Mid- and high-rise buildings have higher user occupancy densities than other sites and therefore require significant parking area. To conserve the site area, these parking areas are typically located underground. Mid- and high-rise buildings most commonly have flat roofs that drain internally to onsite storm sewer networks. These sites typically have common areas, but their size and function vary. | Mid- and high-rise buildings have higher user occupancy densities than other sites and therefore require significant parking area. To conserve the site area, these parking areas are typically located underground. Mid- and high-rise buildings most commonly have flat roofs that drain internally to onsite storm sewer networks. These sites typically have common areas, but their size and function vary. |