Round downspouts are often used with semicircular gutters, but can also be combined with K-style gutters. A 3-inch round downspout can handle approximately 706 square feet of drainage area, while a 4-inch round downspout can handle up to 1,255 square feet. Round downspouts can offer a unique visual appeal and may be preferred for certain architectural styles. The problem with downspouts is not the water capacity in case of torrential rain, but the dirt that accumulates in the downspout.
The larger the downspout, the better the waste will pass through. Large downspouts are harder to clog, expel more water when clogged, and are easier to clean. Its benefits include preventing water damage, increasing gutter efficiency, and extending the life of the gutter system. The gutters extend horizontally along the edge of the roof, while the downspouts carry water vertically from the gutters to the floor.
A crucial aspect, which is often overlooked, is the gutter system and, more specifically, the number of gutter downspouts needed for optimal operation. The water capacity values of a gutter and downspout system are calculated using the height (height) of the water a gutter can hold, the size of the drain outlet (hole) and the number of drains used. You'll use this GPM calculation to select the appropriate gutter and drain size in step 4: Calculate water handling capacity for gutter and drain options. Adding more downspouts is an effective way to increase the capacity of your gutter system without changing the size of the gutters.
