One of the many structural details you should consider when replacing or installing a new roof are the valleys. You have two options on how to seal this area, namely either via a closed or open valley method. How a valley is sealed depends on certain factors, including how the contractor you’re working with installs the roofing underlayment and shingles.
In this post, Feller Roofing of New Braunfels shares the difference between closed and open roof valleys.
Closed Roof Valley
Prior to installation, the underlayment is installed over the entire roof deck. Usually, there’s a self-adhering ice and water shield or a second underlayment installed that covers the other parts of the roof that the initial underlayment can’t cover. This self-adhering underlayment is called the valley lining.
In the closed valley method, the shingles are installed onto the roof. This essentially extends the asphalt shingles through the valley so the roof surface covers or closes the valley area, hence the name. The shingles completely cover the underlayment, and they become the valley lining itself.
Open Roof Valley
This is almost the same as the closed roof valley method, except a pre-bent metal valley lining is installed instead of a secondary roof underlayment. Once the shingles are installed, they don’t run through the valley area. This leaves a metal strip or line on the surface of the roof that serves as the valley line.
Closed or Open Roof Valleys?
While both are viable methods to finish the roof, the closed roof valley is the more practical choice due to several factors. This method looks better as the shingles are laid out in a manner that’s uninterrupted by any metal lining. It’s also less susceptible to water damage as the shingles will naturally channel water away from the roof. Thus, closed roof valleys extend the time between your roof repair projects.
Closed roof valleys are also more affordable as installing a metal lining costs extra. That said, an open roof valley is a good option if you want to the metal strip to serve as an architectural detail on the roof. It’s important, however, to properly waterproof this area with flashing and sealants.
At Feller Roofing of New Braunfels, we offer complete residential roofing services. Call us today at (830) 214-2400 to learn more about our services. We are roofing experts in New Braunfels, TX.