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Gutters and Downspouts

Updated: Apr 4

All gutters need to be kept clean. They should slope uniformly, without sags, to downspouts. Gutter and downspout materials are usually galvanized steel, aluminum, copper, or plastic. Buildings with sloped roofs can have a variety of drainage systems, including Rainwater Harvesting options. With a sufficient overhang, water can drain directly to the ground without being collected at the roof edge, thanks to proper Gutter Slope and Pitch.

Gutters and Downspouts
Gutters and Downspouts

Drainage of low-slope roofs is accomplished in one of three ways: without gutters or downspouts; with gutters and downspouts; or by downspouts that go down through a building’s interior. The illustration below is of a low-sloped roof with interior pipe drainage, showcasing Downspout Placement.

Low-Slope Roof Interior Drainage
Low-Slope Roof Interior Drainage

Drainage without gutters and downspouts can damage the exterior wall with overflow. If the roof has no gutters and downspouts or interior downspouts, the inspector should carefully check the exterior walls for signs of water damage, emphasizing the Importance of Proper Guttering.

Downspouts
Downspouts

Most functional gutters have a minimum ratio of gutter depth to gutter width of 3:4. The front edge is typically ½-inch lower than the back edge, and Seamless Gutters are preferred. Four inches is considered the minimum width except on the roofs of canopies and small porches. If there is a screen or similar device to prevent anything but water from flowing into the gutter, its performance during a rainstorm should be checked to be sure water can actually enter the gutter, and Gutter Guards can help with this.

Gutter
Gutter

Gutters without screens or similar devices should have basket strainers installed at each downspout, ensuring proper Gutter System Maintenance. The inspection image is of a screen covering the gutter, highlighting the need for Gutter Inspection Checklist before cleaning. Cleaning the gutters is a dangerous home maintenance job. Be careful.

Downspouts
Downspouts

Joints at the gutters should be soldered or sealed with mastic to prevent leaks. The steeper the roof slope, the lower the gutter should be placed or positioned, and Gutter Installation Tips should be followed. On roofs with lower slopes, gutters should be placed close to the roof’s surface. Hangers or gutter supports should be placed no more than 3 feet apart, and in climates where ice and snow are long-lasting, hangers should be placed no more than 18 inches apart, ensuring the proper support for DIY Gutter Repairs. The strength of a gutter’s fastening to the roof fascia or building exterior should be strong and secure. Rusted fasteners and missing hangers should be replaced, just like the inspection image below of a detached gutter fastener suggests.

Gutter and Downspouts

The general rule of thumb for downspouts is that there should be at least one downspout for every 40 feet of gutter. For roofs with gutters, make sure that downspouts discharge so that water is diverted and travels away from the foundation. The inspection image shows a downspout that is improperly discharging next to the corner of the house and its foundation.


Permission to reproduce this information is granted by InterNACHI ®

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