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April 8, 2024

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    One of the most critical parts of your roof is an invisible membrane known as an ice and water shield. An ice and water shield protects your home from moisture, leaks, and water damage.

    Although you can’t see an ice and water shield, it’s a critical component of your roof that can only be installed when getting a roof replacement since it sits under the shingles. This guide runs through what an ice and water shield is, how to install it, and the benefits and disadvantages of having one.

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    • An ice and water shield acts as a protective barrier, protecting vulnerable areas on your roof from water damage and leaks.
    • An ice and water shield should sit on top of the wood sheathing but under the shingles on your roof.
    • These barriers protect your roof from ice and water but can also create a vapor barrier where gasses can’t easily escape.
    • The cost of an ice and water barrier is $4.72 per square foot on average.

    What Is an Ice and Water Shield?

    An ice and water shield, also known as a roofing underlayment, is a waterproof, rubberized underlay installed underneath shingles. It acts as a protective barrier, protecting vulnerable areas on your roof from water damage and leaks.

    This slip-resistant product is a “peel and stick roof underlayment” and self-adheres to the roof deck’s surface, which prevents it from flying up during strong wind.

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    Roofers sometimes install ice and water shields on other vulnerable parts of the roof, such as chimneys, vents, and valleys.

    This video from Digital Roofing Innovations explains why many roofs need ice and water shields:

    How To Install an Ice and Water Protector on a Roof

    Installing an ice and water shield isn’t extremely complicated, but it’s still best to skip DIY for this project and have a professional do it, especially during inclement weather. However, it may be a bit easier to tackle a DIY installation of an ice and water protector as a spot repair or sectional coverage for vulnerable areas vs. the full roof.

    Where To Apply an Ice and Water Shield

    An ice and water shield should sit on top of the wood sheathing but under the shingles on your roof. It should go on top of the fascia board to prevent water penetration and eliminate the gap between the first roof board and the fascia board.

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    Roofing nails are often unnecessary because ice and water shields have self-adhesive backs that create a watertight seal. However, roofing nails and fasteners can hold the material in place until shingles are applied.

    Can You Apply an Ice and Water Shield in the Rain?

    Many ice and water shield makers, like Grace Ice & Water Shield, advise installation during temperatures above 40℉.

    While it’s possible for the temperature to be above 40℉ during rain, working on a wet roof is dangerous, as the rain increases your chances of slipping. Even professional roofers are at risk and have the fifth-highest rate of work-related death in construction, primarily attributed to falls. So, it’s best to wait for relatively warm and dry weather to apply an ice and water shield — or better yet, leave the job to a professional.

    When To Install an Ice and Water Protector

    An ice and water protector should be installed before other underlayments, such as roof felt. If you’re installing roof sheathing around chimneys and dormers, place the ice and water protector below the flashing to create an effective water barrier.

    Watch this video from Cenvar Roofing for a visual tutorial of ice and water shield installation:

    Benefits & Disadvantages of Ice and Water Shield for Roof

    While water shield roofing underlayments provide homeowners with many benefits, they have a few disadvantages. Here is our breakdown of the most common benefits and drawbacks of installing an ice and water shield on your roof:


    • Ice dam and water damage protection for your new roof: An ice and water shield protects your roof from water damage if water seeps past your roof shingles or roof shingles are flung off the roof during a storm, leaving your home exposed.
    • Fairly straightforward installation: Ice and water shields are self-seal products, with one side of the underlayment having a strong adhesive that adheres to the roof deck. This adhesive creates a strong waterproof seal.
    • Added protection for vulnerable areas: Ice and water shields aren’t limited to the roof deck. They can also be installed on vulnerable areas like chimneys, eaves, rake edges, valleys, and overhangs. A contractor will typically assess your roof for areas most prone to damage from ice dams and recommend installing roofing underlayment in these spots for added protection.


    • Creates a vapor barrier: Applying a water shield roofing underlayment to your entire roof results in a vapor barrier where gases build up and can’t easily escape. As a result, you’ll need to consider proper attic ventilation steps and, possibly, a new ventilation system if you decide to cover your entire roof with an ice and water shield.
    • Longer roofing installation process: Installing a roofing underlayment takes time and adds another step and cost to your roof installation. For example, certain areas, like the drip edge, must be installed at the eave before you can adhere it to the roof deck. If you choose to install the ice and water shield yourself, write a detailed list of each step you need to take and what needs to be installed before and after the ice and water shield so you install everything in the correct order.

    Should an Ice and Water Shield be Applied on the Entire Roof?

    Yes and no. An ice and water shield can be applied on the entire roof, but the homeowner should install a ventilation system in the attic to prevent condensation, which can result in water damage.

    If you live in an area with heavy snow or strong winds, an ice and water shield applied to the entire roof may be the added protection you need to prevent leaks, but in many climates, using an ice and water shield for the whole roof is unnecessary.

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    We recommend consulting a professional roofing company for a personalized recommendation based on your location and home.

