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Commercial retaining walls require proper drainage to reduce hydrostatic pressure. Native soil is comprised of multiple layers that determine the ability of the water to move through the soil. Low permeability soil layers can trap water against below grade structures. The force of water can compromise the wall, creating leaks and in extreme cases, structural failure. Stone drains require extensive excavation and are not always practical or feasible.
Failure to design for proper drainage can result in increased material cost to handle increased load requirements or may require expensive repairs.