Porous Pave Refines Texture and Appearance of Permeable Paving Product

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.

A Permeable Pavement Patio Outside a Performance Space Features a Distinctive Musical Note Pattern

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.

The porous-paving material had to express the musical note motif the landscape architect envisioned for the patio. It is the quintessential design element for the entire rooftop project.

The porous-paving material had to express the musical note motif the landscape architect envisioned for the patio. It is the quintessential design element for the entire rooftop project.

“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 shelters the space and enhances rooftop safety. The porous paving’s gray and black custom-color mix harmonizes with the color of the wall.

A new 40-inch-high wall around the perimeter shelters the space and enhances rooftop safety. The porous paving’s gray and black custom-color mix harmonizes with the color of the wall.

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.

Permeable Pavement

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.

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