Does a flat roof need a drain?

Unlike other roofing types that are slanted or sloped to allow water to drain automatically, flat roofs need a built-in drainage system to help remove moisture and debris. Poor drainage can lead to serious issues with flat roofing, from leaks to structural damage.

What is a flat roof drain called?

Gutters. Gutters are the most commonly used drainage system when it comes to flat roofs. Just like the gutters installed on sloped roofs, these marvels catch rainwater and divert it into a downspout, which carries it away from the foundation.

How do you slope a flat roof for drainage?

For drainage purposes, the current building codes require a minimum two percent slope or a one-fourth unit vertical for every 12 units horizontal. In other words, the roof must slope one-fourth of an inch for every 12 inches.

How much does it cost to install a roof drain?

Installing drainage runs most homeowners between $1,959 and $6,000 with an average cost of $3,965. Small, simpler solutions could be as low as $500 and more complicated projects could get as expensive as $18,000.

What is a roof sump?

Description: Copper roof sumps are generally used for draining small roof areas such as canopies. Their size depends on the roof area, the numbers of roof sumps used on the roof, the drainage outlet size, and the location of the sump on the roof.

What is a roof drain sump receiver?

Roof Sump Receiver Distributes weight of the drain and securely cradles drain in roof deck. (It is recommended for most Z100, Z121, and Z125 installations.)

How many drains does a flat roof need?

It is important to remember that no roof area should ever have less than two roof drains. Size and placement of rooftop equipment may necessitate additional roof drains. Consideration should also be given to local codes whish may require separate overflow drain systems.

Where do flat roof drains go?

The drains are usually placed near the center of the building. They attach to pipes that drain the water down through the building’s roof. This keeps the water safely away from the walls and foundation.

What is the minimum slope required for proper drainage of flat roofs?

For drainage purposes, the current building codes require a minimum two percent slope or a one-fourth unit vertical for every 12 units horizontal. In other words, the roof must slope one-fourth of an inch for every 12 inches. The slope is barely noticeable to the naked eye.

What should a flat roof slope be?

The short, simple answer is 2:12 has traditionally been considered the absolute minimum acceptable roof slope suitable for asphalt shingles.

Why do you need a drain sump pan on a flat roof?

Roof drain sump pans prevent the huge pools of standing rainwater that are caused by roof drains that are sitting too high on the flat roof. This is a common occurance on flat roofs.

How big of space do I need for sump pans?

If you have a residential or light commercial roof drain installation project and they are 16″ on center, use model SSP or SCP sump pans. You will need 14″ of clear space between them. If you have a large commercial or industrial roof drain installation project and your roof joists are 24″ on center or more use model LSP or LCP.

How big of a drain do I need for my roof?

Measure the vertical distance between the roof (bottom side) and the ceiling if there is one. If you have at least 13″, use a bottom outlet roof drain. If you have minimal space such as 8″ to 10″, use a side outlet roof drain. This will get you pointed in the right direction.

Why is the drain on my roof discolored?

BEFORE..2 the discoloration and staining of the roof around the roof drain is caused by the standing rainwater. This would eventually cause the roof covering to fail.