosen for its high compressive strength, was used as a structural fill across the design’s many grade changes and in areas that would bear more weight of roof-deck occupants. For Joya, another advantage of using the EPS is being able to see the shape of the assembled product and make any required changes before the concrete is poured and work becomes significantly more complicated.
PHOTOS: Wolff Landscape Architecture
How much traffic can a roof system bear? The fact is, live loads on roofs are getting much bigger as building developers and owners seek to allow more indoor-outdoor uses and rooftop amenities, such as seating areas, gardens and even fire pits and pools, which draw people to the roof. Plus, the dead load may be increasing thanks to those living material installations, such as planters and vegetative roof gardens. These assemblies usually require or hold water—adding to the dead load—as well as frequent maintenance and inspections, which mean a few more people (and more live load).
“We’ve known the benefits of a green roof from a water-management point of view for some time,” says Joshua Zinder, AIA, principal of JZA+D, Princeton, N.J., noting that more than 70 percent of the water that hits the roof is absorbed. “Increasingly, we see the roof as an opportunity for generating revenue or enhancing the value of the building. One of the ways we’re now helping developers reposition older office and industrial properties is by determining if we can create roof farms or indoor-outdoor spaces not only on the ground floor, but also on the roof planes.”
The case of the rooftop garden with public access is a growing trend, too, and “one must ensure that the roof structure has the necessary structural capacity to support rooftop activity,” notes Kelly Luckett, author of Green Roof Construction and Maintenance. Local codes vary for live loads and dead loads, he explains, and the project team calculates the green roof assembly as part of the total dead load. “Water in excess of that which saturates the growth media, snow and people visiting the green roof are all considered part of the live load of the structure,” Luckett adds.
Just as important, the roofing system has to resist the wear and tear of the live loading. The three main concerns for exposed structural elements, such as roofs, balconies and terraces, are protection from weathering, water ingress and environmental damage. Pedestrian walkways must also ensure long-term durability.
A look at the latest trends in “activating rooftops” reveals even more reasons for roofing contractors, architects and facility owners to look more carefully at specification documents and installation methods for these live-load roof zones.
Skylife and Community
For residential projects with rooftop terraces, careful specifying and installation of green roof assemblies is critical. “We like using liquid membrane roof and extensive green-roof systems, such as sedum carpet,” says Andrew Franz, AIA, LEED AP, principal of Andrew Franz Architect PLLC, New York, adding that the systems work well because the drainage mat is modular, lightweight, and easy to install and adjust—something that is important on uniquely shaped urban rooftop terraces.
Recent projects by Franz include a 2,800-square-foot garden terrace for a family of four in Manhattan. A bluestone floor extends from the dining area to the terrace’s softscape herb garden, further blurring the boundary between in-doors and out. “The green roofing system also includes a protection mat, which protects the roof membrane, a filter sheet of very lightweight soil to protect the drainage mat and the sedum carpet,” Franz says.
Other recent projects with active green roofs demonstrate the benefits of strong PVC membranes, such as at the modern 93 Bright Street townhouse in Jersey City, N.J., designed and developed by Jorge Mastropietro, AIA, whose firm JMA is based in New York City’s Soho neighborhood. Another example, called Trouthouse, designed and built by the Brooklyn-based thread collective, is a showcase of “passive design” principles that reduce energy use, recapture water and even allow for a roof-mounted shade structure that doubles as photovoltaic panels.
The new LEED Gold-certified facility for Gateway Community College in New Haven, Conn., was designed with a vegetative roof to create a new community area on the top floor. According to construction manager Providence, R.I.-based Dimeo Construction, which worked with Providence-based Gilbane Building Co. and the New York office of architect Perkins+Will on the project, the “multi-level student gathering area steps up from the ground floor to a rooftop garden. The green roof also supports photovoltaic panels on a special framing system.”
“We engineered Porous Pave with greater permeability per square foot than other permeable and pervious paving materials,” says Dave Ouwinga, president, Porous Pave Inc., the product manufacturer. “It can therefore achieve stormwater retention goals with smaller installations, saving money on materials and labor.”
“The recycled rubber in Porous Pave, processed from reclaimed scrap tires, imparts flexibility, so in contrast to concrete and asphalt, Porous Pave withstands freeze-thaw cycles without heaving or cracking,” says Jim Roth, president, Porous Pave Ontario, a Canadian distributor of the product. “The rubber content also makes it slip-resistant.”
