Roof Drains


At this time there are a few different varieties of roof drains and roof drain dome in Helena, AL and each is a specific answer to the variety of roof types and their drainage concerns. You should look at 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, how much rainwater is expected and safety when choosing a roof drain for a house or commercial structure.

Gable, dormer, mansard and hip roofs shed water due to gravity. Flat roofs, alternatively, collect rain water. Unless this water is guided out and away from the roof structure, it will create pools that may eventually leak and the accumulated weight may eventually result in structural damage. That is why roofs with a pitch of less than two percent should have roof drains positioned in the lowest places on the roof in which water pools and need to be uniformly spread throughout the roof surface.

Roof Drain Kinds


There are several distinct alternatives of roof drains. They generally fall into 2 groups: pitched roof drains and flat roof drains. Pitched roof rainwater drains normally consist of gutters which collect rainwater that travels via gravity to the roof edge. Gutters transport this water in the direction of downspouts which steer the water flow down and away from the building or into sewers. Flat roof drains are one of three main types: scuppers, inner drains or siphonic drains.

Roof Rainwater Drain Scuppes


Scuppers are located on a roof's periphery. They can also be placed on a balcony or terrace. Small holes are cut into the side of the roof structure so that water can flow out and drain the roof surface. Scuppers can connect to a downspout, or can be lengthened to make sure that water is guided off of the building sides and foundation.

Inner Roof Drains


There are many types of inner drains for flat roofs. These are installed at low spots in the roof and attach to interior drainage pipes that route water outside or into a sewer system. Several versions of inner roof drains have domes, strainers or covers that prevent debris from clogging the roof drain pipe. These kinds of drains operate via gravity funneling pooling water thru the roof drain system. They are 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 which is occupied by both air and water. By adding an engineered baffle to the sump of the drain system it produces a siphonic drain which removes air from the system and permits smaller sized pipe diameters to be used. When all air is eliminated, a negative air pressure in the tail portion of the drain is established which attracts water off the roof siphonically. Though used primarily for flat roofs, siphonic drains can also be set up on pitched roofs.

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