Permeable Pavement Installation in Madison, WI

While installation of a permeable system is similar to other paver applications, there are some very important differences to make sure the system performs properly.  See our patio or driveway details for more standard installation practices.  

Elements of Permeable Pavement Construction

Base Layer

Permeable pavement systems require deeper excavation than traditional paved surfaces so we can create sub-surface areas for water to drain and collect. We are trying to create an underground water containment system, and we need more room to do so than we would in your standard backyard patio or even a standard paver driveway.   

To attain adequate depth, we excavate to accommodate 12-18 inches of compacted base material. This can mean excavating of up to 2 feet below the surface of your new pavers. Depth will vary based on how much water may be coming into the area (we will calculate this by measuring the drainage area).

Permeable pavement requires the use of several different sizes of aggregate for base material. Larger stone is used at the bottom, creating more void space, which translates to more water storage. As we build up the base, the stone size gets smaller. All base stone is an open-graded, clean stone which allows water to flow freely through it.  

Reinforcement

In a permeable system, we do not use geotextile between your base material and the soil. We want water to flow to the bottom of the base, then seep into the soil and groundwater. After all permeability is the entire point, right? A geotextile can slow and/or stop seepage into the ground, so we leave it out.  

Further Reinforcement

A geogrid product can be installed within the stone base layer to provide extreme strength and increase load capacity. This can also help prevent rutting from cars traveling the same path again and again. Drive Grid, a Unilock product, was designed specifically for this purpose. 

Edging

We install a paver edge restraint around the perimeter of the pavers. This stops pavers from shifting and spreading apart over time.

Joint Material

We do not use polymeric joint sand in a permeable system. Instead, we install a fine chip stone between the the pavers. This is a clear stone that allows water to flow through the joints and into the storage area below.