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.
- First, determine the total roof area.
- Next, determine the square feet per drain.
- Next, gather the formula from above = RD = RA / SFD.
- Finally, calculate the Number of Roof Drains.
- 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
Frequently Asked Questions
How do I measure the total roof area accurately?
To measure the total roof area, you can use a tape measure to measure the length and width of your roof and multiply these dimensions together. For more complex roof shapes, you might need to divide the roof into manageable sections, calculate the area of each section, and then add them together for the total area.
Why is it important to calculate the number of roof drains needed?
Calculating the correct number of roof drains is crucial to prevent water accumulation and potential damage. Too few drains can lead to water pooling on the roof, increasing the risk of leaks, structural damage, or even collapse under heavy rain conditions.
Can the square feet per drain vary depending on the roof type?
Yes, the square feet per drain can vary depending on the roof type and the local climate conditions. Flat roofs or roofs in areas with heavy rainfall might require more drainage capacity compared to sloped roofs or roofs in drier climates.
What should I do if my calculated number of roof drains doesn’t match the existing setup?
If your calculation does not match the existing setup, it’s advisable to consult with a professional roofer or a structural engineer. They can assess your roof’s specific needs and recommend whether additional drains are necessary or if adjustments to the current drainage system are required.
