Eavestrough sagging or pulling away: causes and fixes

What holds your eavestrough up in the first place?

Two things: the hangers, and the board they are fastened to. Every run of eavestrough hangs from fasteners along its length, and every one of those fasteners goes into the fascia, the board along the edge of your roof. When a run sags or pulls away, one of those two has let go.

That sounds obvious, but it is the whole diagnosis. A hanger that has failed on a sound board is a small job. A hanger that has let go because the wood behind it is soft is a different job entirely, and treating the second like the first is the most common reason a sag comes back.

How a run is hung depends on its age and who put it up. Older eavestrough is often held with long spikes driven through the front of the trough, through a sleeve, and into the board. Newer installs usually use hangers that sit inside the trough, clip under its front lip and screw into the fascia, so you do not see them from the ground. Either kind can fail, and they fail in different ways.

What makes eavestrough sag or pull away?

A sag comes down to one of four causes. More than one can be at work on the same run, and the last one on this list is the one that matters most.

Hangers that fail, or too few of them. A hanger can bend, crack or snap, especially after a heavy winter. A run can also be hung with too few hangers in the first place, so each one carries more weight than it should and the trough dips between them.

Spikes backing out. Spikes hold by friction in the wood. As the board swells and shrinks with the seasons, and as the weight in the trough pulls forward on them every time it rains or freezes, they work their way loose. You see the head of the spike standing proud of the trough, and a gap opening between the back of the eavestrough and the house.

Weight: water, debris and ice. Eavestrough is built to carry water moving through it, not water sitting in it. A run that has lost its slope holds water at the low point, and that weight pulls the low point lower. Leaves and roof grit packed into the trough add to it, and in a London winter the water in a sag freezes, ice builds on top of it, and the load on every hanger near that spot goes up again.

Rotted fascia behind it. This is the cause that decides the fix. A fastener only holds as well as the wood it is driven into. When water has been getting behind the eavestrough for years, the fascia goes soft, and a screw or spike in soft wood pulls out under load no matter how good the hanger is. Our guide on how to tell if your fascia or soffit is rotting covers the signs in detail.

These causes feed each other. A failed hanger lets the run dip, the dip holds water, the water gets behind the trough and soaks the board, and the soft board lets go of the next hanger along.

How can you tell which one you have from the ground?

You can narrow it down a lot without a ladder. Walk around the house on a dry day, then again in a steady rain, and look for these.

A single dip in an otherwise straight line. Stand at a corner of the house and sight along the eavestrough. One low point between two hangers usually means one hanger has failed or a spike has backed out at that spot.

A gap between the eavestrough and the house. If you can see daylight or the board behind the trough, the fasteners at that spot are pulling out. Look closely at the face of the trough: spike heads sticking out are a clear sign.

A run that dips in several places, or droops along its whole length. That points to too few hangers, or to the board behind the run going soft in more than one place.

Staining, peeling paint or dark patches on the fascia, especially in a band just under the eavestrough, or on the window sills and siding below a sag. Those mean water has been getting behind the trough, and the board is suspect.

Water spilling over the front in the same spot every rain, or standing water in the trough a day after it stops. That is a run that has lost its slope, whatever caused it. If overflow is your main symptom, our guide on why eavestrough overflows walks through the other causes.

Icicles that form along the same stretch every winter. Ice builds where water sits in a sag or spills over the front, so a row of icicles in one spot often marks the low point before you can see it in summer.

If you can safely reach the board on a ladder, press a screwdriver into the fascia near the sag. Sound wood resists. Soft wood gives, crumbles or feels spongy. If the eavestrough is on a second storey, skip this and have someone look for you.

What is the fix for each cause?

The fix follows the cause, and the board behind the run sets which one you need.

A failed hanger or loose spikes, on sound board: rehang the run. We refasten the eavestrough with new hangers where the old ones have failed or backed out, and set the slope so the water drains to the downspout again. It is a straightforward eavestrough repair on a sound board. A run that drains properly is not holding water, so it is not loading the hangers or feeding ice in winter.

Too few hangers along a sound run: add hangers and reset the slope. The same job, done along the whole length rather than at one spot.

Rotted fascia behind the run: replace the board first. The eavestrough is fastened to the fascia, so it has to come down before the board can be replaced. The rotted section is cut out, new board goes in, and the eavestrough is hung on sound wood. We cover the new board with a clean, finished wrap that matches your eavestrough. That is soffit and fascia work, and it is the only fix that holds when the board has gone.

A run that is failing in several ways at once: replace it. If the eavestrough sags in several places, leaks at the seams and sits on soft board along long stretches, rehanging only buys a season. Since it is coming down for the board anyway, that is the right time to decide whether it goes back up or is replaced. Our guide on whether to repair or replace your eavestrough covers how to make that call.

Why does rehanging onto rotted fascia fail?

Because the hanger is not the weak point. The wood is. Rotted fascia cannot hold a fastener, so new hangers screwed into soft board pull out under the same load that pulled the old ones out. You pay for the repair, the run looks straight for a while, and after a winter or two it is sagging in the same spot.

It also keeps the cause in place. Water that got behind the eavestrough rotted that board, and a run rehung on it still sits against wet wood. The rot keeps spreading along the edge, and the next sag shows up a little further along.

Patching around it does not help either. Longer screws, a block nailed behind the hanger or a metal wrap over the rot all leave soft wood behind the fastener. A wrap is worse than nothing, because it hides the rot while it gets worse.

Sometimes you only see the full picture once the eavestrough is down. Old roof edges get modified over the years, and a board that looked fine from the ground can be soft behind the trough. When that happens on our jobs, we show you what we found before anything changes, and we quote the fix rather than rehanging and hoping.

Is a sagging eavestrough urgent?

Usually not an emergency, and we will not tell you it is one. But it does not fix itself, and it gets worse in a loop: the sag holds water, the water gets behind the trough, the board softens, and the next hanger lets go.

The cost of waiting is what the water reaches. Water spilling from a sag runs down the wall onto window sills and into the ground beside your foundation. In winter it feeds ice along the edge, and if your roof also builds ice dams, our guide on ice dams and eavestrough explains how the two problems work together. A sag caught while the board is still sound is a rehang. The same sag left until the board rots needs the board replaced too.

One thing to rule out before you spend anything: a gutter guard will not fix a sag. A guard sits on top of the trough and does nothing for a failed hanger, a lost slope or a rotting board, and it adds a layer that has to come off before the run can be fixed. Our guide on whether leaf guards are worth it explains why.

Common questions

Can I fix a sagging eavestrough myself?

We cannot say without seeing it, because the board decides the fix and you often cannot judge the board from the ground. A run refastened to soft wood sags again however well it is done. Working at the roof edge from a ladder is also where people get hurt, so on a second storey, or wherever you are unsure of the board, have someone look first.

Do you have to take my eavestrough down to fix a sag?

Not always. A run on sound board can often be refastened in place. If the fascia behind it has rotted, yes, because the board cannot be replaced with the eavestrough still fastened to it.

Is the repair covered by your warranty?

Our 10-year workmanship warranty covers new installs and replacements, including new fascia and eavestrough we put up. A repair to eavestrough someone else installed is not covered. We go through the details when we quote.

How long does the work take?

Eavestrough work is usually done in a day. When the fascia or soffit needs replacing too, the job can take a few days to a week, depending on material lead times, and we tell you that when we quote.

Is the inspection free?

Yes. We look at the run and the board behind it, tell you which cause you have and what fixes it, and quote it. We serve London, Ingersoll, St. Thomas, Strathroy-Caradoc, Stratford and Aylmer. Call or text (548) 488-3206, or ask for a free inspection.