The aggregate in the joints provides infiltration as long as it is not plugged.Ī periodic maintenance program is necessary for all three P’s to guarantee lasting stormwater conveyance past the paver layer. Water enters the joints between the solid impervious pavers and flows through the paver system. This type of system allows the movement of water and air around the paving material. Permeable is a term used to describe paving methods for roads, parking lots, and walkways. Permeable pavers are different from pervious and porous pavers in that rainwater passes around the paver opposed to through it. The pavers are separated by joints filled with crushed aggregate. Permeable pavers are composed of a layer of concrete or fired clay brick. This image, courtesy of ReadingRock Building Materials and Services, depicts permeable pavers. This stormwater conveyance process is referenced by some paver manufacturers as the “paver system.” All three types require a similar compacted stone aggregate layering process beneath the surface to accept the stormwater and create a “reservoir” prior to the water percolating into the sub-grade or being piped away.
![porus walker porus walker](https://cdn.shopify.com/s/files/1/0224/4516/2576/products/poohidiotsprint1_1200x.jpg)
With permeable pavers, water is circumvented around the paver, and the filtering process begins between the pavers in the void space filled with select aggregates. In the case of both pervious and porous pavers, this is partially achieved within the paver before water enters the layers below. The goal in using these types of pavers for stormwater control is to limit runoff at the source, reduce downstream erosion, and improve water quality by filtering pollutants in the substrata layers. Careful consideration of site characteristics and project objectives will enable the owner to minimize stormwater runoff and maximize the water quality benefits that these products provide. Each possesses certain physical and aesthetic qualities that need to be considered prior to project design and installation. There is an obvious and distinct difference between pervious, permeable, and porous pavers. Pervious, permeable, and porous pavers (the three P’s) often are used interchangeably by professionals without regard to their unique characteristics. Photo courtesy of Xeripave Super Pervious Pavers.
![porus walker porus walker](https://www.fortytwoshop.co.uk/wp-content/uploads/2019/08/Lakai-x-Porous-Walker-Newport-Hi-Splatter.jpg)
Xeripave, a pervious paver, used with permeable pavers.