Roof valleys

Normal function

A valley collects and directs large volumes of water toward the eave while the lining and shingle layout keep water from entering the assembly.

What a homeowner may notice

• Debris, exposed lining, rust, open seams, cut shingles, nail heads, or displaced valley shingles.
• Water stains below a valley after a storm, even when field shingles look sound.
• Worn valley channels, incorrect shingle cuts, or nails too close to the centerline.
• Water overflowing or splashing at the valley-to-gutter transition.

Professional inspection

Clear loose debris without damaging shingles, inspect the valley from the eave upslope, check the lining and shingle cut, then correlate with attic stains. Look for concentrated wear and fastener placement.

Repair or replacement path

Choose an approved open or closed-cut detail for the roof covering, replace damaged lining and underlayment, maintain side laps and nail setbacks, and rebuild the shingle courses with proper water flow.

Typical materials and equipment

Valley metal or membrane, leak barrier, underlayment, matching shingles, roofing nails, flashing snips, chalk line, and debris containment.

When to act

A leaking valley can wet deck and insulation quickly; treat active leaks as urgent.

What moves the price

Valley length, roof pitch, roof covering type, ice/water detail, difficult access, hidden deck rot, chimney/dormer intersections, and matching.