Why Choose Us?


At Root Cause, we install a flexible, rubberized, porous paving system known as Porous Pave XL. This practice offers a superior solution to allow people and trees to live cohesively together in a wide variety of commercial, residential and public works applications. We install this type of paving in tree pits (i.e. the opening in the sidewalk for the area around the tree). The next time you are walking in downtown Seattle, look down and you will see firsthand the quality as well as the workmanship of Root Cause. This best practice is also used for walking paths in the vicinity of tree roots, parking paths and driveways.


Key Differentiator:


This technique offers superior permeability, outstanding adaptability yet displays durability. Porous or permeable pavement helps with water drainage by allowing the water to percolate through the pavement into the soil below. With concrete or asphalt, the water must run off the sides into streams and the local water table.


The Process:


The material is a combination of rubber, rock and glue mixed together and contains 25% pore space to allow water to pass through and reach the roots of the trees. Flexible porous paving is made from kiln-dried rock, glue and recycled tires which helps us preserve existing trees while expanding the walking surface around them. Think more space for “green bikes” Seattleites love and think fewer tripping hazards for the elderly and the fashionistas in their high heels.


From rootcauseseattle.com: Flexible porous paving is designed to hold up to the demands of modern infrastructure while remaining porous and flexible. It is a cost-effective solution for maintaining healthy trees in an urban environment.