Best Ways to Shingle a Valley

By Amanda Lutz Updated May 16, 2024

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Conventional roofs have lots of ridges and valleys, and properly shingling them can extend their life span and keep water out. The process to shingle a valley is relatively straightforward, but you must complete it precisely to avoid the risk of water damage. Read about the three most popular methods of shingling a roof valley and learn how to install shingles in our guide.

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What Are Roof Valleys?

Conventional asphalt roofs have many different faces. When two downward-sloped faces meet, they form an interior angle called a roof valley. Water often collects at greater concentrations along roof valleys before it funnels into the nearest gutter.

If you need to repair or install shingles along roof valleys, consider the two potential complications below.

Keep these concerns in mind as you decide which shingling method to use.


Materials Needed to Shingle a Valley

Installing your own shingles is a simple task, especially if you’re comfortable with climbing onto your roof. The job requires tools and materials you probably already have at home.

Essential Materials

Essential Tools

Gather all of your supplies before beginning the project so you don’t have to pause in the middle of the work.


Preparing the Roof Valley

If you’re replacing existing shingles on your roof valley, then start by removing old materials. Pull off the shingles surrounding the section you want to replace. Remove damaged three-tab shingles entirely instead of only cutting away the damaged portion. Cut and remove the underlayment material too.

Once you’ve removed old materials, inspect the sheathing below for damage such as gaps, softened areas, and visible rot. If you see damage, cut away the problematic sheathing and some of the undamaged wood that surrounds it, which might contain an excess of moisture. Replace the damaged sheathing.

If there isn’t rot or damage and you’re ready to move forward with installing shingles, then clear the area of fragments, dirt, and shingle granules with a brush.


Valley Shingling Methods

The most important choice to make before you begin shingling is which method you want to use to cover the valley. If you’re replacing just one valley, the best strategy is to identify which style your roof already features and replicate it. If you’re installing an entirely new roof, you have more freedom to choose a method that aligns with your style and skill level.

Three of the most popular shingling options are the closed-cut method, open valley method, and weave method.

Closed-Cut Method

The closed-cut valley method of shingling is common for roofs with architectural shingles and amounts to a single layer of shingles that runs along the roof valley. You’ll cut away excess material during installation to create a crisp line down the “V” of the valley.

This method is simple, fast, and cost-effective since it doesn’t require metal flashing or many shingles. Complete the process by sealing the cut edges with roof cement to prevent water leaks. Any mistakes during this process could leave your roof vulnerable to water flow damage.

Open Valley Method

If you choose the open valley shingling method, you’ll cover the underlayment with metal lining that remains visible. This method is a great choice if your home has metal valleys. The flashing is very durable, so it can work in nearly all environments and climates.

There are some disadvantages to this method, though. Metal flashing can be expensive, and it’s easy to damage if you nail too close to the valley or bend it during installation. This method is not ideal if other roof valleys aren’t open.

Follow the instructions below to install shingles using this method:

  1. Insert metal flashing between the underlayment layer and the shingle layer. Be sure to mark the shingles where the edge of the flashing rests.
  2. Cut away the excess shingle material to give the metal flashing a clean line. The shingles should cover the nails that hold the flashing in place. You can install a row of shingles that run parallel to the valley line for a cleaner look.

Weave Method

You don’t have to cut shingles if you choose the weave method, also called the woven valley method. This makes it tougher for water to penetrate below the shingles as there are no seams or weak points. This method leads to an especially durable product with a seamless look.

There are some disadvantages to choosing the weaving method. It creates a slight hollow between the sloping bend of the shingles and the sharp bend of the valley underneath. This can increase the risk of damage, splitting, puncturing, or ripping if someone steps on the valley.The weave method involves installing shingles from side to side and overlapping the edges. The rows then crisscross over the center of the valley. Make sure to press down on the valley centerline to avoid bridging, or hollow spaces between shingles and the roof deck. This process is slower than other installation methods but gives the roof a seamless pattern and helps to prevent roof leaks.


Step-by-Step Guide to Valley Shingling

Once you decide which installation method is right for your home and style, you can start ordering needed materials and setting aside time for the project. You can reshingle a roof valley in just a few hours if you have relevant experience, so the project should take less than a day.

Follow these steps to shingle your roof valley with the closed-cut method:

  1. Apply underlayment along the roof sheathing to create a water shield. Lay felt paper or another underlayment material flat along the roof’s surface and position the edges away from the valley so there isn’t a seam. Nail the underlayment in place, and bend the material tightly into the valley so there are no hollows. This material should cover all of the underlying sheathing to prevent rot.
  2. Install the first course of shingles. Start at the bottom of the roof near the drip edge and eaves and move toward the top of the valley. Use four nails per shingle, and place them above the tabs. Be sure to drive the nails in straight 1/2 inch above the tabs and along the tar line. Once you reach the roof valley, allow the shingle to overlap the valley and nail it in place. Adjust the nailing position so you never drive a nail straight into the point where the two roof planes meet.
  3. Lay out and install each row of shingles on one face. Continue to lay out and install rows of shingles, one above the other. Place them so each subsequent row covers the tar line and so the nails of the row below are totally covered. Excess shingles should cover the valley for each row. Use chalk to mark a straight line that’s approximately 1 or 2 inches to the side of the valley. This will act as the cut line for the second face’s asphalt shingles.
  4. Install shingles on the other face. Once you’ve reached the ridgeline for one face, move to the bottom of the face on the other side of the valley and install each row of shingles. Allow excess shingle tabs to sit across the valley without nailing them in place. Continue until the entire face is covered.
  5. Cut away excess shingle material. Begin at the bottom of the roof valley and use snips or shears to cut unsecured, excess shingles from the overlapping face along the chalk line. Cut the valley slowly and carefully so that you’re left with a crisp, straight line. Apply roof cement along the underside of the cut line and press the shingles down to secure them in place.

If you choose the open valley or weave methods, your final steps will vary. Add your underlayment first no matter which roof installation method you choose.


Common Mistakes When Shingling Valleys

There are some mistakes that you can easily make while shingling a roof, especially if you’re unfamiliar with the process. Be mindful of the potential errors below.


Our Recommendation

Installing or replacing shingles along roof valleys will help you to keep water out of your house. Once you’ve researched different methods for installing shingles, choose the right fit for your home and install them as part of a do-it-yourself (DIY) project. We recommend always working with a partner, especially if you have a difficult-to-navigate roof. Hire a roofer to shingle your roof valley if you’re not comfortable performing the installation.


How to Shingle a Valley FAQ

What is the best way to shingle a valley?

The best way to shingle a roof valley depends on your budget and roof style. Open valley roofing is popular and incredibly durable, but it can be more expensive than other methods.

How do you calculate shingles for a valley?

Calculate the shingles for a valley by measuring the length of the valley. You’ll need at least two shingles per linear foot if you’re installing shingles as part of a roof build. Expect to need more shingles if you’re replacing or repairing a damaged roof valley.

Which is better, an open valley or a closed valley?

An open valley lasts longer and has greater aesthetic appeal, but closed valley shingling is more cost-effective. The best type of valley depends on the homeowner’s preferences.

Can I shingle a valley myself?

You can shingle a roof valley by yourself, but it’s safer to work with a partner or group of people. Hire a roofing contractor if you’re uncomfortable with roof valley installation.