    What Do Ice and Water Shields Prevent?

    Ice and water shields act as a waterproof barrier that ice, water, and heavy winds can’t lift, preventing water from seeping into your house or the formation of ice dams.

    Wind-driven Rain Damage

    During severe storms, such as tornadoes, hurricanes, or windstorms, strong winds may lift shingles, exposing your roof to the elements. An ice and water shield gives your roof an added layer of protection so that strong gusts can’t lift it. This way, water will continue to push down toward the gutter rather than seeping through the roof or being pushed under shingles by the wind.

    Ice Dams

    Ice dams are heavy ridges of ice that form after melting snow (water) runs off the roof’s edge and freezes, preventing the water from draining off the roof. This often results in more water backing up on the roof, leading to leaks, wrinkles, and water damage to the ceilings, walls, insulation, gutters, and other attic or top-level areas,

    Types of Ice and Water Shields

    There are three primary types of ice and water shields:

    • Smooth surface ice and water shields: These are typically used on low-slope roofs.
    • High-heat ice and water shields: Created from cotton-like fibers, these are typically installed on metal roofs. The material prevents the roof covering from sticking to the metal when it expands and contracts during hot weather, preventing damage to the ice and water shield. For added protection, these are also used on premium roof systems, like cedar shake and slate.
    • Granular or sand surface ice and water shields:  Best installed in roof valleys, these are the thinnest of the three types of ice and water shields. But despite their delicate material, they still have adequate leak protection.

    Read also: Metal Roof Coatings Overview

    How Much Does Ice and Water Shield Cost?

    Ice and water shield costs vary significantly based on the company, location, and kind of ice and water shield you opt for. According to our research, a reputable ice and water shield should cost around $300 for the material, which is an average cost of $4.72 per square foot. The installation cost is typically more, falling between $265 and $280, but this depends on your area.

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    In total, you’re looking at around $550 for a quality ice and water shield, including installation. But prices can range from as low as $385 to higher than $600, depending on the company and material you choose.

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    What Type of Roofing Material Should Be Used With an Ice and Water Shield?

    Ice and water shields work with nearly any type of roofing material, such as asphalt, felt shingles, fiberglass, tile, and metal. Before purchasing an ice and water shield, consult your contractor about the type of roofing underlayment that is best for your roof and home. Certain ice and water shield types suit different materials and climates better.

    Read also: Outstanding Home Warranty Plans for Roofing

    Is an Ice and Water Shield Necessary?

    In many parts of the United States, ice and water shields are necessary and even required by local building codes to protect against ice dams and water damage.

    A common rule of thumb is that if average temperatures in the winter are 25℉ or lower, it’s best to get an ice and water shield to protect against ice dams.

    Is an Ice and Water Shield Worth It?

    In many climates, an ice and water shield is absolutely worth it and even legally required by local building codes. But before making up your mind, consult a professional roofer in your area about the local building regulations and their recommendations for your roof. Depending on your situation, you may only need an ice and water shield on some roof areas which is far less costly (and you might be able to attempt it on your own) than installing it on the entire roof.

    FAQs About Ice and Water Shields

    FAQs About Ice and Water Shields

    Most ice and water shield brands state that their self-adhered underlayments can be exposed for up to 30 days without significant risk of damage.

    Can You Upgrade Your Roof With an Ice and Water Shield?

    Yes, you can upgrade your roof with an ice and water shield to protect your home against heavy snow, rain, and winds. You can also add an ice and water shield around the edges of the roof when replacing your roof to upgrade the level of protection. Most roofing warranties don’t cover ice dams and water damage, so an ice and water shield is an easy upgrade that can help prevent expensive future repairs.

    Can You Apply a Wind and Ice Shield in Hot Weather?

    Yes, you can apply a wind and ice shield in hot weather. Just know that high temperatures can affect roof shingle installation, especially on hot metal roofs. Generally, waiting for mild weather conditions in the spring or fall is best for avoiding extreme temperatures (both hot and cold). If you can’t wait, ask your contractor about high-heat ice and water shields, which can withstand higher temperatures on metal roofs.

    Editorial Contributors
    avatar for Amy DeYoung

    Amy DeYoung


    Amy DeYoung has a passion for educating and motivating homeowners to improve their lives through home improvement projects and preventative measures. She is a content writer and editor specializing in pest control, moving, window, and lawn/gardening content for Today’s Homeowner. Amy utilizes her own experience within the pest control and real estate industry to educate readers. She studied business, communications, and writing at Arizona State University.

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    Lora Novak

    Senior Editor

    Lora Novak meticulously proofreads and edits all commercial content for Today’s Homeowner to guarantee that it contains the most up-to-date information. Lora brings over 12 years of writing, editing, and digital marketing expertise. She’s worked on thousands of articles related to heating, air conditioning, ventilation, roofing, plumbing, lawn/garden, pest control, insurance, and other general homeownership topics.

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