A round downspout should be one inch larger in diameter than an appropriately sized rectangular downspout. Depending on the shape of the opening in the type K channel, you may need a square-to-round downspout adapter. Round downspouts are traditional and are the most popular downspout shape for domestic and industrial buildings. The round downspouts are designed for easy draining and expulsion.
Rectangular downspouts are usually better suited to the style of houses and can be scaled to different lengths and widths depending on the owner's needs.
