How Toselect A Roof Drain

It is an essential element to ensure water drains properly off of your roof.

How toselect a roof drain.

First and foremost be sure to comply with all local plumbing codes. The roof structure may sag due to the added weight of ponding water. The zurn roof drains and drain accessories represent more than 100 years of experience in supplying engineered roof drainage equipment to the construction market. The new drain must fit flush on the roof surface inside the old drain bowl and the new outlet pipe must fit inside the old outlet pipe.

Type of roof construction roof pitch maximum volume of expected rainfall and storm design criteria this information must be obtained from your local weather bureau and or local code authority desired rate of drainage. Determine 100 year 1 hour rainfall rate used for location of building select number of roof drains and calculate the roof area sloped to each drain size horizontal storm drainage piping size vertical storm drainage piping. Buried or underground roof drainage downspout defects clogging overflowing holes corrosion leaks that cause wet basements or crawl areas proper installation of buried downspout extensions proper installation of french drains seepage pits at flat sites gutter downspout defects cause wet basements crawl areas questions answers about installing maintaining repairing buried roof. When the through building roof drain system has become clogged even if it does not burst and lead to building flooding it causes other building problems.

When selecting a roof drain note. Take the roof s total square footage and divide by the total square footage handled by one drain. The above sizing data is offered as a guide only. Roofing materials are designed specifically to be compatible with the pitch of the roof.

Calculate drains needed. Clogged roof drains ponding water sagging roofs. Floor drains or area drains when used to drain exterior areas should have an open area equal to twice the transverse area of the connecting pipe table 1 see roof drain section for rainfall and sizing data table 1 recommended grate free areas for various outlet pipe sizes. The pitch of your roof also helps determine the type of materials that can be used on your roofing system.

The result is the number of drains needed. To select the proper roof drain the following information must be known. The best type for the application depends on several factors such as the size and slope of the roof the desired appearance and how much regular maintenance the drain system might need. To select the proper roof drain the following information must be deter mined by the designer specifier.

Roof drains for flat or low slope roofs come in a few standard types. The primary reason roof pitch exists in the first place is to redirect water. This table is based on zurn s roof drain vertical requirement for horizontal roof areas at various rainfall rates table. In that case you would use one of our smaller bowl drains.

The old bowl may be a little or a lot too shallow for this.