Our Small Deck Drain is designed for installation in flat roofs of all construction types used for recreational promenades.. Its 8" Sq. cast iron grate is engineered for light wastewater accumulations and light traffic where the static load is less than 2,000 lbs. (900 kg.). Tamper resistant for safety, the grate is secured to a corrosion resistant Duco coated cast iron drain body and will provide decades of service.