Roof Drains


There are a number of different varieties of roof drains and roof drain pan in Anniston, AL and each one is an unique approach to the wide range of roof types and their drainage challenges. You must consider the type of roof, its size, and its roof pitch to be able to select the right drain. You also may want to think about the location of the drain, what amount of rainwater is expected and safety when selecting a roof drain for a home or commercial structure.

Gable, dormer, mansard and hip roofs shed water thanks to gravitational force. Flat roofs, alternatively, accumulate water. Until the water is routed out and away from the flat roof , it will develop pools that may inevitably leak and the amassed weight will subsequently cause structural damage. That is why roofs with a pitch of less than 2% should have roof drains situated in the lowest places on the roof in which water pools and need to be uniformly spread all throughout the roof surface.

Types of Roof Drains


There are a number of distinct variations of roof drains. They basically fall into 2 groups: pitched roof drains and flat roof drains. Pitched roof drains usually comprise gutters that collect rainwater which passes via gravity down to the roof periphery. Gutters transport this water in the direction of downspouts which steer the water flow down and far away from the structure or into sewer lines. Flat roof drains can be one of three main types: scuppers, inner drains or siphonic drains.

Roof Rainwater Drain Scuppes


Scuppers are situated on a roof's perimeter. They can also be put in on a balcony or terrace. Small openings are cut in the side of the roof structure so that rain water can flow out and drain the roof top. Scuppers can attach to a downspout, or could be lengthened so that water is guided away from the building sides and foundation.

Interior Roof Drains


There are many types of inner drains for flat roofs. They are installed at low spots on the roof and connect to interior drainage pipes that drive water outdoors or in to a sewer system. Many models of internal roof drains have domes, strainers or covers that prevent trash from obstructing the roof drain pipe. These types of drains operate via gravitational force channeling pooling water through the roof drain system. They are made of PVC, cast iron or cast aluminum.

Siphonic Roof Drains

Siphonic roof drains are a more effective substitute for gravity drainage. Traditional flat roof drainage allows both air and water to enter the drain system creating pipe space which is occupied by both air and water. By adding an engineered baffle to the sump of the drain system it creates a siphonic drain which eliminates air from the system and permits smaller sized pipe diameters to be used. When all of the air is removed, a negative air pressure in the tail piece of the drain is established which pulls rainwater off the roof siphonically. Though used primarily for flat roofs, siphonic drains can also be installed on angled roofs.

If you need more information about flat roof drain or roof drain pan in and around Anniston, Alabama, give us a call. We'd be glad to help.