Rebuilding worn roof valleys in Vancouver, WA

A roof valley is the inside corner where two slopes meet, and it carries more water than any other part of the roof. Every drop from both slopes funnels into it on the way to the gutter. That concentrated flow wears shingles faster, and any debris that collects there slows the water down and pushes it sideways under the shingle edges. Valleys are one of the most common leak sources we see.

Roof valley repair usually means more than replacing a few shingles. We strip the valley back to the decking, check for soft or rotted wood, install new ice-and-water underlayment down the full length, and rebuild it with either open metal flashing or a closed-cut shingle valley. The right choice depends on your roof, the amount of tree cover, and how the rest of the roof was built.

Why valleys wear out first

Water volume is the main reason. On a typical gable-and-valley roof, a single valley may drain the runoff from two large slopes. During a long Vancouver downpour, that water runs fast and steady, scrubbing granules off shingles in the valley center. Over years, the shingles there wear thin while the rest of the roof still looks fine. Valleys also see more foot traffic from gutter cleaning and roof work, which adds wear.

Installation errors play a big part too. If nails were driven too close to the valley center, every one of them is a potential leak. If the underlayment in the valley was standard felt instead of self-sealing membrane, it has less protection when water gets past the shingles. And a closed-cut valley with the top shingle cut wrong can direct water under the lower slope instead of over it. We see all three often.

Open metal vs closed-cut valleys

There are two common ways to finish a valley. An open valley uses a strip of shaped metal flashing down the center, with shingles cut back on each side so water flows over bare metal. A closed-cut valley runs shingles from one slope across the valley, then cuts the shingles from the other slope along a line just off center. Both work well when installed correctly over proper underlayment. We help you pick the one that fits.

• Open metal valleys shed needles and debris more easily
• Closed-cut valleys blend in with the shingle color
• Both need self-sealing membrane underneath
• Nails stay well back from the valley center
• We match the style to your roof and tree cover

How we rebuild a valley

We remove shingles several feet out on each side of the valley, pull old underlayment, and expose the decking along the full length. Soft or water-stained decking is cut out and replaced. Then we install self-sealing ice-and-water membrane down the valley, which seals around nails and holds back water that gets under the shingles. For an open valley, shaped metal flashing goes on top of the membrane. That layer is the real backstop.

Shingles go back on in the chosen style, with nails kept well back from the center line and the cut edge sealed where the method calls for it. We make sure the valley drains cleanly into the gutter at the bottom, since an overflowing gutter can push water back up under the lowest shingles. Before we leave, we clear debris from the valley and nearby roof surfaces and check the gutter below.

Keeping valleys clear after repair

Even a new valley will leak if it fills with needles, cones and moss. In heavily treed parts of Clark County, valleys can pack full in a single fall. Keeping them clear is the simplest way to protect the repair. Many homeowners pair a valley rebuild with routine gutter and roof debris cleaning, especially before the wettest months. We can point out the trees that drop the most on your valleys so you can plan trimming with an arborist.