Maintaining Your Gutter System

Water from the roof reaches the ground through gutters and downspouts or by flowing directly off roof edges. Because downspouts create concentrated sources of water in the landscape, where they discharge is important. Downspouts should not discharge where water will flow directly on or over a walk, driveway or stairs. The downspouts on a hillside building should discharge on the downhill side of the building. The force of water leaving a downspout is sometimes great enough to damage the adjacent ground, so some protection at grade such as a
splash block or a paved drainage chute is needed.   Water that flows directly off a roof lacking gutters and downspouts can cause damage below. Accordingly, some provision in the landscaping may be needed, such as a gravel bed or paved drainage way.

The rule of thumb for downspouts: at least one downspout for each 40 feet (12 m) of gutter. For roofs with gutters, make sure that downspouts discharge so water will drain away from the foundation. Downspouts can be checked for size. Seven square inches is generally the minimum except for small roofs or canopies. There should be attachments or straps at the top, at the bottom, and at each intermediate joint. Downspout fasteners can rust, deform, fail or become loose. On buildings with multiple roofs, one roof sometimes drains to another roof. Where that happens, water should not be discharged directly onto roofing material. The best practice is to direct water from higher gutters to discharge into lower gutters through downspout pipes. Wooden gutters are especially susceptible to rot and deterioration and should be monitored. Pitched roofs in older buildings may end at a parapet wall with a built-in gutter integrated with the roof flashing. At this location, drainage is accomplished by a scupper (a metal-lined opening through the parapet wall that discharges into a leader head box that in turn discharges to a downspout). The leader head box should have a strainer. Check the scupper for deterioration and open seams. All metal roof flashings, scuppers, leader head boxes and downspouts should be made of similar metals.

Homeowner maintenance includes cleaning the leaves and debris from the roof’s valleys, gutters and downspouts. Debris in the valleys can cause water to wick under the shingles and cause damage to the interior of the roof. Clogged rain gutters can cause water to flow back under the shingles on the eaves and cause damage, regardless of the roofing material. This condition can occur with composition shingle, wood shake, tile or metal. In the winter if drainage systems are clogged this moisture that has wicked under the roof covering can create a ice dam and cause damage to your roof system.

Inspect the downspouts to make sure they are clean, clogged downspouts will cause the same damage.If downspouts are underground, make sure the area of discharge is cleared of grass  and other plant material.  If the discharge area is blocked water can back up into the downspouts also creating an ice blockage and eventually into the gutters and cause the same ice dam issues as described above.

Ice dams can form on pitched roof overhangs in cold climates subject to prolonged periods of freezing weather, especially those climates with a daily average January temperature of 30º F (-1º C) or colder. Heat loss through the roof and heat from the sun (even in freezing temperatures) can cause snow on a roof to melt. As water runs down the roof onto the overhang, it freezes and forms an ice dam just above the gutter. The ice dam traps water from melting snow and forces it back under the shingles and into the building’s interior.  Watch the edge of the roof overhang for
evidence of ice dams and look at the eaves and soffit for evidence of deterioration and water damage. If the house has an attic, the underside of the roof deck at exterior walls can be checked for signs of water intrusion.

Safety:  Don’t forget about safety when cleaning your gutters.