The line where the shingles end and the eavestrough begins decides whether roof water lands in the trough or behind it. This guide shows five checks you can make from the ground, what each sign means, and which trade should fix it.
In This Article
The roof-edge geometry that keeps water in the trough
Three parts have to line up. The shingles should project a short distance past the roof edge, commonly under about 2 centimetres (3/4 inch). A metal drip edge along that border should lead water outward. And the trough should sit just below and outside it, so the runoff falls into the middle of the channel.
Get the overhang wrong and the water misbehaves. Too little, and it curls back and runs down the fascia behind the trough. Too much, or shingle tabs that droop, and drips leap past the trough or hang up on the edge and carry debris with them. In snow country, installers also commonly set the front lip just below the line of the roof slope, so sliding snow passes over the trough and does not strike it.
Five checks you can make from the ground
- Sight along the eave from each end. Look for curled, cupped or drooping shingle tabs, and for a ragged edge where the line should be straight.
- Look for water tracks on the fascia. Dark, damp or peeling paint on the top of the fascia, just under the trough, means water is getting behind it.
- Watch the roof in a downpour. Stand under cover and see where the water lands. A stream that jumps the trough at a valley or below a dormer is overshooting.
- Read the grit. A light dusting of shingle granules in the trough is normal. Thick drifts or bare patches on the shingles suggest the roof is wearing out.
- Scan the junctions. Where a sloped roof meets a wall, a small bent metal piece called kick-out flashing should push water into the trough. If it is missing, look for streaks running down the siding below.
Do not climb onto the roof to check any of this. Shingles crack underfoot, and roof work belongs to roofers.
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What each sign usually means
| Sign | Likely cause | Who normally fixes it |
|---|---|---|
| Drooping tabs dipping into the trough | Aged or curled shingles | Roofer |
| Water tracks and peeling paint on the fascia | Too little overhang or a missing drip edge | Roofer, plus a fascia repair |
| Overshoot at valleys and dormers | Concentrated flow from a large roof area | Eavestrough installer, with a diverter |
| Heavy granule drifts | Shingles near the end of their life | Roofer to assess, cleaning crew to clear |
| Streaks below a roof-to-wall junction | Missing kick-out flashing | Roofer |
| Bent front lip after snow slides | Trough set too high, or a weak hanger | Eavestrough installer |
What you can do, and what to hand over
You can clear the debris that gathers at the edge, watch the roof in the rain, and take dated photos of any track or stain. Do not trim shingle edges, bend tabs into place, or smear sealant along the edge to fake an overhang. These fixes trap water instead of shedding it.
A roofer can adjust or add drip edge, or fit a gutter apron, a metal flashing that bridges the gap between the roof edge and the back of the trough. An eavestrough installer can reset the trough height and slope, add hangers and fit valley diverters. The gutter pitch guide shows why slope matters so much once water reaches the trough. Rot at the top edge of the fascia needs attention first, and the guide to fascia and soffit maintenance covers what to look for.
Keeping the edge clear year to year
Clean the trough after the spring seed drop and again in November, and note what you find each time. A steady increase in granules is an early warning about the roof.
Be careful with guards. Some types slide under the first course of shingles, which can lift them and may raise questions with your roofing warranty. Ask the installer, and check your warranty terms, before picking that style. The comparison of gutter guard types sets out the trade-offs.
D&D Home Services handles gutter cleaning and quotes eavestrough installation. Shingle and flashing repair is roofing work, so ask a roofer about those. Quotes are free and confirmed in writing.
Key Takeaways
- Shingles, drip edge and trough must line up so roof water falls into the middle of the trough.
- From the ground, check for drooping tabs, tracks on the fascia, overshoot at valleys, heavy granule drifts and missing kick-out flashing.
- Never trim shingles or use sealant to fake an overhang. Ask a roofer for drip edge or apron fixes.
- Some guard styles slide under the shingles, so check installer and roofing warranty terms first.
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