Water that runs behind a gutter usually gets there because the roof edge has no metal flashing over the gutter, because the gutter has dropped or pulled away from the fascia, or because the trough overflows; resetting or resealing the gutter is gutter repair, but flashing, roof and rotted wood are not.
Why does water get behind the gutter?
Look for three causes. First, the shingles end at the roof edge with nothing to throw water into the trough. Second, the gutter sits too low or has pulled off the fascia, so the roof edge no longer reaches it. Third, the trough fills and spills back over its rear edge. The signs of a clogged gutter show whether the third one applies.
Quality Edge, a drip edge maker, shows the gutter hanging behind the drip edge or gutter apron, and says that without drip edge water gets behind the gutter and promotes rot and mold. Its sheet shows the drip edge lapping over the gutter. Amerimax's gutter installation sheet says the same from the gutter side: if the house has drip edge, slip the gutter under it. A gutter that has dropped or pulled away from the fascia no longer sits under that lap.
What does the building code say about drip edge?
The International Code Council printed the 2012 International Residential Code section R905.2.8.5, "Drip Edge." Its first sentence reads: "A drip edge shall be provided at eaves and gables of shingle roofs." Per the same text, the metal extends a minimum of 0.25 inch below the roof sheathing and up the roof deck a minimum of 2 inches, and underlayment goes over the drip edge along eaves. The ICC commentary adds that drip edge was not previously required for asphalt shingles unless the roofing maker's instructions called for it.
Two limits apply. This is the 2012 edition as the Code Council printed it, not necessarily the one your city uses. Each city adopts its own edition and amendments, so ask the building department what applies. And a code section tells you what a new roof needs, not what an older roof has.
Which fix is gutter repair, and which is not?
| What you find | Likely cause | Kind of work |
|---|---|---|
| Gutter sags or hangs away from the fascia | Loose or missing hangers | Gutter repair: sagging or loose |
| Water spills over the back edge when the trough is full | Debris or an undersized run | Cleaning first |
| Seam or corner drips onto the fascia | Failed sealant or joint | Gutter repair: leaking seams |
| No metal at the roof edge, shingles overhang bare | Missing drip edge or apron | Roof work, not sold |
| Fascia is soft or dark behind the gutter | Rot from long wetting | Carpentry, not sold |
| Stain inside the house at the exterior wall | Roof, flashing or wall leak | Roofer or inspector |
Rot is the reason to look early. When old gutters come off, Amerimax's sheet has the installer check the fascia board behind them and replace it if needed, and a soft board is carpentry that comes before any re-hang.
A worked example
Hypothetical: a front gutter drips onto the fascia only in hard rain, and the middle of the run has dropped. The shingles end with no visible metal. Hangers can be put back and the run re-set, which is gutter repair. Adding eave metal is roof work and is not part of a repair request. Photograph the gap from the ground, then see gutter cleaning versus gutter repair. A person decides which parts fit the request.
Scope and limits
Of the fixes in the table, re-setting a dropped gutter and resealing a joint fit a repair request; drip edge, roofing and fascia carpentry do not. See gutter repair requests, sagging gutters and who cleans gutters. Ground-level photos cannot show what sits under the shingles.
Get my price
If re-setting or resealing the gutter is the fix, start a gutter repair request and say where the water runs behind the gutter and in what rain. A person confirms the provider, scope and price in writing before payment.
Any US ZIP. No contact details until you have seen the estimate.
Sources
- International Code Council, 2012 International Residential Code R905.2.8.5 "Roof Drip Edge" change summary, 2012_irc_sigchanges.pdf, https://www.iccsafe.org/wp-content/uploads/errata_central/2012_irc_sigchanges.pdf, verified 2026-11-10.
- Quality Edge, "Drip Edge Perimeter Edge Flashing Quick Tips," REV. 11/22, https://qualityedge.com/wp-content/uploads/2023/12/DripEdge_InstallationQuickTips_1122-1.pdf, verified 2026-11-10.
- Amerimax, "Installing Metal Gutter Systems," https://images.thdstatic.com/catalog/pdfImages/0d/0dfd7e65-3be7-4964-b59f-b2ef635d4ca8.pdf, verified 2026-11-10.