downspout

A downspout is a vertical pipe attached to the exterior of a building that channels rainwater from a roof gutter to the ground or a drainage system. Its primary function is to move water away from the building envelope to reduce erosion, foundation damage, and basement flooding.

Design and configuration: Downspouts are typically rectangular or round and connected to gutters via an outlet. They commonly range in size around 2x3 inches or 3x4 inches. Materials include aluminum, vinyl, galvanized or stainless steel, copper, or other metals. They may incorporate elbows, straps, and extensions to direct water away from walls toward drains or splash blocks.

Zones and placement: Downspouts are installed at roof corners or eaves and positioned to optimize drainage. Extensions or splash blocks prevent water from pooling near the foundation. In colder climates, outlets must be protected to reduce ice damming and blockages.

Maintenance and problems: Debris such as leaves can clog downspouts, causing backups and overflows. Common issues include loose fasteners, leaks at joints, corrosion, or damaged sections. Regular cleaning and inspection mitigate problems.

Standards and practices: Local building codes may require downspout sizing, placement away from openings, and extension length. Some systems use rain barrels or cisterns to harvest water.

See also: rain gutter, rainwater harvesting, splash block.