Have you ever been in a situation where you have to install shingles on your roof?

And the only thing that stands between you and a perfectly finished job is how to properly do it in a valley?… You’re not alone! 

george nicola

By George Nicola (Expert Stager)

Table of Contents

How-To-Install-Shingles-In-A-Valley-Effectively
How To Install Shingles In A Valley Effectively

Installing shingles in valleys can be tricky, but with professional help and some patience, it can be done. 

Here’s an overview of everything you need to know about installing shingles in valleys so that your next project is successful! 

Why Is Installing Shingles In A Valley Important?

One of the most integral parts of roofing is installing shingles, especially when it comes to areas that have valleys. 

Valleys create an area where two roof planes meet and can be challenging for someone who is not experienced in roofing installation. 

Professional roofers are equipped with the knowledge and tools necessary to take on this type of job. A proper installation of shingles will help prevent water infiltration into the home. 

DIY Steps To Install Shingles In A Valley

Installing shingles in a valley is a multi-step process that requires patience and attention to detail. Here are the steps you should take when installing shingles in a valley: 

  1. Mark out your valleys by measuring and marking the center line with chalk or marking tape.
  2. Install ice and water shield membrane along the bottom edge of your roof, overlapping sections at least 6 inches as you go up.
  3. Install felt paper along the edges of your roof, overlapping sections at least 18 inches long.
  4. Install starter strips at the bottom of both sides of the valley, making sure they’re aligned straight across from each other so it looks symmetrical.
  5. Install the shingles across the top of the valley, starting on one side and working your way to the other. Make sure you overlap each row by at least 6 inches.
  6. Cut out pieces of shingle and install them in the sides of the valley, again making sure they’re aligned straight across from each other for symmetry.
  7. Seal all edges with roofing cement or caulk to prevent water leakage and ensure a secure seal.
  8. Inspect your work and look out for any potential problem areas that could lead to leaks down the road.

Now that you know the steps involved, let’s go into the details of things to do before installing roof shingles and the process of installation. 

Things To Do Before Installing The Shingles In A Valley

1. Choosing The Right Materials

It’s important to choose the right shingle materials when installing them in a valley. You need materials that are robust enough to withstand heavy water flow without breaking down or tearing apart. 

That’s why most professionals recommend using laminated architectural asphalt shingles with fiberglass matting for top-level performance and longevity under harsh weather conditions. 

They are commonly known as composition roofing and are available in various sizes and styles so you can find one that fits your aesthetic needs as well as your budgetary constraints. 

2. Preparing The Valley

Before you begin installing the new shingles, you must first prepare the area by removing any old shingle material that remains from previous installations. 

It’s also important to check for signs of wood rot or damage where two roofs meet at an angle before replacing any materials. 

The last step is to ensure that all surfaces are clean and free from dirt and debris before beginning installation. This will help ensure that your new shingle install stays secure over time. 

Process Of Installing Shingles In A Valley

1. Applying Underlayment

The first step in installing shingles in a valley is applying underlayment. Underlayment helps protect against leaks by providing additional waterproofing before the shingles are installed. 

It also helps keep moisture away from the wood sheathing, which could cause rot or decay over time if left unchecked. 

Professional roofers will typically use either felt paper or rollable asphalt-based underlayment depending on what type of shingle they plan to use. 

2. Installing Starter Shingles

Once the underlayment has been applied, starter shingles should be installed along both sides of the valley—this helps ensure that all subsequent shingle rows will be properly aligned with each other. 

The starter strips should overlap one another by about 3 inches (7 cm) at the top edge of each strip (the edge closest to the ridge). 

If a mineral-surfaced cap sheet is being used as part of the overall installation, it should also be placed along both sides as well. 

3. Laying Out Shingle Courses

The next step is laying out and nailing down each course of shingles within the valley itself. Each row should overlap its predecessor by approximately 6 inches (15 cm). 

This provides adequate coverage while still allowing water to flow freely off both sides of the roof plane without any pooling occurring in between courses. 

