Permeable paving includes any paved surface with small openings that allow water or air to pass through. With traditional pervious paving, storm water runoff contributes to erosion and water pollution. Permeable paving helps to reduce these issues and protect the environment by slowing the flow of storm water. Instead of running across the surface, storm water instead passes through the openings in the paved areas. The underground soil naturally filters out pollutants, leaving the filtered water free to follow underground channels on its way to replenish local water bodies.
Porous concrete represents one of the most versatile types of permeable paving. Compared to traditional concrete, porous concrete contains more water and larger pieces of gravel. This creates a porous, open surface for water to pass through. When prepared by a qualified installer, permeable concrete is often strong enough to serve as road paving material. Its light surface also helps to reflect, rather than absorb, the sun's rays, leading to cooler temperatures in paved areas.
Porous asphalt serves as another form of permeable paving, though it is typically not appropriate for roads. Installers eliminate the sand from the asphalt mixture and use a large, uniform type of gravel to create a porous surface. This form of paving is best-suited to light traffic situations, such as parking lots or walkways.
Block pavers are another form of permeable paving, and serve as one of the most versatile options for storm water control in paved areas. Interlocking pavers provide a high level of structural support, and can be used in driveways, patios, or walkways. The space between these paving stones allows storm water to reach the soil with ease, allowing for quick filtering.
Grid or lattice paving systems offer an innovative and eco-friendly method of creating driveways and parking lots. Installers start by laying out stone grids over a base of gravel or sand. In some cases, heavy-duty plastic grids have taken the place of these stones. Over time, grass grows through the holes in these stones or plastic, creating a turf-like area. This type of paving creates enough strength for vehicle traffic while maintaining a green appearance.
For one of the easiest and most affordable permeable paving options, installers often turn to loose gravel with no binding agent. This type of paving allows large volumes of storm water to pass through with ease, and is very easy to install and maintain. Gravel paving is best-suited to low speed areas like parking lots or walkways.