Water running down the wall behind your gutter is not an overflow and it is not a leak in the gutter. It is water that never made it into the gutter at all, slipping into the gap between the gutter and the house. Cleaning the gutter changes nothing, which is usually the first clue. The fix is at the roof edge, and it is usually cheap.
First, make sure that is what you have
Stand under the eave in a steady rain and look at the gutter itself. If it is full and spilling over the front, that is overflow, a different problem. If the gutter is half empty and water is still running down the board behind it, the water is getting behind.
| What you see | What it means |
|---|---|
| Water pouring over the front edge | Overflow. The gutter is full or the water is moving too fast |
| Water running down the fascia behind the gutter, gutter not full | Water behind the gutter. The problem is at the roof edge |
| Drips only at each hanger | Water following the hanger straps back to the board |
| Streaks on the siding below one stretch | A gap where the gutter has pulled away, or a missing piece of drip edge |
| Water behind the gutter only in winter or snowmelt | Coming from higher up, usually an ice dam |
How water gets behind a gutter
Rain leaving a shingle roof is meant to cross a strip of bent metal called the drip edge and fall off its lower lip into the gutter. The 2021 residential code Sioux Falls enforces requires that drip edge on shingle roofs, extending at least a quarter inch below the roof deck. Four things defeat it.
The gutter is in front of the drip edge. This is the most common cause on houses with newer gutters. The back of the gutter should sit behind the drip edge so the metal laps into the trough. When the installer fastens the gutter over the drip edge instead, the water drips off the lip and lands behind the gutter, exactly where it should not. Sighting along the eave from below usually shows it: you can see the drip edge hanging outside the gutter back.
There is no drip edge, or it is too short. Older roofs often have none. Without it, water clings to the underside of the bottom row of shingles, follows it back to the fascia and runs down. Water does not simply fall off an edge. It sticks to it and travels along it, and that is the whole reason the drip edge has a lip.
The gutter has pulled away from the board. Loose hangers or soft fascia let the back of the gutter tip outward, opening a gap that catches part of the roof and misses the trough. A rehang is usually a few hundred dollars.
The hangers are carrying the water. If the drips line up with the hangers, the straps are the path. Hangers that sit on top of the drip edge give water running along its underside something to follow straight back to the fascia. Hangers set under the drip edge stop it.
Get a free quote for your house
When the water is coming from higher up
If water only appears behind the gutter in winter, or during snowmelt, the gutter may be innocent. An ice dam holds meltwater on the roof, it backs up under the shingles, and it comes out at the eave behind everything. Ice dams are an attic problem first. A roof leak or failed flashing above can do the same thing year round, which is why a contractor should look up the roof as well as along the gutter.
The fixes, and what they cost
A drip edge extension or gutter apron. A strip of metal slid under the first row of shingles that hangs down into the trough. It is the fix for a missing or short drip edge, and for a gutter that sits a little too low. It is small money compared with anything else on the house, and it does not need the gutter to come down.
Rehanging the gutter behind the drip edge. If the gutter was fastened in front of the drip edge, the lasting fix is to lower it slightly, slip the back under the drip edge, and rehang it with the correct slope. It is repair work, typically within the range of a gutter repair rather than a replacement.
Rehanging on sound fascia. If the gap comes from the gutter pulling away, the hangers need resetting, and the board behind them needs checking first. Rotten fascia runs $7 to $22 a foot to replace.
What does not last: caulk. A bead of sealant bridging the roof edge and the gutter back looks like a fix and fails within a season or two. The gutter and the roof edge move with every temperature swing, and in a climate that swings as far as this one does, that joint tears. Metal that laps into the trough works because it does not rely on anything staying stuck.
What it damages if you leave it
Water behind a gutter wets wood that was never meant to be wet. The fascia goes first, then the soffit above it, then the ends of the rafters and the edge of the roof deck. Streaks and peeling paint on the siding below follow, and a window under the eave can take water around its trim. Down at the ground, all of that water lands against the foundation instead of leaving through a downspout, which is how some basement corners get wet. That end of it starts with the nearest downspout.
What a contractor should check
- Whether the back of the gutter sits behind the drip edge along every run
- Whether there is a drip edge at all, and whether it reaches the trough
- Whether the hangers sit under the drip edge or on top of it
- How sound the fascia is behind the wet stretch
- Whether the gutter has pulled away from the board anywhere
- Whether water is coming from above: ice dams, flashing or a roof leak
If a quote for this problem starts with new gutters, ask which of those it found. A new gutter hung in front of the drip edge will do exactly what the old one did.
Questions about water behind gutters
Why is water running behind my gutters?
Water is getting into the gap between the gutter and the fascia instead of into the trough. The usual reasons are a gutter hung in front of the drip edge instead of behind it, a roof edge with no drip edge or apron, a gutter that has pulled away from the board, or water clinging to the underside of the roof edge and wicking back.
Is water behind the gutter the same as overflow?
No. Overflow spills over the front when the gutter is full. Water behind the gutter runs down the wall side while the gutter itself may be half empty, which is why cleaning it changes nothing.
Can I fix water behind the gutter with caulk?
Only for a few months. The gutter and the roof edge move with every temperature swing, and a bead of caulk bridging them tears. The lasting fix is metal: a drip edge extension or gutter apron that laps into the trough.
What is a gutter apron?
A strip of bent metal that tucks under the first row of shingles and hangs down into the gutter, so water leaving the roof has nowhere to go but into the trough. It does the same job as a drip edge where the existing one is too short or missing.
Why does water only leak behind the gutter at the brackets?
Because the hanger straps give water a path. Water running along the underside of the roof edge meets a hanger, follows it back to the fascia and runs down. Hangers set under the drip edge rather than over it stop that.
Does water behind the gutter need a new gutter?
Almost never. It needs flashing, or a rehang so the back of the gutter sits under the drip edge. A new gutter hung the same way would do the same thing.
Get a quote
Tell us about the job, with a photo of where the water runs, and a local gutter contractor will call, text or email to set up a visit. The quote is free.
Related
- Why gutters leak at seams, corners and outlets
- Gutter repair
- Fascia and soffit repair
- Sagging gutters