Manage stormwater runoff with ‘permeable’ concrete patio pavers

Looking out your back window during a heavy rain one day, you’re shocked to discover that instead of gazing upon your nice patio, you’re staring at a small lake. Water is ponding two inches deep already — and the storm is far from over.

It’s a sight many D.C.-area homeowners have seen, whether during a long deluge like the one we got from Hurricane Sandy, or simply from a brief but powerful summer thunderstorm. Managing stormwater runoff is a year-round challenge here in the Mid-Atlantic region. But you don’t have to settle for standing water on your patio.

We recommend looking at two issues to address the problem. One is proper grading. If your patio has been around a good many years, the soil underneath it is bound to become uneven over time. Tree roots, normal wear and tear, and other factors will cause the soil beneath your patio to shift. Those changes will likely not be uniform, either, with some spots sinking while others get pushed up.

One solution: re-grading the patio. This involves removing the pavers — bricks, flagstones, etc. — and excavating the soil from your patio down to a certain depth. The depth will depend on what type(s) of soil you have, what type(s) of pavers you’re using, your yard’s drainage patterns, and other issues.

After the area is evaluated and excavated, new soil — or a combination of aggregates, sand and gravel or top soil — gets layered in, leveled, compacted, and graded to allow for efficient vertical and horizontal drainage.

Another solution: ‘permeable’ concrete patio pavers. These are pavement systems that — together with very specific paver joint widths, sublevels of prescribed bedding material, and specialized construction methods — allow water to infiltrate between the pavers, filter down into courses of bedding, base and subbase material, and drain down into natural groundwater flows.

The Interlocking Concrete Pavement Instituteoffers a good basic video about permeable paver systems on YouTube. Of course, Johnson’s Landscaping Service, Inc. and ICPI trained and certified firm, is always available to consult with you when you’re ready to reclaim your patio from Mother Nature. Contact us.