This is most common in homes built before about 1940. Valleys concentrate the runoff from two slopes into one narrow channel. Leaves and debris collect there too, which holds water against the roof.
1Why valleys fail
- Old metal rusts. Galvanized valley metal wears through over decades.
- No lining at all. On many old roofs, later layers of shingle were simply woven across the valley with nothing underneath.
- Debris. Leaves and needles pile up in valleys, slow the water and keep the area wet.
- Ice. In cold climates, valleys are a common place for ice to build and push water under the shingles.
2How to check
- Look from the groundWith binoculars, look for rust, exposed metal edges, debris buildup, or shingles that look worn or patched along the valley.
- Look inside below the valleyA stain on the ceiling or wall below where two rooflines meet is the typical sign.
- Check the atticFollow the valley in the attic and look for stains or soft wood along it.
3Fixing it
Do it yourself
- Spot the signs from the ground and the attic
- Keep valleys clear of debris from a safe position, or have it done
- Ask for a new valley lining in any reroof quote
Hire a pro
- Strip the shingles along the valley
- Repair any damaged deck
- Install a new valley lining and underlayment
- Reinstall shingles to the valley correctly
Valleys are slippery, especially with debris in them. Don’t walk the roof to clean or inspect them.
4What drives the cost
The price depends on how many valleys there are and how long they run, the pitch and height of the roof, whether the deck along the valley is damaged, and whether it’s done as a standalone repair or as part of a reroof. During a reroof, a new valley lining is a small line item.
Talk to a roofing contractor who will check what’s under the valley shingles, not just patch the surface.
877-360-46575Questions
Can a valley be repaired without a new roof?
Often, yes. A crew can strip and reline a valley as a repair. If the rest of the roof is near the end of its life, it’s usually better done as part of the reroof.
Why does my valley leak only in heavy rain?
Heavy rain sends the most water down the valley at once. If the lining underneath is gone, that’s when it finds its way through.
Do I need to clean my valleys?
Debris in valleys holds water. Under heavy tree cover, have them cleared, without walking the roof yourself.
Written by Jaylan Jones. I Like To Exterior Services earns a referral fee when a call connects to a contractor. See our business-model disclosure.
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