Project Name: San Francisco Bay Peninsula Hillside Residential Driveway
Project Location: Woodside, CA
Building and maintaining a driveway on a steep slope can present some unique geotechnical challenges. With impervious pavements (concrete or asphalt) stormwater runoff can contribute to urban nonpoint sedimentation and pollutant loads, and high-velocity sheetflows can lead to erosion issues downslope and along pavement edges.
While sloped driveways are notorious for being more challenging to construct and manage than level driveways, sometimes they are the only option for homeowners. A homeowner living in the hills along the San Francisco Bay Peninsula sought a long-term solution to stabilize a 1,000-foot-long, sloping driveway, so they reached out to KC Paving (Redwood City, CA) for assistance.
Initially, the contractor considered using a flexible, rolled product along the surface of the hilly driveway; however, after reaching out to local material supplier, Reed & Graham, they determined that a more durable, rigid system would provide a better outcome.
After reviewing spec sheets, comparison charts, and material samples, the property owner chose the GEOPAVE® Gravel Porous Paver System.
Why Permeable Pavers Are Best for Stabilizing Steep Driveways
Stormwater will cascade down a steep driveway, making a permeable system the ideal solution to prevent erosion. The GEOPAVE system promotes a high rate of infiltration, limits runoff, and performs as a natural on-site retention system. This is possible because the system’s structural framework holds highly permeable, open-graded base course in place through a unique herringbone cell pattern and monolithic mesh bottom.
The GEOPAVE pavers’ interconnected cell walls spread point loads across the system with minimal flexing, eliminating the potential for concentrated rutting. Due to its shared wall system, strong U-Clip connectors, and load-spreading mesh bottom, the GEOPAVE porous paver system offers exceptional load transfer capability. With lower base requirements than rolled systems, the GEOPAVE system can accommodate HS25 loading with minimal excavation.
Installing Porous Pavers on a Sloped Driveway
Before installing the GEOPAVE pavers, the contractor re-graded the existing slope and installed concrete curbs and a retaining wall along the outside edges of the driveway. After regrading, a geotextile fabric was placed over the prepared surface and a layer of compacted rock was placed to establish a firm base beneath the GEOPAVE system.
The contractor’s previous experience with paving stones helped them easily understand the herringbone installation pattern of the GEOPAVE system, and the installation was completed ahead of schedule and on budget. The total square footage of the project came in at just under 20,000 square feet.
Following placement of the GEOPAVE system, the cells were filled with ½-inch black basalt washed chips. While any open-graded aggregate would suffice, the homeowner selected an infill material to achieve a customized appearance.
The GEOPAVE Gravel Paver System provided a smooth, clean driving surface free of rutting with a rural road aesthetic. It also offered an environmentally friendly alternative to a hard-paved surface, thereby eliminating the damaging effects of stormwater runoff and accompanying impacts from erosion and sedimentation.