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Landscape & Design

By Sophie Rhéaume • April 13, 2018

How to Build a Permeable Pavement – Part 1

Techo-Bloc

First part of a demonstration on how to construct a permeable pavement. We cover why the previous job failed, excavation, scarification and adding a geotextile and clean stone.

Forensic analysis

For this project, we pulled all the landscaping out and gave it a more rustic feel with our Valet pavers.

Plus, we introduced an environmental twist by laying these pavers in a permeable pavement application.

We followed the existing grade and kept a similar layout. The water was pitched down to the soil subgrade.

We had to deal with a lot of failures on the previous job.

 failed project

 The root zone from the tree was visible. There was edge failure and significant sinkholes.

This installation was done on stone dust with screenings and quarry waste, and it had all erroded away.

sinkholes2

We demolished the previous job and brought in good clean stone.

demolition

We got the stoop, landing and walkway done in one day. An additional day was required for landscaping.

Here are the steps we followed to construct a permeable pavement.

Excavation and scarification

STEP 1: Excavate down to 9 3/8 inches.

STEP 2: Scarify the subgrade.

We used the tooth bar on the front end of our loader to scarify the surface.

scarify

Our intention was to go down 4 inches.

However, the high clay content of the soil subgrade makes it very cohesive, so we were only able to go down 2 inches.

Scarification opens the surface and allows a greater rate of infiltration.

STEP 3: Add #8 stone.

This filtration medium catches all the fines that may travel through the system before they clog the subgrade. It also helps bearing ability and the rate of infiltration.

STEP 4: Lay a geotextile fabric.

geotex

The fabric should shingle with the flow of water and it should be tensioned with piles of stones.

Never put holes in it.

We used an Alliance geotextile fabric that has an apparent opening size of 70-100 and a weight of 4 ounces. For more information on Alliance’s fabrics, click here.

That’s what you want to use in a permeable pavement under pedestrian traffic.

Find out the next steps in part 2!

VIEW OUR SELECTION OF PERMEABLE PAVEMENT AND BENEFIT FROM CROSS-SECTION EXPLANATIONS TODAY!

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