What makes dome strainers essential for rooftop maintenance?
Many of the buildings in Washington DC with commercial style flat roofs do not have internal drains. Instead, they have rear terminations which feed into guttering and downspout systems.
However, flat roofs that are larger or wider than a typical city rowhome layout may use an internal drain as an alternative to a guttering system.
A dome strainer, also known as a basket strainer, is a filtering type of permanently installed shroud which covers the drain but is elevated above the plane of the roof. In the case of the image below, you can see that the dome strainer is significantly higher than the drain orifice in the roof membrane. That difference in height could allow for some back up in water diversion caused by leaves or tree debris to build-up and water would still flow over and through at the dome strainer. This element is an important part of the design to prevent backups or blockages at the drain at typical rainfalls. It’s very important to maintain internal roof drains because tree debris are constantly falling onto roof systems and need to be cleaned out around drain systems consistently.