Patios, Walkways, and Driveways Made of Porous Pavement
To help reduce surface runoff, consider using permeable pavers — porous pavement — instead of old-fashioned concrete.
Although concrete lasts a long time — creating durable patios, driveways, roads, and foundations for houses — the production of concrete takes a lot of energy. And that's not the only problem with concrete: Whenever the ground is covered with it, rain doesn't seep into the soil. As the rain accumulates and water starts flowing off the concrete, it can create problems. But porous pavement materials are now available to provide a solid base and still allow water to seep through.
Benefits of Permeable Pavers
Groundwater is a source of drinking water for many people. It also nourishes deep-rooted plants and trees. Replenished by rain and melting snow, groundwater has become an endangered resource, partly because of the impermeable materials used in new developments in and around cities and towns. Roofs, roadways and runways, parking lots, driveways, sidewalks, patios, and tennis courts prevent surface water from seeping into the ground.
These impervious surfaces often divert water into storm sewers and then into streams. The rush of water may result in costly and sometimes life-threatening floods. Surface runoff also carries toxic pollutants, such as chemicals and oil from paved roadways and parking lots, into rivers, lakes, and reservoirs, where it pollutes drinking water supplies and harms wildlife.
Another problem caused by so much paving is the buildup of heat in and around cities and towns. Asphalt and concrete absorb sunlight and convert it to heat. The buildup of extra heat around cities and towns is known as the "heat island effect."
Next time you build a patio, walkway, parking space, or driveway, you can address these problems by installing permeable materials, some of which allow grass to grow in them. Many attractive options will permit water to drain into the ground. Some even reduce heat accumulation around buildings.
What Are Your Options?
Personalize your driveway by adding a border, accent or custom design! Cambridge pavers are ideal for creating these types of applications. We even offer luminescent NighTec™ pavers which are visually appealing and practical for parking at night.
When replacing or creating a driveway or parking area, consider either permeable pavers or open-cell concrete blocks. These blocks are designed to support vehicles, but are sufficiently open to allow water to drain through them. The spaces are filled with gravel or sand. Grass or low ground cover can grow in the open spaces, which helps reduce heat buildup.
Another product that can be used for driveways is pervious concrete, aka porous pavement. As its name implies, this is a highly porous form of concrete. It's made from aggregate (small stones) and cement, which binds the aggregate together. However, unlike conventional concrete, pervious concrete contains little, if any, sand. This results in a substantial number of open spaces in the concrete, basically a lot of holes through which water can flow into the ground.
Porous pavement is recommended by the U.S. Environmental Protection Agency and geotechnical engineers across the country to help manage storm water runoff.
Installation of all porous paving is straightforward and can be done by relative novices. However, professionals will often do a better job and complete the work faster because they have the right tools and equipment. Professionally installed driveways, walkways, patios, and other structures also may last longer, making them worth the extra initial investment.
All of the products described here require excavation by hand or machine. They all start with a 6- to 8-inch-deep bed of sand or gravel, carefully leveled. If you install a system of pervious pavers or the Grasspave2 or Gravelpave2 yourself, be sure to read and study the manufacturer's specifications, and follow the instructions carefully. When in doubt, call in an expert for consultation, or call the manufacturer and talk to its customer installation support staff.
Bear in mind that you also may need to obtain a building permit, so check with the local building department before you purchase materials.
Ready to start with your new driveway?