Roofing valleys are the seams that connect adjacent roof planes. They can also help improve the drainage of the roof. However, they can be costly to install. If you want to reduce the cost of your project, you may want to avoid using them. Instead, consider the closed cut style. These valleys are typically more economical.

They improve roof drainage

Roofing valleys help improve roof drainage, but they can also cause leaks. The valleys channel a lot of rain, snow, and debris. The underlayment in these areas can also become weakened, causing leaks. Fortunately, there are steps you can take to prevent leaks and repair existing problems.

The type of roofing valley you choose depends on your home and climate. Open valleys are more effective for houses in cooler climates and at higher elevations. They channel water away quickly from a house because it will flow around both sides of the valley. Without valleys, water can pool on the roof and become trapped underneath shingles, behind the drip edge, and beneath roofing felt.

Dead valleys can be hard to notice, but they can cause serious problems. Debris accumulated in the dead valley can rot the roof and lead to leaks. To remedy this problem, you should install a metal pan in the valley. These metal pans are especially helpful in the corners of the roof.

A dead valley can form when opposing roof slopes intersect. Water flows downhill through this intersection, which creates a trough. However, if water is allowed to pool in the valley, it can cause damage to the house and attract pests. Moreover, a dead valley can lead to pitch spots, which are areas of insufficient drainage.

They are expensive to install

If you don’t have a roof valley on your home, consider getting one installed. These structures will catch water rushing down two planes of the roof and channel it away. But they’re also prone to leaks, particularly if water runs up the opposite side. Other causes include ice and snow buildup or traffic on the roof. Because of these risks, all roof valleys should be installed with a waterproof underlayment system. It’s best to use a 36-inch-wide bituminous membrane in 10 to 15-foot lengths.

Although there are many types of roof valleys, the most popular ones are made of fibreglass. Fibreglass is cheap, lightweight, and resistant to UV rays. But it isn’t as water-tight as its modern counterparts. Older fibreglass products are prone to cracking and splitting, and water can leak through tiny holes. While damage that occurs due to age can often be repaired, if it’s too severe, you might need to have the entire valley replaced.

While open valley roofing is preferred by most roofing contractors, closed valley roofing is still used by some homeowners. However, many shingle manufacturers recommend a closed roof valley. Ask your roofer for advice on which type is best for you. An open roof valley is simpler to install, but it is more expensive.