Roof Valleys

Whenever two sections of a roof come together, they form a valley. During a rainstorm or snow melt, water from both roof slopes flows into this channel before draining into the gutter system.

Because roof valleys handle such a large volume of water, they receive more wear and tear than most other areas of the roof. For this reason, valleys require additional protection beneath the shingles, including ice and water shield, and must be installed carefully to ensure proper drainage.

A properly installed roof valley helps move water safely off the roof while protecting the roof deck from moisture damage.

Types of Roof Valleys

There are several ways to install a roof valley. The best method depends on the roof design, roofing material, manufacturer installation requirements, and the contractor's preferred installation practices.

- Open Metal Valley

An open metal valley uses prefinished metal flashing installed down the center of the valley. The shingles are cut back on both sides, leaving the metal exposed to carry water safely off the roof.

A properly installed open metal valley includes hemmed or clipped edges that help direct water into the valley, strengthen the metal, and create a clean finished appearance. Open metal valleys provide excellent drainage and are designed to handle the large amount of water that flows through a roof valley.

At VanderLaans, we install traditional open metal valleys with hemmed or clipped edges. We do not install California-style valleys.

- Closed-Cut Valley

A closed-cut valley is created by extending shingles from one roof plane through the valley while shingles from the adjoining roof plane are cut neatly along the valley line. This creates a clean, uniform appearance with no exposed metal.

When installed according to the roofing manufacturer's specifications, closed-cut valleys provide excellent water protection and long-term performance.

- California Valley

A California valley uses an additional shingle installed up the center of the valley instead of cutting shingles from both roof planes. This installation method eliminates exposed metal and is accepted by some roofing manufacturers.

Although California valleys are used in some areas of the country, they are less common in West Michigan. At VanderLaans, we prefer traditional open metal valleys because they provide excellent water management and a clean, professional appearance.

- Woven Valley

A woven valley is created by weaving shingles from both roof planes together across the valley.

While woven valleys were commonly used with older three-tab shingles, they are generally not recommended for today's architectural shingles because of their increased thickness. In many cases, woven valleys do not meet the installation requirements of modern asphalt shingle manufacturers and may affect warranty coverage.

For these reasons, woven valleys are rarely used on modern residential asphalt shingle roofing systems.

Common Valley Problems

Because roof valleys carry more water than almost any other part of the roof, they are one of the first areas where problems may develop.

Common issues include:

• Damaged or missing shingles

• Improperly installed valley flashing

• Debris buildup that restricts water flow

• Ice dam formation during the winter

• Cracked sealant or deteriorated roofing materials

• Improper installation that allows water to work beneath the shingles

Regular roof inspections can help identify these issues before they result in costly water damage.

Typical Cost

Roof valleys are included as part of a complete roof replacement and are not typically priced separately.

The installation method, roof design, number of valleys, and roofing materials all affect the overall cost of the roofing project. Because valleys handle such a large volume of water, proper installation is more important than choosing the least expensive installation method.

Benefits

• Safely directs large amounts of water off the roof

• Helps prevent roof leaks

• Protects the roof deck from moisture

• Improves roof drainage

• Works together with ice and water shield for added protection

• Helps extend the life of the roofing system

• Provides long-term weather protection

Why It Matters in Michigan

Michigan roofs are exposed to heavy rain, lake-effect snow, ice, and repeated freeze-thaw cycles throughout the year. These weather conditions place constant stress on roof valleys because they collect water from multiple roof slopes.

Properly installed valleys, combined with ice and water shield and quality roofing materials, help protect one of the most vulnerable areas of the roof while providing reliable water management throughout every season.

Our Recommendation

At VanderLaans, we install roof valleys in accordance with the roofing manufacturer's specifications and the unique design of each roof.

We believe a properly installed valley is one of the most important details of a quality roofing system. Whether your roof requires an open metal valley or a closed-cut valley, our goal is to provide long-term protection, excellent water management, and a clean, professional appearance.

Did You Know?

Although roof valleys make up only a small portion of your roof, they often carry more water than any other area during a storm. That's why proper valley installation is one of the most important details in a roofing system and one of the first areas professional roofers inspect for signs of wear or potential leaks.