How many feet of gutter per downspout

It is decided to drain the building with 4 downspouts located at each corner of the building. An expansion joint will be installed in each gutter between the downspouts. The plan area of this building is sq ft. Since the slope is 6 in. Thus each of the four downspouts will serve a sq ft. Opposite Boston, it is found that 1 sq in. Divide by 16 to determine that each downspout should have a minimum area of It is found that there is a choice of; a 5 in. Spacing and size of outlet openings.

The gutter can never be any more effective than the outlet and downspout selected to drain it. Downspout sizes must not exceed the bottom width of the rain gutters. Slope of the roof. The gutter must be of such a design and location that water from a steep pitched roof will not by its own velocity tend to overrun the front edge. Style of gutters to be used. All gutters are not effective for their full depth and width. Maximum length of gutter. Rain Gutter support capability.

Supports should be based on full capacity of the gutter. Ice load capacity also affect the size and strength of the system. Sloped gutters may be. They come in a variety of shapes tubes, chains, etc. If we have to sum it up in a single rule, gutters need a downspout around every 30 to 40 feet. For most homes, this means installing spouts at either end of a gutter section. But wait! There are many more important factors that can change this broad rule. They include:.

Measuring the square feet of the roof , along with knowledge of local rainstorms, is invaluable when making decisions like these. Ultimately, changes to either your downspout or your gutters could help solve overflowing problems. A final and important consideration. Downspouts tend to be around 2 to 3 inches in diameter, allow for various shapes. But they can come in far larger sizes. However, the gutter needs to be large enough to accommodate the spout, so measuring is still important!

Photo source: Flickr. Im sure some math wiz could figure out the exact per foot with the water. Hey its just a rule of thumb. Not to get all upset over tho.

Thanks for that link. So, 2x3 downspout can drain a 6 square roof… very interesting. Now I know. Yes, there is a method for calculating the size and quantity of downspouts needed to drain your roof properly. First, I would need to know the square footage of the roof area s being drained, and that includes any other roofs that drain onto the roof area where the gutters are mounted. Next, I would need to know the closest large city, so I can look into the year rain storm totals.

I also need to know what size gutters are installed on the building, and then I could give you a square inch total of downspouts needed. To make it easier, I also would like to know if you are using round or rectangular downspouts, and what the current size of those downspouts are.

Hi, Do your downspouts take away the water now? If they do then you do not need anymore. You can just install a larger downspout. That will remove more water. Hi, Gutter guards are very helpful. If you have pine needles you will still have to clean them. Not as often.