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Sidewalk cutout details
Coarse gravel (at least two-inch particle size) used as a sidewalk base helps keep roots well below the walk.
Another method places stone pavers over a structural soil mix or, less preferably, over loose soil connecting cutouts; the sidewalk can also be cantilevered over loose soil. Pavers tend to heave from freezing and thawing of the soil, especially in clay soil.
Another alternative to conventional design is to provide a long strip of loose soil connecting a row of cutouts (see below). This creates a corridor of soil suitable for root penetration. These techniques allow pedestrians to walk freely over the area and provides air and water to the root system.
