Starter Shingles and Their Purpose

When most people think about roofing, they picture the visible shingles that cover the majority of the roof. 

However, a properly installed roof depends on several less noticeable components working together behind the scenes. One of the most important of these components is the starter shingle.

In this article, you’ll learn what starter shingles are, what their purpose is, and how they contribute to the overall performance of your roof.

What are starter shingles?

Starter shingles are the first row of shingles installed on a roof, placed along the eaves (bottom edges) and rake edges (sloped sides). They’re installed immediately after the underlayment and drip edge, and just before the first layer of visible shingles.

Like regular shingles, starter shingles are flat, rectangular, and reinforced with fiberglass and granules. Since they’re not designed to be seen, starter shingles are usually a dark color that has nothing to do with the color scheme on the rest of the building. 

Starter shingles serve as a foundation for the first layer of regular shingles. They come with an adhesive strip that faces upward. The first layer of finish shingles bonds directly to this adhesive, which locks them into place. This effectively seals the roof edges against water, and prevents the wind from lifting shingle corners. It also provides a clean, straight edge that helps ensure the rest of the shingles are properly aligned.

Types of starter shingles

There are two types of starter shingles:

• Pre-manufactured starter shingles, specifically designed to be used as such
• Three-tab shingles, modified to be used as starters

Some shingles are specifically manufactured to be used as starters. They’re flat, consistently sized, and include correctly placed adhesive strips. If you can afford them, these are the best option. They’re easy to install and will create a clean, uniform roof edge that meets professional standards. The only downside is that they’re rather expensive.

Traditional three-tab shingles can be adapted as starter shingles by cutting off the tabs, leaving a straight strip with the adhesive positioned at the bottom edge. This method can work when done correctly, and it’s often cheaper, since regular three-tab shingles are more readily available than starter ones. They’re more labor-intensive to create and install, however, and may result in uneven edges if not installed correctly. 

What is the purpose of starter shingles?

Without starter shingles, your roof would be far more vulnerable to damage. You could expect leaks, shingles blowing off in storms, and damage to the roof deck. All this would reduce the lifespan of your roof significantly. 

Starter shingles serve several vital functions that reduce the chances of this type of damage. Here are some of the most important ones. 

Waterproofing

Roof edges are especially vulnerable to water intrusion. 

Starter shingles seal gaps beneath the first row of shingles, preventing water from seeping under the roof covering and damaging the roof deck, fascia, or interior structure.

It’s worth noting that regular shingles alone could not provide this level of waterproofing at your roof’s edge. 

Wind protection

One of the most common causes of roof damage is when the wind gets underneath your shingles and blows them off in a storm.

Starter shingles reduce the odds of this happening, since their adhesive strip locks down the first row of shingles at the edge of your roof. 

Aesthetics

Starter shingles establish a straight, consistent reference line along the roof edge. 

This ensures that all subsequent shingle layers align properly, resulting in a clean, professional-looking roof, as opposed to uneven or jagged shingle lines.

Warranty Protection

Most roofs come with two warranties: one for the materials, and the other for the workmanship.

In the vast majority of cases, you’ll need properly installed starter shingles to ensure that both warranties are valid. 

This makes sense from a practical perspective, as it would be foolish to offer a warranty on a roof that’s likely to be damaged by the first mild storm it experiences. 

How Starter Shingles Are Installed

The installation process for starter shingles varies from manufacturer to manufacturer. But two important caveats before we get started:

That being said, here are some general principles to follow during installation.

1. Install along all eaves and rake edges

As mentioned earlier, your starter shingles are your best line of defence against the elements, and your roof’s edge is where it’s most vulnerable. 

So make sure you install starters along the edges of the entire roof, so as to create a watertight seal that locks the other shingles into place. 

2. Allow a slight overhang beyond the roof edge

Starter shingles typically extend ¼ inch to ¾ inch beyond the drip edge. It can even be up to 1 inch, depending on the manufacturer guidelines. 

The overhang ensures that rainwater flows off the shingles and drip edge, as opposed to running back under the shingles or onto the fascia. Without the overhang, water could seep under the shingles and cause rot or leaks.

3. Align the adhesive strip correctly

Make sure the adhesive strip is facing upward, ready to bond with the first row of regular shingles.

The bottom of the starter shingle should line up evenly with the roof’s drip edge. This ensures the adhesive strip will sit directly under the first layer of shingles, without any gaps.

Once aligned, press the starter shingle down to activate the adhesive strip. Some shingles are self-sealing and bond over time using heat from the sun, but initial firm placement ensures proper contact.

4. Nail according to manufacturer guidelines

Starter shingles don’t usually have a clearly marked nail line. However, most manufacturers specify that:

• Nails should be placed 3-4 inches from the exterior edge
• Fasteners should be placed approximately 1 inch from each end, with additional nails spaced evenly
• Nails should avoid interference with the adhesive strip
• Exposed nails should be avoided to ensure proper sealing

Starter shingle FAQs

Is a starter shingle the same thing as an upside-down shingle?

No. Installing a three-tab shingle upside down places the adhesive in the wrong location and fails to seal the first layer of shingles. If three-tab shingles are used, the tabs must be trimmed off so the adhesive sits at the roof edge.

Do starter shingles need sealant?

In most cases, the adhesive strip plus the nails are enough. However, you might consider adding extra sealant if you live in an area with lots of wind or freezing temperatures. Sometimes, a bit of roofing cement is used as a sealant. 

Are starter shingles necessary for architectural shingles?

Absolutely. Starter shingles are especially important for architectural shingles shingles, as these heavier shingles rely on a secure sealed edge for proper wind resistance and performance.

Wrapping up

If you’re installing a new roof with shingles on, your roof needs starter shingles to be resistant enough to the elements to keep your family safe. 

Installing starter shingles is hard work. But fortunately, there’s no need to do it alone. Call Presidio on (210) 660-3682 today, and we’ll take care of it for you!