What thickness of topsoil is typically used above the granular base in a concrete gutter?

The appropriate thickness of topsoil that is typically used above the granular base in a concrete gutter is 12 inches. This measurement is designed to provide sufficient soil for vegetation, support drainage, and promote the health of plants that may be located near the gutter area.

Using 12 inches of topsoil allows for adequate moisture retention and root growth for any landscaping that may be placed in proximity to the concrete gutter. A thicker layer could potentially lead to excessive saturation and complicate drainage around the gutter system, whereas a thinner layer might not support the necessary vegetation health or soil stability. Overall, 12 inches strikes a balance between functional hydrology and the practical needs of landscaping, making it the standard choice in such applications.