Enter the total roof area and the square feet per drain into the Calculator. The calculator will evaluate the Number of Roof Drains. 

Number of Roof Drains Formula

RD = RA / SFD

Variables:

  • RD is the Number of Roof Drains (drains)
  • RA (ft^2) is the total roof area
  • SFD (ft^2/drain) is the square feet per drain

To calculate the Number of Roof Drains, divide the total roof area by the square footage per drain.

How to Calculate the Number of Roof Drains?

The following steps outline how to calculate the Number of Roof Drains.

  1. First, determine the total roof area. 
  2. Next, determine the square feet per drain. 
  3. Next, gather the formula from above = RD = RA / SFD.
  4. Finally, calculate the Number of Roof Drains.
  5. After inserting the variables and calculating the result, check your answer with the calculator above.

Example Problem : 

Use the following variables as an example problem to test your knowledge.

total roof area = 5000

square feet per drain = 1000