How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask Susan Latta Your Own Question
Susan Latta
Susan Latta, General Contractor
Category: Home Improvement
Satisfied Customers: 104
Experience:  Licensed Contractor and Certified Kitchen and Bath Designer
Type Your Home Improvement Question Here...
Susan Latta is online now
A new question is answered every 9 seconds

What is the minimum down spout drain required 3"

Customer Question

Hello,What is the minimum down spout drain required for a 3" gutter?
Submitted: 1 year ago.
Category: Home Improvement
Expert:  Susan Latta replied 1 year ago.

HI my name is ***** ***** I can assist you with your question regarding your downspout size.

Are your 3-inch gutters enough to handle the rains in the area you live? Are they the right size for the pitch and square footage of the roof? plus the amount of rainfall in your area?

The only reason I asked is because 3-inches is not very large, but that could be because I'm used to a lot of rain in this area and you may not have as much rain as what we get here. It all depends on the area you live.

If your gutters are the correct size, than 2" x 3" downspouts should be fine.

If you feel I addressed your concerns, please be so kind as to rate my answer with positive feedback; this is the only way I receive recognition from the site for my assistance. Thank you very much!

By providing a positive rating will not end our conversation, should you need me for any follow-up. Simply click 'Reply' for clarification or additional information, if needed, and I will be happy to continue. There is no additional charge for follow-ups.

Customer: replied 1 year ago.
The downspout is 2" round, should it still be fine? How do you determine the size of the downspout to be used for 2" gutter?
Expert:  Susan Latta replied 1 year ago.

How much rainfall do you receive a year?

What is the square footage of the roof of the house?

I thought you said it was a 3-inch gutter. Is this in the U.S.?

Customer: replied 1 year ago.
The design should be according to the code not guess what the rainfall will be in CA? The 1994 UPC Table D-3, Size of Gutters, does not show a rainfall for less than 2 inches per hour, then the minimum size of the gutter must be used according to the UPC code which states 3" minimum. .
How do you calculate the gable roof areas (CA)? The gutter is a 2-1/2" wide. Thanks.
Expert:  Susan Latta replied 1 year ago.

I apologize but I have never heard of guttering that small and am not relating to your question. I going to opt out of this session and let another expert help you that knows more about guttering across the U.S. than I do. Thank you, Susan