Roof Drains


There are a number of distinct varieties of roof drains and roof drain cover in Mobile, AL and each is an unique answer to the variety of roof styles and their drainage issues. You need to think about the type of roof, its dimensions, and the roof pitch to be able to select the correct drain. You also may want to think about the site of the drain, what amount of rainwater is expected and safe practices when choosing a roof drain for a residence or business structure.

Gambrel, dormers, hip and gable roofs shed water thanks to gravity. Flat roofs, on the other hand, accumulate water. Until the water is guided out and away from the roof structure, it will create pools that could inevitably leak and the accumulated weight may eventually result in structural damage. That is the reason that roofs with a pitch of less than 2% should have roof drains located in the lowest places on the roof in which water pools and should be evenly spread all throughout the roof top.

Roof Drain Kinds


There are several different alternatives of roof drains. They generally fall into 2 groups: flat roof drains and pitched roof drains. Pitched roof rainwater drains normally consist of gutters that accumulate rainwater which travels via gravity to the roof edge. Gutters channel this water in the direction of downspouts which direct the water flow down and away from the structure or in to sewer lines. Flat roof drains can be one of three main types: scuppers, inner drains or siphonic drains.

Roof Rainwater Drain Scuppes


Scuppers are located on a roof's periphery. Scuppers can also be placed on a balcony or terrace. Small openings are cut in the side of the roof structure so water can empty and drain the roof top. Scuppers can attach to a downspout, or could be extended to make sure that water is guided away from the structure sides and foundation.

Inner Roof Drains


There are many kinds of inner drains for flat roofs. They are positioned at low spots on the roof and connect to interior drainage pipes that route water outside or in to a sewer system. Many styles of internal roof drains have domes, strainers or covers which prevent debris from clogging the roof drain pipe. These types of drains operate via gravitational force funneling standing water thru the roof drain system. They can be made of PVC, cast iron or cast aluminum.

Siphonic Roof Drains

Siphonic roof drains are a more efficient substitute for gravity drainage. Traditional flat roof drainage allows both air and water to go into the drain system creating pipe space occupied by both air and water. By incorporating an engineered baffle to the sump of the drain system it produces a siphonic drain that removes air from the system and allows for smaller sized pipe diameters to be used. When all of the air is removed, a negative air pressure in the tail portion of the drain is set up which draws water off the roof siphonically. Although used primarily for flat roofs, siphonic drains can also be set up on angled roofs.

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