When placing nails, care should be taken not to drive them too close together. This could cause damage to individual tabs and result in premature failure due to wind uplift or ice dams during cold weather conditions. 

Professionals typically space nails about 1 inch (2 cm) apart for optimal results when installing architectural-style shingle products. 

4. Sealing Flashings

To ensure a secure installation, flashes of aluminum or copper should be fitted around all points of penetration (eaves/fascia boards) near valleys to avoid water infiltration.  

Self-adhered membrane flashings can also be utilized for vents and skylights depending on the product selected for the project overall. 

However, only certified professionals are able to provide sound advice as no two projects will share exactly the same specifications! 

Benefits Of Working With A Professional Roofer

Benefits Of Working With A Professional Roofer
Benefits Of Working With A Professional Roofer
  • These professionals are highly experienced in completing complex installations correctly from start to finish without compromising quality along any part of their work process.
  • DIYers can find it difficult to stay abreast of new code requirements, the right materials for installations, or modern types and styles.
  • Without formal training in these areas, your roofing projects may not measure up to industry standards.
  • By collaborating with an expert, you can also ensure that all relevant warranties remain valid.

This way, your investment is safeguarded from any potential defects down line due to unforeseen circumstances beyond anyone’s control during the construction stage(s). 

Key Take-Away For Homeowners

Installing shingles in a valley is not an easy task and requires precision, skill, and experience. 

While it can be completed by DIYers with the right tools and guidance, it’s often best left to professionals who have extensive knowledge of roof installation techniques. 

With their help, you’ll get a quality job done quickly so your home or business will stay protected from the elements for years to come. 

Note – If you’re considering installing new shingles in a valley yourself make sure you follow all safety protocols before beginning any work on the roof.  

Alternatively, reach out to local professional contractors who specialize in residential or commercial roof repairs today! 

FAQs - How To Install Shingles In A Valley?

How do you shingle a close Valley?

To shingle a closed valley, you will need to cut the shingles into half lengthwise and then install them on opposite sides of the valley. 

Which side of the valley do you shingle first?

When installing shingles in a valley, start with the outside edge and work your way toward the center along both sides of the roof. 

Should roof valleys be sealed?

Yes, roof valleys should be sealed to prevent water infiltration. Use butyl tape or flashing cement to seal the seams between materials. 

Do you need metal in the roof Valley?

Metal is not usually necessary in a roof valley unless specified by local building codes or an engineer’s recommendation. 

Is Valley flashing necessary?

Valley flashing may be necessary depending on the type of roof installation and its complexity; check with your local building department concerning specific requirements for your project before proceeding with installation work. 

How wide should a roof valley be?

The width of a roof valley depends on how much room is needed for proper ventilation and run-off but typically, it should be at least 12 inches wide for adequate drainage. 

Following these steps will ensure that your roof installation is secure and leak-proof. If you have any further questions, always consult with a professional before starting any work on your roof. Good luck! 

What is the proper technique for installing shingles in a roof valley to prevent leaks and ensure a secure installation?

To achieve this, follow these essential steps:

1. Begin by preparing the valley area, removing old materials and ensuring the surface is clean and free from debris.
2. Choose the right shingle materials that are durable and suited for valley installations, such as laminated architectural asphalt shingles with fiberglass matting.
3. Apply underlayment, such as felt paper or rollable asphalt-based underlayment, to provide additional waterproofing protection.
4. Install starter shingles along both sides of the valley, ensuring proper alignment for subsequent shingle rows.
5. Lay out shingle courses, overlapping each row by approximately 6 inches to allow water to flow freely off the roof without pooling between courses.
6. Install flashing materials, such as aluminum or copper, around critical points of penetration near valleys to prevent water infiltration.
7. Seal all edges with roofing cement or caulk for added protection against potential leaks.


It’s highly advisable to conduct comprehensive research and enlist the expertise of a qualified professional to handle this crucial aspect of your property’s maintenance.

By taking this approach, you’ll enjoy the long-lasting benefits of a masterfully completed roofing installation.

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