Rain Gutter downspouts are a critical part of your homes rainwater protection system. Downspouts that are clogged or improperly installed negate any benefits that your rain gutter system is designed to offer.
The two main styles of residential rain gutter downspouts are square (rectangular) and round. Square spouts are usually installed with a k-style or flat bottom gutter and round downspout with half round gutter.
As far as sizing goes, the industry standard used to be a 2″ x 3″ for square downspouts and 3″ for round downspouts. But today a typical installation would use a 3″ x 4″ sq pipe or 4″ round. There are many benefits to a larger downspout. They let through twice the water, twice the debris and are much tougher to clog.
Gutter downspouts are manufactured in plain (smooth) and corrugated (with ridges.) If you live in an area where you get freezing in the winter its important to use a corrugated downspout to allow for the expansion and contraction of snow and ice.
If you live in an area with allot of snow and ice, heat tape (low voltage wire you can run through your gutter system to keep it free of ice) might be needed to help keep your downspouts from bursting at the seams.