It’s becoming harder and harder to get the hardscape you want. With stricter permitting requirements in many areas, several proposed projects are being rejected in order to mitigate stormwater runoff and protect existing structures. Fortunately, there may be a perfect solution to your problem: permeable pavers.

So, why should you consider permeable pavers for your next project? More importantly…what are they

What Are Permeable Pavers?

Permeable pavement allows water to pass through the surface and back into the ground. With all of the permitting requirements in place regarding stormwater runoff, permeable pavers are a way to get that stunning driveway, walkway, or patio while still abiding by the code.

How Do They Work?

All concrete pavers have lugs: essentially a built-in spacer. These lugs keep a consistent gap between each paver, creating an interlock between each piece. 

Permeable pavers have larger lugs, creating a bigger gap and allowing water to run down through the joints.

How Does The Installation Method Differ?

The installation method is different from a standard paver. In this case, we’re looking to create a void space in the base to allow for the storage of water. To allow for this, the excavation needs to be deeper than a standard installation to allow for the various layers of stone to be installed.

A standard paver installation calls for 6″ of ¾” modified stone and 1″ of sand. The pavers are laid atop this bed for a total excavation depth of 9″. Since modified stone is ¾” and finer, it compacts into a dense base that allows very little water to move through it. Finish that project off with polymeric sand between the joints, and 95% of water falling on a standard paver install will run right off.

Typical Installation Cross Section - Non Permeable Pavers

Typical Installation Cross Section of Non-Permeable Pavers

Typically, for porous pavers there are at least 6″ of #2 stone in the base, 4″ of #57 stone on top of that, and 1½” – 2″ of #8 stone used for the setting bed. The pavers are laid on this bed, and then more #8 stone is swept into the joints. This leaves a minimum excavation depth of 14″. All of this stone is considered “clean stone” so water passes through it easily. The depth of the base is the only limiting factor in how much water the area will store.

Permeable vs Non Permeable Pavers

Typical Installation Cross Section of Permeable Pavers

Why Are Permeable Pavers The Right Choice For Me?

More excavation and more stone are required for permeable pavement. So why consider it as an option?

An increasing number of townships are requiring that you mitigate any additional runoff being generated by an increase in impervious surfaces. The mitigation could come in the form of rain barrels, seepage beds, or permeable pavement.

Quite frankly, most people don’t want rain barrels set up all around their house, and even if they don’t mind, the chances that they will use the water captured in them is slim.

A seepage bed is essentially a hole dug in the ground and filled with large stone, with downspout pipes run out to the bed to capture roof water and return it into the soil. Seepage beds can become costly, especially if it has to be designed by an engineer.

The decision of which route to take is up to you. There are applications where some of these choices should be used, and some where they should be avoided unless other measures are taken.

Permeable pavers just might be the right choice for you. Contact Garrett Churchill today for more information.

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Andy Sykes

Andy Sykes is the owner of Garrett Churchill Inc.