Ice & Water Shield: Why Is It Important? How Does It Work?

RSG Roofing, LLC

Mar 84 min read

Your roof is one of the most important parts of your home, keeping you and all of your valuables safe from the elements. Without a properly installed roof on your home, you may as not even have one at all. It’s important to install your roof right the first time, that’s why making sure your roof is installed to top standards is an absolute MUST. One of the most important layers on your roof is the first layer after the decking, the leak barrier or ice and water shield. Many states require the installation of ice and water shield in some areas if the roof on roof installations. Ice and water shield helps protect against leaks, rot and mold and protects the structural integrity of your home.

Ice and water shield is the first barrier protecting your home against leaks caused by:

Ice dams
Wind-driven rain
Heavy snow buildup

A leak barrier is crucial for homes in colder climates that are subject to these potential leak hazards. The most effective installation of Ice and water shield is when it’s installed in critical areas like eaves, valleys, and around roof penetrations such as chimneys, vents, and other exposed areas on the roof.

Protecting the Eaves from Ice Dams & Wind-Driven Rain

Ice Dams:

The eaves, or edges of the roof, are particularly important when it comes to protection, especially when it comes to ice dams. When snow melts on the roof, due to sun exposure and heat escaping from the interior of the home, often times melting snow re-freezes again on the eaves. The eaves tend to be colder which in turn causes ice damming making it critical for ice and water shield to be installed thoroughly in this area. When installed on the eaves, ice and water shield prevents water from backing up behind ice dams, seeping under the shingles and leaking into the home. Installation in this area protects the roof decking from rot and keep water from destroying the interior of the home.

Wind-Driven Rain:

Wind-driven rains can also cause leak issues on the eaves, especially if the area has lifted shingles. Wind forces are higher during storms at the eaves, hip & ridges often causing shingles to lift.

Shingle lifting can occur for a variety of reasons stated below:

Improper Shingle Installation - Instances with improper nailing, misalignment or insufficient overlap can make shingles more susceptible to lifting during a storm
Roof Aging and Deterioration –Roof aging causes shingles to become brittle and causes them to lose their flexibility often causing lifting with high winds.
Poor Attic Ventilation – Improper ventilation can cause heat and water to build up on the decking causing the shingles to age faster and lift.
Harsh Weather Conditions – Extreme weather can also cause lifting due to expedited aging of the shingles from the elements.
Manufacturing Defects – Occasionally a manufacture defect can cause shingles to lift prematurely.

When wind blows up these shingles in these vulnerable areas it leaves the layers below exposed to moisture, Ice and water is absolutely necessary in the eaves to protect from an incident such as this.

Protecting the Valleys form Ice Dams & Heavy Snow Buildup

The valleys of the roof, where two slopes meet, are just as important when it comes to preventing water from entering the home. Valleys are particularly vulnerable to ice damming because they collect a high concentration of melting snow and rainwater as water flows down both slopes from the larger areas above. Ice damming often occurs in this area from snow piling up between the two slopes. When snow accumulates in this area it prevents proper drainage of melting snow from the area, in turn causing a potential risk for water entering the home through the exposed area. Due to this buildup that occurs during the winter months it is essential to install ice and water in this area as well.

Example of ice damming in the valley on a roof. — Example of ice damming in the valley of the roof.

Protecting Other Exposed Areas and Penetrations

It is important to also take other open exposed areas on the roof into consideration for protection. Areas such as; chimneys, skylights, exhaust vents, pipes, hips, ridges and rakes are all points of exposure and pose a risk for water entering the home. Wind-driven rain plays a factor in exposing these areas, as discussed above. If these areas are not properly sealed water will find its way into the cracks and leak into your home. It is important to always consider these areas during an install. Ice and water shield in these areas is one more step to assuring your home stays dry and protected.

As much as ice and water shield can be a saving grace, if not installed correctly the product well fail and leave a homeowner with leaks and headaches. When installing ice and water shield, the adhesive layers on the product, must overlap to ensure a water tight seal preventing water from penetrating between. Ice and water shield, installed correctly, creates a better seal around nails in the decking compared to a traditional underlayment such as felt paper. With the installation of ice and water shield it creates a barrier protecting the integrity of the roof even if water does happen to make it under the shingles. Protecting the different aspects of your roof can extend the life of your roof for years to come. Having your home protected from the outside threats from weather can help ease your mind and save more time for investing that energy elsewhere.

Let’s re-cap the benefits of ice and water shield:

Prevents Leaks
Protects Roof Decking
Extends Roof Life Span
Peace of Mind

While installation of ice and water shield doesn’t necessarily need to be installed on the entire roof, here at RSG Roofing we install every roof to these standards even when code does not require such an extensive installation. As an added precaution we install a double row of ice and water shield on eaves larger than 12” to assure adequate coverage into the interior warm walls. We want every home sealed tight from the start, taking every step to make sure we provide a top quality roof replacement on every job protecting your home for years to come.