Roof Drains


There are several different varieties of roof drains and roof drain pvc in Pelham, AL and each is an unique approach to the wide range of roof types and their drainage challenges. You need to look at the type of roof, its dimensions, and the roof pitch to be able to choose the correct drain. You also need to think about the site of the drain, what amount of rainwater is expected and safety when choosing a roof water drain for a home or business structure.

Gable, dormer, mansard and hip roofs shed water due to gravity. Flat roofs, conversely, collect rain water. Unless this water is guided out and away from the roof , it will most likely develop pools of water that may inevitably leak and the accumulated weight will eventually cause compromising the integrity of the structure. That is why roofs with a pitch of below 2% should have roof drains positioned at the lowest spots on the roof where water pools and need to be evenly spread all throughout the roof top.

Kinds of Roof Drains


There are a number of different alternatives of roof drains. They generally fall into 2 groups: pitched roof drains and flat roof drains. Pitched roof drains normally comprise gutters that collect rainwater that travels by means of gravity to the roof edge. Gutters direct this water in the direction of downspouts which direct the water flow down and far away from the building 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 situated on a roof's perimeter. They can also be put in on a balcony or terrace. Small openings are cut into the side of the roof structure so that water can flow out and drain the roof top. Scuppers can attach to a downspout, or could be lengthened to make sure that water is directed away from the structure sides and foundation.

Interior Roof Drains


There are many kinds of inner drains for flat roofs. They are installed at low places in the roof and attach to interior drainage pipes that route water outdoors or in to a sewer system. Several styles of inner roof drains have domes, strainers or covers that keep debris from clogging the roof drain pipe. These kinds of drains work via gravity channeling standing water through the roof drain system. They can be constructed from PVC, cast iron or cast aluminum.

Siphonic Roof Drains

Siphonic roof drains are a more efficient substitute for gravity drainage. Conventional flat roof drainage allows both air and water to go into the drain system producing pipe space which is occupied by both air and water. By incorporating an engineered baffle to the sump of the drain body it creates a siphonic drain which eliminates air from the system and permits smaller pipe diameters . When all of the air is eliminated, a negative air pressure in the tail portion of the drain is set up which pulls rainwater off the roof siphonically. Although 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 pvc in and around Pelham, Alabama, give us a call. We'd be glad to help.