Roof Valley

Why Does My Roof Valley Look Different from My Neighbor’s?

Roofing is one of the most complicated and costly endeavors involved in building a new home. A new roof is expected to last for decades, or even your whole lifetime. The choices you make now are going to stick with you for a longtime after you pay for them. You’d better be sure you’re getting what you want! Take a look at different roofs in your neighborhood and beyond. You might notice that some of them are pieced together differently from others. In particular, the way the roof valley is covered might look very different from house to house. What does this mean, and how does it impact the quality of your new St. Augustine roof?

A roof valley one of the parts of a roof where two planes join to form a canyon-like shape down which water can trickle to the gutters. A roof valley is also one of the most sensitive parts of a roof that’s susceptible to weather damage if it isn’t properly protected. Fortunately, there are a couple of good ways to do this.

Roof Valley Types Defined

Close Valley Roof
Several closed cut roof valleys

There are a few types of roof valleys to know:

  • Closed cut valleys
  • Closed woven valleys
  • Open (or “exposed metal”) valleys

“Closed” refers to a roof valley that is covered entirely by the primary roof covering material (like your asphalt shingles) with no other materials present. The two planes of the roof are joined together to form one contiguous piece. This results in the underlayment in the valley being fully closed off from the elements outside of the roof.

There are two types of closed roof valleys: cut and woven.

A cut roof valley actually looks one long, uninterrupted stretch of roofing. It looks like a big shingle blanket carefully laid down across the roof deck. A woven closed valley, however, looks like the two panels of shingles have been elegantly intertwined at the edge. This still has the appearance of one large piece, but with an attractive seam.

Closed Woven Roof Valley
A woven roof valley

On the other hand, an open roof valley means that the two planes of roofing material aren’t conjoined. Instead, they approach the edge of the valley and stop. Along the valley, the roofer will install a specially-molded piece of roofing material (often metal; copper is popular, though expensive choice) that runs down the center of the valley and secures into the roof underlayment.


Open Valley
An open roof valley

Roof Valleys: Closed vs Open

Now, with two unique options in roof valley installation comes two unique philosophies among roofers.

Closed valley roofs have risen to popularity in recent years because they’re simply cheaper and easier. A competent roofer can install a closed valley roof that’ll securely protect your roof underlayment and deck from the elements. The primary disadvantage with closed roof valleys is that they don’t easily allow snow, ice, and debris to slide down the edge of the roof. As a result, heavier weather conditions can put extra stress on your roof, causing your shingles to lose granules and potentially contributing to the formation of ice dams.

This disadvantage makes the open valley roof seem like a better choice, but here in Florida, we just don’t get snow! An open valley roof simply costs more because the roofer has to purchase an additional piece to complete the corner and install it. However, many homeowners consider open valley roofs to be more attractive and clean looking, with a nice seam between roof panels.  

Roof Valley Craftsmanship: What to Watch Out For

Roof Valley

So far, we discussed the pros and cons of each roof valley type. But we’ve been doing this assumption that your contractor did a good job installing your roof. Since the roof valley is very sensitive, it’s critical that it be installed properly and securely. This is an easy part of the roofing process to mess up, so let’s go over some things you can look for as a homeowner. 

A good open roof valley is installed with a metal piece or some synthetic material. If your valley appears to be made of a covering or cheap roof lining, then it’s probably not actually protecting your home from water. You can look to see whether the shingles are securely sealed to the edge of this lining; if they aren’t, it’s easy for water to splash across from one side to the other and slip under the shingles.

On a closed valley roof, look to the steeper plane of the roof and check the direction of the shingles. They should be running close to parallel to the direction of the valley, while the shingles on the other plane should be running towards the valley, with their corners clipped at the seam. This way the water trickling down from the more shallow plane can run off of the steeper one rather than splashing back into the valley.

What do you think? Which style of roof valley do you like better? Each one has its advantages, and we’re experts in both. If you’re getting a new roof put over your head, give your neighborhood roofers a call at Elite Remodeling Services. We’ll size up your roof and let you know the best roof valley solution to choose for your home.


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