The Importance of Roof Valleys in Asphalt Shingle Roofing—and How to Build Them Right

When it comes to defending your home against the elements, your roof does the heavy lifting. While shingles, flashing, and ventilation usually grab the spotlight, one of the most crucial yet overlooked features is the roof valley. Roof valleys aren’t just a design detail they play a key role in keeping your home safe from leaks and water damage. As a leading roofing contractor in Hattiesburg, MS, Matlock Roofing & Construction knows that the longevity of a roof often depends on how well its valleys are constructed and maintained.

Defining Roof Valleys

A roof valley is created where two sloping roof planes meet, forming a channel that directs rainwater and melting snow toward your gutters. Because they carry a concentrated flow of water, valleys are exposed to more stress than other parts of the roof. If they’re not installed or protected correctly, they can become prime spots for leaks and water intrusion.

Common Types of Roof Valleys in Asphalt Roofing

1. Open Valleys

These valleys use exposed metal flashing, typically made from aluminum, steel, or copper, to form a visible drainage channel. Shingles are cut to line the flashing.

Benefits:

• Superior water drainage

• Long-lasting protection

• Easy to inspect and clean

2. Closed-Cut Valleys

One set of shingles runs across the valley, while shingles from the other side are trimmed in a clean diagonal line down the valley center.

Benefits:

• Sleek, uniform look

• Seamless blend with asphalt shingles

• Effective water resistance

3. Woven Valleys

Here, shingles from each slope are interlaced, creating a woven effect over the valley. This traditional method works well in mild climates.

Benefits:

• Cost-efficient

• Durable in moderate weather

• Matches classic asphalt installation methods

Note: Woven valleys aren’t recommended in areas with heavy rainfall or snow since water and debris can easily build up underneath the weave.

Why Proper Valley Construction Matters

Valleys are one of the busiest water-handling zones on your roof. Any mistake during installation can cause serious issues.

• Heavy Water Flow: Because valleys channel so much water, poor workmanship—like incorrect nailing or flashing—can quickly lead to leaks.

• Ice and Debris Buildup: In colder regions, valleys are prone to ice dams. In warmer climates, leaves and debris can clog drainage and create moisture problems.

• Accelerated Shingle Wear: Shingles in valleys endure constant water flow, making them more prone to granule loss, curling, and early deterioration.

Materials That Protect Roof Valleys

A dependable roofing contractor won’t rely solely on shingles to protect valleys. Extra materials reinforce these areas:

• Ice and Water Shield: A waterproof membrane placed under shingles or flashing.

• Metal Flashing: Guides water flow in open valleys and protects the seam.

• Roof Cement/Sealant: Provides reinforcement in tight areas but should never replace proper installation.

Maintaining Asphalt Roof Valleys

Even when installed correctly, valleys require upkeep:

• Inspect them after storms for damage or debris.

• Keep them clear of leaves, branches, and pine needles.

• Look for signs of granule loss or shingle wear.

• Avoid stepping directly on valleys, as foot traffic can weaken them.

When to Call a Roofing Contractor

Roof valleys are not a DIY project. If you notice leaks, damaged shingles, or visible wear, reach out to a licensed roofing contractor in Hattiesburg, MS. Professionals have the expertise to repair or replace valleys the right way, preserving your roof’s integrity.

Final Word

Though often overlooked, roof valleys are essential for the durability and performance of an asphalt shingle roof. By channeling water safely off your roof, they protect your home from leaks, moisture, and long-term damage. Whether you need a new installation, repair, or inspection, choosing the right contractor makes all the difference.

At Matlock Roofing & Construction, we take pride in quality workmanship and reliable roofing services. As a trusted roofing contractor in Hattiesburg, MS, we ensure every roof valley is designed and installed with precision for maximum protection. Call us today at 601-299-4219 to schedule your consultation and see why homeowners trust us for lasting roofing solutions.