Roof Drain Pans Co.

Sheet metal roof drain pans uniquely designed to lower or "sump" your cast iron roof drains    

888 900-9145     (949) 297-8689

M - F,    8 am - 5 pm  Pacific Time ​​

​Lowering your roof drain is referred to as "sumping". For effective roof drainage and to eliminate standing rain water on your  flatroof, it is VITAL to have the roof drain lower than the roof surface. This is best accomplished with a drain pan that has been engineered to do exactly that.  Whether you need to "sump" a large or small primary, overflow or combination cast iron roof drain, ​Roof Drain Pans Co  has a roof drain pan that is specifically engineered to lower your cast iron roof drain and eliminate flat roof drainage problems. 

The drain pan is sold with or without the cast iron roof drain.

Shipping throughout North America 



Roof Drain Pans Co has a drain pan for your project.

​​Understand this important point......Your drainage system can be the weakest link in your roofing system. Cutting corners and using the wrong drain pan or cast iron or other roof drain WILL  cause further drainage problems.  

Use model SCP drain pan when you are installing a small, double cast iron roof drain  and the joists are 16" on center

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Use model SSP drain pan when you are installing a single cast iron roof drain and the joists are 16" on center.

Use model LCP drain pan when you are installing a large, double cast iron roof drain  and the joists are 24" on center

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WOOD SUMP BOXES:  Another solution, and by far the most commonly used, is to build a wood drain pan or sump box. This method is cumbersome, time consuming and ultimately expensive when you consider lost production time as a result of building each drain pan on the job site. Fabricating parts and accessories on the job site can be very costly.  The photo shows all of the required materials for a "double sump wood box" drain pan that was demolished on the job. This drainage system will often cause future drainage problems and took several hours to demo. Totally wasted production time!!!

SLOPING THE ROOF:  This involves sloping the entire flat  roof, or a portion of it, toward existing cast iron roof drains (if any exist) using various methods which can be VERY expensive, particularly when sloping the roof involves structural issues. In many cases, installing a new cast iron roof drain is a VERY COST EFFECTIVE solution.  Sloping a roof can however be a valuable part of a drainage system when trying to achieve positive flat roof drainage provided that a correct drain pan is used and new drainage problems are not created. Roof drains are not a substitute for any needed structural repairs. 

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Use model LSP drain pan when you are installing a large, single cast iron roof drain  and the joists are 24" on center

SUMP RECEIVER...Cast iron roof drains currently on the market are sold with a drain pan that is called a "sump receiver" or "bearing pan". The drain pan is often level or higher than the surrounding roof and can cause the roof drains to sit too high, thereby inhibiting the drainage system and creating drainage problems such as large pools of standing rainwater. This is not a solution unless the roof covering is significantly thicker than the sump receiver or drain pan. The objective of a drainage system is "positive drainage" rather than negative drainage !!

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Roof Drain Pans Co.
26060 Acero MISSION VIEJO, CA 92691 US
Phone: (888) 900-9145 Website: