How to repair failing gutters and downspouts
Four of the most common problems rain gutters incur are leaking, sagging, overflowing, and pooling runoff around the house. If left unattended, any one of these conditions can cause serious water damage to the house and its foundation. Fortunately, the fixes are within the realm of even a modestly skilled do-it-yourselfer.
If your gutters are leaking, the prime suspects are the joints between sections. Standing water in gutters eventually will rust galvanized steel seams or seep through the seams in aluminum gutters.
First check for signs of standing water and sagging. Adjust or add gutter hangers as needed. Allow the insides of the gutters to dry out, brush leaking seams clean, and then apply silicone-rubber caulking compound along the seams on the inside and outside to seal the leaks, as shown at right.
Patch small holes with roofing cement. Use a putty knife to spread the cement generously around the hole. Try to do this on a warm day, but, if the weather is cool, warm the cement to room temperature so it spreads easily.
Repair larger holes in gutters by covering them with patches. Take a sheet-metal patch, embed it in roofing cement, and then apply another coat of cement over the patch, as shown at left.
If your region delivers abundant rainfall, you may want to have your downspout run into a dry well. The well should be a hole 2 to 4 feet wide and 3 feet deep, or a 55-gallon drum—with both ends removed and filled with rocks—that you’ve buried and punctured with holes. Underground drainage pipes should slope to the dry well, which will keep water away from the house’s foundation. Check your local building codes before installing.
Overflowing Rain Gutters
Gutters that overflow can present serious problems to your home’s walls and foundation. If your gutters overflow during a heavy rain, either the gutters and/or downspouts are clogged, the gutters are sagging and thereby preventing water from reaching the downspouts, or the gutters and downspouts are not large enough to handle the volume of rain runoff.
In most cases, gutters overflow because leaves and debris are clogging them, essentially creating dams that prevent water from flowing to the outlets above the downspouts. In fact, these clogs often occur right at the outlets. When this is the case, it’s time to clean out the gutters. (For more about this, see Rain Gutter Cleaning & Maintenance.)
Gutters that sag are a different issue—and the more they fill up with water, the more likely they are to sag because they become so heavy when full. If the gutters overflow but are not sagging or clogged, you will probably need to install new, larger downspouts and gutters.
Sagging Rain Gutters
When full of water, rain gutters can become extremely heavy. As a result, the types made of flexible materials such as aluminum, vinyl, and galvanized steel can begin to bend and sag and their hangers to loosen. As this happens, they cease to do a good job of draining rainwater efficiently, allowing water to pool along their lengths. This, of course, just exacerbates the problem, making them heavier and causing them to sag even more.
To determine if your rain gutters sag, check for signs of standing water or water marks along the inner sides of the gutters. With a level, check the slope—gutters should drop about 1/4 inch for every 10 feet of run toward the downspouts.
To fix them, you may need to replace the hangers or, at the very least, re-seat them. If the gutters are held by spike-and-ferrule hangers, use a hammer to drive the long spike, making sure it goes into solid wood. If it does not grab securely, you may need to replace it with an even longer galvanized nail or, better yet, a long screw.
To tighten clip-style gutter hangers, you will need to lift the roofing material along the eaves and refasten the hangers to the sheathing. Be careful not to crack or create holes in the roofing.
Downspouts may break loose from the gutter outlet or between sections. This often happens when elbows in the sections become clogged with debris.
Take the sections apart and clean out the debris. Then, to refasten them, push the downspout sections and/or elbows together, drill pilot holes if necessary, and fasten them with two 3/8-inch #8 galvanized sheet metal screws. (Don’t use longer screws because debris will hang on them.) Be sure the anchor straps that hold the downspouts to the wall are secure.
Fasten the top downspout to the S-curve outlet with one or two screws at each joint for easy removal for regular cleaning.
Drainpipes on rain gutters are commonly called downspouts. These are the pipes that connect to the gutter that channel water off the roof and send it flowing out onto the ground. There are two major materials that are used for drainpipes: aluminum and PVC. Although one is a plastic and one is a metal, they are both repaired in virtually the same way and the same tools are used for either one.
Replace aluminum drainpipes if they are crushed. Downspout drainpipes come in sections that can be removed and replaced. Drill out aluminum downspouts at the rivet hole, using a drill bit the same size as the rivet. Disassemble the downspout section and replace it with a new piece, using self-tapping sheet metal screws. Screw directly through the aluminum to connect the pieces together.
Replace a PVC drainpipe if it has been shattered. Check to see if your PVC downspout is connected with pressure fittings. Pull the pieces apart by hand. Insert new pieces by pushing them together tightly. Alternatively, cut the PVC pipes if they have been cemented together, using a hacksaw. Cut the PVC above the joint on both sides. Dry-fit a new piece onto the old downspout and sand the ends with 220-grit sandpaper to remove any burrs. Prime the ends with PVC primer, using the brush that comes with it. Brush PVC cement onto the primed ends. Push the PVC ends together for a tight and waterproof seal.
Fill in cracks that are 1/4 inch thick or less with paintable exterior caulk. Apply a small bead over the crack along its entire length. Smooth it down with your finger. Allow it to dry. For white drainpipes, use a white caulk that will blend in automatically; for other colors, use either a color-coordinated caulk or a paintable caulk that you can touch-up with paint to hide the crack.
Stop leaking joints with silicone caulk or rubber spray sealant. Place a bead of silicone caulk directly onto the joint seam where the downspout leaks. Smooth it with your finger. Alternatively, cover the leaking joint with a spray-on rubber sealant.