Eliminating overflow; patching. In spring and fall, clear gutters of leaves, twigs, and other debris. Otherwise, water can overflow and seep into the house. Climb a ladder and clear the gutters by hand, wearing gloves. Wherever possible, lean the ladder against the house, not the gutter, and move it often so that you reach no more than 2 feet each side of the ladder.
Use a plumber’s snake to clear the upper part of a clogged downspout. Flush the downspouts and cleaned gutters with a garden hose. Insert stainless-steel or copper leaf strainers in the downspouts to prevent future clogs.
Adjusting gutter pitch
Improper pitch may cause overflow. If water stands in a clean gutter, reset its pitch. First, check that the gutter is touching the overlapping shingles at the high end; adjust if necessary.
Drive a nail into the fascia (the board at the very top of the wall) 1 inch below the bottom of the gutter at each end. Draw a string taut between the two nails. Using a line level, run a level string a few inches below the first.
Measure between the two lines every 4 feet. The distance should increase 1/4 inch for each 4 feet. If it does not, reset the gutter. Starting at the downspout end, disconnect and then reconnect three or four hangers at a time.
Holes in any gutter can be fixed with a fiberglass patching kit. If a metal gutter leaks at a joint, the joint overlap may be wrong-water is running against the seam rather than over it. Take the gutter apart and reconnect it with 1/2-inch No. 6 or No. 7 sheet metal screws. Apply aluminum sealer.