When the city of Grand Rapids, Michigan decided to replace 250 old and damaged tree grates it opted to install porous paving (Porous Pave XL) around its municipal trees. T he city saw it as a cost effective solution upfront, and lowering maintenance costs in the long run.

"The material we selected offered a key advantage for making the installations easier, quicker and less costly," noted Karie Enriquez, PE, assistant project manager in Grand Rapids' engineering department. "We could install [the porous paving] without first removing the grates' metal frames that were affixed to the sidewalks on the edges of the tree openings. Prying out the frames would have damaged the sidewalks and necessitated costly repairs," she explained.

The engineer noted the porous pave bonded to the metal, and the porosity of the new surfacing helps capture storm water runoff. The porous paving is also ADA compliant and eliminated the tripping hazards that existed because of damage to some of the grates.