Seamless vs. Sectional Gutters: Why the Joints Matter

Sectional gutters come in short pieces, often ten feet long, and get joined end to end on the house. They're the kind most hardware and big-box stores sell, because a homeowner can hang them without special equipment.

Each joint is a connector or an overlap sealed against water, usually with gutter sealant and a few screws or rivets. That bead of sealant is the only thing keeping water inside the gutter at that spot, and the overlap leaves a small lip inside the trough where needles and grit can catch. A long eave can have several joints in a single run, and every one is a place where water can find a way out.

A seamless gutter is formed as one piece to the length of the eave, so a straight run has no joints at all, and none of the leak points a sectional run has between its pieces. The only joints left are at the corners, the end caps, and the downspout outlets.

Gutter sealant wears out everywhere, but Colorado is especially hard on it. Strong sun at altitude dries it out and cracks it. Big swings between warm afternoons and freezing nights make the gutter expand and contract, which works each joint a little more with every cycle. Once a gap opens, water gets in, freezes, and pries it wider.

Ice and hail finish the job. A gutter full of ice puts weight and outward pressure on every joint along the run. Front Range hail dents troughs and knocks seams open, and on open lots east of I-25, wind rattles loose sections until the joints work apart.

Plenty of older ranches across the north metro still carry their original sectional gutters, with layer after layer of sealant patches at the joints. Each patch holds for a while, and then the drip comes back.

A dripping seam rarely looks like much from the yard, but it soaks the same spot every time it rains or the snow melts. That spot is usually the fascia board behind the gutter, the soffit next to it, or the siding and brick below.

Over a few seasons the fascia softens and hangers start pulling out, which makes the gutter sag and opens the joints even more. On brick homes, a leaking joint leaves a dark streak or a white mineral stain down the wall. A drip in the middle of a run also lands water next to the foundation, well away from any downspout extension. Watch for these signs:

Seamless gutters start as a coil of flat aluminum. A forming machine in your driveway rolls it into a K-style profile, and each piece is cut to the exact length of the run it's going on. There's no stock length to work around, so a long, straight eave gets one continuous gutter.

Aluminum coil comes in a wide range of standard colors, and Ethan brings samples to the estimate so you can pick one that works with your trim.

The new runs go up on hidden hangers screwed into the fascia, every two feet and closer where snow slides off the roof. Each run is pitched toward its downspout so water drains instead of sitting in the trough and freezing. Standing water is hard on any joint, so good pitch also protects the few joints a seamless system has.

Even a seamless system has a handful of joints, and they need sealing like any other. Each corner is a joint, riveted and sealed where the two runs meet. End caps close off each run and get sealed in place. Downspout outlets fit into a hole cut in the bottom of the trough, then get fastened and sealed.

When a seamless gutter leaks, it's usually at one of those spots, and because there are only a few of them, they're easy to keep an eye on. Look them over during your fall cleanout and again after a hailstorm, and reseal any joint where the sealant has cracked or pulled away.

Downspouts have joints too, between sections and at the elbows. Each piece slides into the one below it, so water falls through the joint instead of running out of it. A downspout assembled upside down will drip at every connection.

If your sectional gutters are dripping at the joints again after another round of sealant, a seamless replacement gets rid of the seams along every straight run. When the old sections come down, Ethan checks the fascia behind each leaking joint, since that's where the wood goes soft first.