Valley Flashing

Valley Flashing is a critical component of a pitched roof system and is installed at the areas where the two roof slopes meet. Roof valleys naturally collect and funnel large amounts of water down the roof during rain or snowmelt, making them one of the most vulnerable points for leaks.Valley flashing is designed to protect these intersections by creating a waterproof barrier that directs water safely off the roof and into the gutter system; without proper flashing, water can seep under the shingles, and lead to wood rot and interior water damage.

A “V” valley has a straight shape that directs water down the center of the valley, providing a straightforward channel for water runoff. A “W” valley has a raised ridge in the middle, forming a “W” shape; this helps guide water away from both roof planes along separate paths. There are two types of valley flashings used depending on the customers aesthetic preference and budget. The first type is known as an open valley; this is where a piece of aluminum or copper is laid along the valley and left visible, with shingles trimmed on each side stopping short of the center. This allows water to flow directly onto the metal, minimizing the risk of buildup or blockage.

The second type of method is called a closed valley; this is where the shingles from both sides of the slope extend across the valley and meet in the middle covering the flashing underneath. In areas with heavy rain or snow, open valleys are often preferred due to their durability and water-shedding performance. In summary, valley flashing is essential for preventing leaks in one of the most water-exposed areas of a pitched roof; choosing the right valley system will play a pivotal role in the durability and lifespan of your roofing system.