The USGBC’s LEED BD+C Reference Guide describes many applications for pervious pavement, including aiding in credits for Stormwater Design, Quantity Control (SSc6.1), Quality Control (SSc6.2), Protect or Restore Habitat (SSc5.1), Maximize Open Space (SSc5.2), and Heat Island Reduction, Nonroof and Roof (SSc7.1, 2) by improving infiltration, minimizing building impact on the natural environment, and providing a drivable, structural surface that doesn’t absorb and hold heat from the sun.

According to the PCA and NRMCA, “by capturing stormwater and allowing it to seep into the ground, porous concrete is instrumental in recharging groundwater, reducing stormwater runoff, and meeting U.S. Environmental Protection Agency (EPA) stormwater regulations”.

The Soil Retention company out of Carlsbad, CA, offers a number of products that qualify under the category of pervious pavement. Today we’re focusing on one of the first to capture my attention, Drivable Grass (see, even the name is intriguing at first read!)

Soil Retention started in 1987 with a license to distribute Loffelstein (a porous, cementous material) block throughout Southern California, Arizona and Southern Nevada. The company’s various product offerings today are due to owner Jan Erik Janssons’ constant diligence and dedication to improving upon the loffenstein product with modifications to more effectively fit various market segments. The evolved and improved products were patented and trademarked as Verdura ("Verde" for green and "Dura" for durable) products.

Drivable Grass is an engineered grid system that allows the product to flex and conform to irregular ground surface contours while providing the intended structural support. Originally it was designed to be used in place of concrete or asphalt driveways, patios, emergency and service vehicle access lanes, and parking areas for cars, RVs and boats (but is applicable for any area where a permeable or vegetated surface is desired for aesthetic or sustainable reasons, but where underlying structure is a necessity).

Drivable Grass also makes an environmentally friendly solution to bioswales, v-ditches and roadside swales and maintains its load supporting characteristics even when saturated. The product’s geometry allows for enhanced root penetration, infiltration of storm water, and minimization of site runoff.

The product comes in 24”x24”x1.5” mats, and installation only requires a compacted sub-grade and base, 1.5” bedding (80% well graded sand/20% organic material), backfill and infill (though obviously consultation with a civil or geotechnical engineer is recommended/necessary). The mats currently are available in three colors: buff/tan, grey and terracotta, though other colors are available via special order.

I’m seriously considering putting in some for a future driveway project at my home… with benefits as numerous as low impact development, recommended best management practices, durability, strength, flexibility, bio-filtration, site permeability, superior root penetration, lower runoff, reduction in heat island, limited excavation, and easy installation, how could I not? They even have do-it-yourself installation instructions and specifications for home owners available at the Soil Retention website, (where they also have specifications for construction professionals and a detailed product brochure).

 

This product may contribute to earning points for the following LEED BD+C credits:

Sustainable Sites Credit 6.1: Stormwater Design, Quantity Control
Sustainable Sites Credit 6.2: Stormwater Design, Quality Control
Sustainable Sites Credit 5.1: Protect and Restore Habitat
Sustainable Sites Credit 5.2: Maximize Open Space
Sustainable Sites Credit 7.1: Heat Island Reduction, Nonroof
Sustainable Sites Credit 7.2: Heat Island Reduction, Roof

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