Roof Drains


At this time there are a number of distinct varieties of roof water drains and roof drain downspout in Huntsville, AL and each one is a specific answer to the variety of roof types and their drainage challenges. You should consider the type of roof, its size, and the roof pitch to be able to choose the most suitable drain. You also need to take into consideration the location of the drain, what amount of rainwater is expected and safety when selecting a roof drain for a residence or commercial structure.

Hip roofs, dormers, gable and mansard roofs shed water due to gravity. Flat roofs, alternatively, accumulate rain water. Unless the water is directed out and away from the flat roof structure, it will most likely develop pools of water that could inevitably leak and the amassed weight will eventually cause damage to the structure. That is the reason that roofs with a slope of less than 2% ought to have roof drains positioned in the lowest areas on the roof in which water pools and should be evenly spread throughout the roof surface.

Kinds of Roof Drains


There are several different variations of roof drains. They generally fall into 2 categories: flat roof drains and pitched roof drains. Pitched roof drains usually comprise gutters that collect rainwater that passes by means of gravity to the roof periphery. Gutters channel this water in the direction of downspouts which steer the water flow down and away from the building or into sewer lines. Flat roof drains can be one of three main types: scuppers, inner drains or siphonic drains.

Roof Drain Scuppers


Scuppers are located on a roof's periphery. They can also be installed on a balcony or terrace. Small holes are cut in the side of the roof structure so rain water can flow out and drain the roof top. Scuppers can connect to a downspout, or could be extended to make sure that water is directed away from the building sides and foundation.

Interior Roof Drains


There are quite a few different types of inner drains for flat roofs. These are positioned at low areas on the roof and connect to inner drainage pipes that drive water outside or in to a sewer system. Several designs of internal roof drains have domes, strainers or covers which keep trash from blocking the roof drain pipe. These kinds of drains work via gravitational force funneling standing water through the roof drain system. They are made from PVC, cast iron or cast aluminum.

Siphonic Roof Drains

Siphonic roof drains are a more effective substitute for gravity drainage. Standard flat roof drainage permits 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 that eliminates air from the system and allows for smaller sized pipe diameters . When all of the air is removed, a negative air pressure in the tail portion of the drain is established which pulls rainwater off the roof siphonically. Although used mainly for flat roofs, siphonic drains can also be installed on angled roofs.

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