What Is An Ice and Water Shield?

Posted on September 25, 2024

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What Is An Ice and Water Shield

Having a sturdy and long-lasting roof is essential for protecting your home against the weather. Nonetheless, particularly in areas susceptible to significant snowfall, ice, or wind-driven rain, even the best-built roofs may sustain water damage. 

As a vital line of defense against water infiltration and subsequent structural damage, ice and water shields are a necessary part of a roofing system. We will examine the definition, application procedure, advantages, and other details of ice and water shields in this blog post.

What Is An Ice And Water Shield And Why Is It Important?

An ice and water shield is a self-adhesive, waterproof layer used in roofing to protect against water damage, especially in areas prone to ice dams or heavy rain. Made from rubberized asphalt or modified bitumen, it forms a tight seal, stopping leaks that can cause major structural issues. 

Installed directly on the roof deck before the roof shingles, it offers extra protection in vulnerable areas like eaves, valleys, and around chimneys. This shield not only helps extend the roof’s lifespan but also meets building codes in colder climates, making it essential for safeguarding homes during harsh weather. 

Here’s everything you need to know about ice and water shields:

  • Waterproof Protection: Ice and water shields create a waterproof layer on the roof deck to prevent leaks and water damage.
  • Ice Dam Prevention: These shields protect areas like eaves and valleys from ice dams.
  • Self-Sealing Properties: The membrane seals around nails during installation, reducing the chance of leaks even in harsh weather.
  • Building Code Compliance: Many regions with heavy snow require an ice and water shield to meet building codes and boost roof durability.
Ice And Water Shield

Where Does An Ice And Water Shield Go On A Roof?

The shield is installed in the most leak-prone areas of the roof, providing added protection in key spots such as:

1. Eaves

Installed at the roof’s edge, extending 24 inches inside the exterior wall, typically covering at least two rows (or six feet). This prevents ice dams from causing leaks.

2. Roof Valleys

Valleys, where two roof sections meet, direct more water flow, so a single row (three feet wide) is installed.

3. Roof Penetrations

Areas around pipes, exhaust fans, chimneys, skylights, and other objects that pass through the roof get shielded for added protection.

5. Rake Edges and Overhangs

 Vulnerable to ice dams and wind-driven rain, these areas are covered to stop potential leaks.

6. Entire Low-Slope Roofs

Ice and water shields are particularly crucial for roofs with pitches between 2:12 and 4:12, where snow and water tend to accumulate, increasing the risk of water seepage.

Types of Ice and Water Shield

There are different types of ice and water shields, each tailored for specific roofing needs:

1. High Heat Ice and Water Shield

Designed for metal roofs and premium systems like cedar shake and slate, this type features cotton-like fibers to prevent it from sticking to the roofing material in high temperatures.

2. Smooth Surface Ice and Water Shield

Best for low-slope roofs, it provides strong leak protection while maintaining a smooth surface.

3. Granular or Sand Surface Ice and Water Shield

The thinnest option, ideal for roof valleys where extra protection is needed against water accumulation.

Ice and Water Shield vs. Roof Underlayment: What Is The Difference?

Many homeowners often wonder whether ice and water shields and roof underlayment are the same or if they serve different purposes. Understanding their differences can help you choose the right protection for your roof.

FEATURE ICE AND WATER SHIELD UNDERLAYMENT
PurposeProtects vulnerable areas from water damageProvides general moisture protection across the roof deck
Moisture BarrierMoisture-tight barrierWater-resistant but not moisture-tight
Installation MethodSelf-adhesive, bonds directly to the roof deckSecured with staples or nails
Areas of ApplicationCritical areas (eaves, valleys, penetrations)Entire roof deck
Protection Against Ice DamsYes, specifically designed for this purposeNo, does not provide targeted protection against ice dams
Material TypesTypically a rubberized asphalt membraneFelt paper or synthetic materials
DurabilityHighly durable, designed for long-term useVaries, but synthetic options are generally more durable than felt
CostGenerally more expensive due to specialized functionTypically less expensive than ice and water shields

How To Install Ice And Water Shield

An ice and water shield is installed early in the roofing process, adhering directly to the roof deck. Here is a general overview of the installation: 

Preparation for Installation

Before starting, gather these materials:

  • Ice and water shield rolls
  • Utility knife
  • Measuring tape
  • Chalk line
  • Roofing nails (if needed)

Conditions for Installation

Install the ice and water shield when temperatures are above 40 degrees for best adhesion. Avoid installing it in wet conditions, as moisture can affect how well it sticks.

Step-by-Step Installation Process

1. Prepare the Roof Deck

Start by ensuring the roof deck is clean, dry, and free of debris. Remove any old roofing materials if needed.

2. Install Drip Edge

Place a drip edge along the eaves before applying the ice and water shield to help direct water away from the roof edges.

3. Measure and Cut the Ice and Water Shield

Measure the required length for each section. Cut pieces to extend 24 inches up from the eaves and longer for valleys or transitions if needed.

4. Apply the Ice and Water Shield

Unroll the shield starting from one edge of the roof, keeping the release liner intact. Align it according to your measurements, ensuring overlaps of at least 6 inches. Peel back the release liner gradually and press the shield onto the roof deck.

5. Secure with Fasteners (if needed)

Although the shield is self-adhering, some manufacturers recommend using temporary fasteners (like roofing nails) to hold it in place until shingles are applied. Space these fasteners at least 12 inches apart along the edges.

6. Overlap Sections

When installing multiple courses, overlap each new course by at least 6 inches horizontally and 12 inches vertically.

7. Trim Excess Material

After installation, use a utility knife to trim excess material for a clean finish around edges and roof penetrations like vents or chimneys.

8. Inspect for Gaps

Check for any gaps where water could enter.

9. Install Shingles

Proceed with the rest of the installation over the ice and water shield, following manufacturer instructions.

By following these steps, you can ensure your roof is water-tight for years to come. 

Conclusion

Investing in an ice and water shield is a smart choice for your home’s roof. It guards against leaks and extends your roof’s lifespan by protecting it from severe weather. If you’re thinking about installing one or need help with your roofing project, a professional roofer can provide expert advice tailored to your needs.

As a leading roofing expert, OConnor Contracting offers exceptional roofing services to keep your home safe and dry. We specialize in installing ice and water shields, ensuring your roof is protected from leaks and severe weather. For expert advice and reliable roofing solutions, reach out to us today at (716) 600-7663.

FAQs

A.Building codes may require ice and water shields in areas prone to ice dams. For instance, in New York, certain counties mandate their use on roofs to prevent leaks from ice buildup. The shield must often extend beyond the interior wall line and cover vulnerable areas like eaves and valleys. Requirements can vary by location, so it’s crucial to check local building codes for compliance.

A. When installed correctly beneath roofing materials, an ice and water shield offers durable protection against water infiltration for 20 to 50 years. Its design effectively prevents leaks from ice dams and heavy rain. Many manufacturers also provide limited lifetime warranties, highlighting the material’s long-lasting reliability and resilience when properly maintained and covered.

A. No, an ice and water shield should not be installed over old roofing. For maximum effectiveness, it needs to be applied directly onto the clean, dry roof deck. This ensures it can properly adhere and create a strong waterproof barrier. Therefore, it’s best to install it during roof replacement or new construction.

What Is An Ice and Water Shield
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