Roof Drains


At this time there are a number of distinct kinds of roof drains and roof drain pipe in Helena, AL and each is an unique answer to the wide range of roof styles and their drainage issues. You need to consider the type of roof, its size, and its roof pitch to be able to select the correct drain. You also need to take into account the site of the drain, how much rainwater is anticipated and safe practices when choosing a roof water drain for a residence or commercial building.

Gable, dormer, mansard and hip roofs shed rainwater water due to gravitational force. Flat roofs, on the other hand, accumulate water. Unless the water is guided out and away from the roof structure, it will most likely develop pools of water that could eventually leak and the accumulated weight may eventually result in compromising the integrity of the structure. 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 where water pools and should be uniformly spaced throughout the roof top.

Types of Roof Drains


There are several different alternatives of roof drains. They basically fall into 2 categories: pitched roof drains and flat roof drains. Pitched roof drains normally comprise gutters that collect rainwater which travels by means of gravity down to the roof edge. Gutters channel this water in the direction of downspouts which direct the water flow down and far away from the building or into sewers. Flat roof drains are one of three primary types: scuppers, inner drains or siphonic drains.

Roof Rainwater Drain Scuppes


Scuppers are situated on a roof's periphery. Scuppers can also be put in on a balcony or terrace. Small holes are cut in the side of the roof structure so that water can flow out and drain the roof surface. Scuppers can hook up to a downspout, or can be lengthened to make sure that water is directed away from the building sides and foundation.

Inner Roof Drains


There are many kinds of inner drains for flat roofs. These are positioned at low places in the roof and connect to interior drainage pipes that direct water outside or into a sewer system. Many designs of internal roof drains have domes, strainers or covers that prevent trash from obstructing the roof drain pipe. These types of drains work via gravitational force funneling pooling water thru the roof drain system. They can be made from PVC, cast iron or cast aluminum.

Siphonic Roof Drains

Siphonic roof drains are a more efficient alternative to gravity drainage. Conventional flat roof drainage permits 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 pipe diameters to be used. When all of the air is eliminated, a negative air pressure in the tail portion of the drain is established which pulls water off the roof siphonically. Though 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 pipe in and around Helena, Alabama, give us a call. We'd be glad to help.