Porous Pave Ontario entered the product in the IIDEXCanada Innovation Awards competition. Organized by IDC in 1984, the annual awards celebrate innovation in product design and exhibit creativity.
A panel of IDC members, who are all registered interior designers, judge product entries based on design objectives, design and technical innovation, market application, and sustainability. Entries are scored on a 0-100 scale, with Gold-level awards requiring a score of at least 90. Only five of the 30 product winners, including Porous Pave, attained the Gold standard. Among this year’s winners, Porous Pave was the only outdoor product for landscaping, hardscaping and on-site stormwater management applications.
The IIDEXCanada award is Porous Pave’s second honor this year. BUILDINGS magazine selected Porous Pave as a 2015 Money-Saving Product. Porous Pave was one of the superior building products showcased for commercial building developers, owners and facility managers in the magazine’s June 2015 issue.
Since performing its first concert in 1939, the West Michigan Symphony, a professional orchestra in Muskegon, Mich., has been a vital part of the region’s cultural landscape. In spring 2013, the symphony decided it was time to expand its administrative and ticketing services. It moved into offices in the newly renovated Russell Block Building. Located in downtown Muskegon, a block away from the Frauenthal Theater where the orchestra performs its concerts, the historic Russell Block Building was constructed in 1890.
“With the move, the symphony also realized a long-held dream: establishing a flexible space where we could expand educational offerings and stage smaller fine-arts performances,” explains Carla Hill, the symphony’s president and CEO.
Named The Block, the 1,800-square-foot space offers seating on two levels for up to 150. In addition to providing an intimate venue for a variety of arts performances, The Block is available for meetings and special events. The west-facing windows of The Block look out toward Muskegon Lake. However, there was a problem: Outside the windows, an unimproved and unappealing tar roof marred the view.
“In conversations with the symphony and Port City Construction & Development Services, which planned and managed the building renovation, we started envisioning the transformation of the unadorned roof into a rooftop patio and garden,” says Harry Wierenga, landscape architect, Fleis & VandenBrink Inc., Grand Rapids, Mich.
Wierenga designed a 900-square-foot green roof (including 380 square feet of vegetation and a 520-square-foot patio area) as an accessible and appealing outdoor space. His design invites patrons of The Block to the outdoors onto a landscaped rooftop patio.
First Things First
“The existing roof was a tar roof over a concrete deck. Some holes had been boarded over and patched with tar,” notes Gary Post, manager, Port City Construction & Development Services LLC, Muskegon. “If the rooftop patio and garden had not been incorporated into the project, we would not have replaced it. We had to reroof to support the new rooftop outdoor space.”
The Port City Construction & Development Services roofing crew removed the existing roof down to the concrete deck, which they repaired. Two new roof drains were added to improve drainage. A single-ply membrane was selected for the new roof. The crew fully adhered the new membrane to the deck. The crewmembers then installed a geotextile fabric to protect the membrane and rolled out a geotextile drain sheet atop the protection fabric. The drain sheet facilitates drainage to the existing and two added roof drains.
A new 40-inch-high wall around the perimeter was constructed to shelter the space and enhance rooftop safety. Preparations also included widening the opening out to the rooftop from the interior of The Block. Glass double doors would be installed to establish a generous and transparent transition from indoors to outdoors.
The project team applied a multi-faceted set of factors in evaluating options and selecting a pavement material for the patio:
- To eliminate standing water and allow excess stormwater to flow to the drains, the paving material had to be permeable.
- The plan called for installing the patio and green-roof elements on top of the geotextile drain sheet. The paving material would have to work with the modular green roof selected for the project.
- The paving material had to be lightweight. By regulation, the maximum static plus live load for the roof is 100 pounds per square foot.
- For easy access and safety, the pavement had to be low profile to minimize the threshold at the entry into The Block.
- To create visual interest within the rectangular shape of the roof, the design emphasizes irregular shapes with angles to break up the space. The paving material would have to be flexible to adapt to the design.
- The musical-note motif Wierenga envisioned for the patio is the quintessential design element for the entire rooftop project. The paving material had to offer the versatility to express the design.
- Finally, a green-building product was preferred.
The project team considered composite decking and pavers. However, these linear materials were not flexible enough to adapt to the shape of the patio or sufficiently versatile to convey the musical note design.
PHOTOS: Porous Pave Inc.