At this time there are a few distinct varieties of roof drains and roof drain strainer in Huntsville, AL and each is a specific answer to the variety of roof types and their drainage issues. You should take into consideration the kind of roof, its size, and the roof pitch to be able to choose the right drain. You also may want to take into account the location of the drain, what amount of rainwater is anticipated and safe practices when choosing a roof water drain for a house or commercial structure. Gable, dormer, mansard and hip roofs shed water because of gravitational force. Flat roofs, conversely, collect rain water. Unless this water is routed out and away from the roof structure, it will most likely create pools that could inevitably leak and the amassed weight may eventually cause structural damage. That is the reason that roofs with a pitch of below two percent should have roof drains located at the lowest places on the roof in which water puddles and should be uniformly spaced throughout the roof surface.
Kinds of Roof Drains
There are a number of different alternatives of roof drains. They generally fall into two categories: flat roof drains and pitched roof drains. Pitched roof drains usually comprise gutters which accumulate rainwater that passes by means of gravity down to the roof edge. Gutters direct this water towards downspouts which route the water flow down and away from the structure or into sewer lines. Flat roof drains are one of three primary types: scuppers, inner drains or siphonic drains.
Roof Drain Scuppers
Scuppers are located on the roof's perimeter. Scuppers can also be placed on a balcony or terrace. Small openings are cut in the side of the roof structure so rain water can flow out and drain the roof top. Scuppers can hook up to a downspout, or can be extended so that water is guided away from the structure sides and foundation.
Interior Roof Drains
There are many kinds of inner drains for flat roofs. These are installed at low spots on the roof and connect to interior drainage pipes that route water outside or into a sewer system. Many styles of internal roof drains have domes, strainers or covers that keep debris from blocking the roof drain pipe. These kinds of drains work via gravity funneling standing water through the roof drain system. They can be made from PVC, cast iron or cast aluminum.
Siphonic Roof DrainsSiphonic roof drains are a more efficient alternative to gravity drainage. Standard flat roof drainage allows both air and water to enter the drain system producing pipe space which is occupied by both air and water. By adding an engineered baffle to the sump of the drain body it creates a siphonic drain which eliminates air from the system and permits smaller sized pipe diameters . When all of the air is removed, a negative air pressure in the tail piece of the drain is set up which attracts water off the roof siphonically. Though used mainly for flat roofs, siphonic drains can also be installed on pitched roofs.
If you need more information about flat roof drain or roof drain strainer in and around Huntsville, Alabama, give us a call. We'd be glad to help.