How do I keep gutters from sagging?

Gutters stay straight when the weight in them stays low and the support under them stays strong. That means cleaning them often enough that leaves and water never build up, keeping downspouts clear, keeping hangers tight and close together, holding the slope toward the downspout, sealing leaky joints before they rot the fascia, and protecting the gutter from ladders and branches. Most of it fits into the cleaning you should already be doing.

Keep the weight down

Clean on a schedule. The Northern Virginia Soil and Water Conservation District says gutters should be cleaned of debris at least once a year, and more often if you have trees close to the house.^[1] Wet leaves and roof grit are heavy, and they dam the water behind them. The district also notes that gutter guards can reduce how often gutters need cleaning,^[1] though a guard does nothing for a hanger that is already loose.

Clean before winter. Ice is the heaviest load a gutter carries. The Building America Solution Center, a U.S. Department of Energy guide, advises homeowners to make sure gutters are clean as winter approaches, or fit screen leaf guards, so they drain and do not fill with water that could freeze.^[2] It also notes that gutters can fill with snow, which may freeze and become part of an ice dam already forming on the roof.^[2] A late-fall clean, after the leaves are down, matters most.

Keep downspouts clear. A gutter only empties as fast as its downspouts. Amerimax rates that a 2-by-3-inch downspout drains 186 gallons per minute and a 3-by-4-inch one drains 434,^[3] and it recommends larger or more downspouts for wide roof areas, heavy downpour areas and gutter systems that overflow.^[3] Flush each one with a hose after cleaning; if it backs up, clear it before the next storm. See how to keep downspouts from clogging for more.

Watch for overflow. The conservation district says streaks or watermarks on the outside of the gutters and downspouts, and erosion along the drip line, are signs the gutters overflow when it rains and need cleaning.^[1] Overflow often means a stretch is holding water, and held water is weight.

Keep the support strong

Hanger spacing. Amerimax's installation sheet calls for one hanger every 24 inches, or every 18 inches in areas with heavy ice and snow loads.^[3] When you clean, measure the spacing on any run that looks wavy, and add hangers where the gaps are wider.

Hanger condition. Wiggle each hanger as you go. Smooth spikes tend to back out over the years, and a loose one is easiest to deal with before the gutter starts to dip. Screw-in hidden hangers set into firm wood usually hold better.

The slope. Gutters should fall toward the downspout, and the Building America guide says they should slope at least 1/16 inch per foot of run toward the downspouts.^[2] A stretch that holds a puddle a day after rain has lost its fall. Fix it early; how to adjust gutters so they drain properly walks through it.

Dry fascia. Hangers are only as strong as the board they are screwed into, and fascia rots where water drips through joints or runs behind the gutter. Reseal leaking joints promptly. Sealant makers are specific about conditions: OSI's directions say surfaces must be clean, dry and free of old caulk, grease, dust and other contaminants,^[4] and its gutter sealant goes on between 40°F and 120°F.^[4] The full method is in how to fix a leaking gutter seam.

Protect gutters from damage

The Building America guide notes that vinyl and aluminum gutters can crack or dent from impacts from ladders and tree branches.^[2] Two habits prevent most of that damage. Lean ladders on the wall, never on the gutter. And keep branches trimmed back from the roof edge so they cannot fall on, rub or drop debris into the run.

Ladder safety for routine checks

Virginia Commonwealth University's ladder program says to pull the base out so its distance from the wall is one-fourth the height to the point of support,^[5] and the top should extend at least 3 feet above the eave, gutter or roofline.^[5] It also rules out ladders on slippery surfaces such as snow, ice or oily deposits,^[5] so winter ice in the gutter is not a ladder job. Before raising the ladder, look up: Virginia's Overhead High Voltage Line Safety Act forbids work that puts a person or a ladder within 10 feet of any overhead high voltage line.^[6]

Stop and call a pro if

• The gutters are above the first storey or can only be reached from the roof.
• The fascia is soft, stained or crumbling where the hangers attach.
• A run has already dropped, kinked or pulled away from the house; why gutters sag explains the causes.
• The gutter overflows even when clean, which may mean it needs larger gutters or more downspouts. In Virginia, a Class C licence covers construction, removal, repair or improvement jobs with a single contract over $1,000 and under $30,000,^[7] so check the licence of anyone quoting that work.

Browse the roofing answers, gutter repair on Loclis or exterior pros around Blacksburg. If your gutters need refastening or new hangers, describe the gutter repair once and licensed local businesses quote it.