Do You Put Underlayment Over An Ice And Water Shield?

Posted on October 30, 2023

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Do You Put Underlayment Over An Ice And Water Shield?

Roofs are designed to protect homes from the elements, but they can only do so effectively if they’re properly installed. One crucial aspect of roof installation is ensuring that there are barriers to prevent water and ice damage, which is where ice and water shields come into play. Another critical layer is the underlayment, which provides additional protection and stability. But how do these two components work together, and in what order should they be installed? In this blog post, we’ll answer the question as to if you put underlayment over an ice and water shield. 

What Is Roof Underlayment?

Do You Put Underlayment Over Ice And Water Shield - New Jersey Roofing Contractor
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Underlayment is a vital component of any roofing system. It serves as a secondary barrier against moisture, helping to protect your roof and home from the elements. 

Commonly made of asphalt-saturated felt or synthetic materials, underlayment is installed over the entire roof deck, just beneath the shingles. It provides a smooth surface for the shingles to lay on, and acts as an extra layer of protection 

Ice and Water Shield: A Waterproof Barrier

Do You Put Underlayment Over Ice And Water Shield - New Jersey Roofing Contractor
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The ice and water shield, on the other hand, is a rubberized asphalt membrane with a self-adhesive backing, designed to provide a watertight seal in areas prone to ice and water infiltration. While the purpose of installing underlayment and an ice and water shield is the same, an ice and water shield is different from traditional roofing felt (asphalt-saturated felt), due to its superior waterproofing capabilities. This material is installed in specific regions of the roof, such as eaves, valleys, and around roof penetrations. 

The primary purpose of the ice and water shield is to prevent water intrusion caused by ice dams, wind-driven rain, and other severe weather conditions.

Also, Read – Will Shingles Stick To Old Ice And Water Shield? 

Can You Install Underlayment Over An Ice and Water Shield?

The key to a leak-free and durable roof lies in the correct order of installation of these protective layers. According to experts, the ice and water shield should be installed first, directly onto a roof deck that is clean and dry. You don’t have to apply it to the entire roof deck unless your building code requires it. Just ensure that vulnerable areas, such as chimneys and dormers, are protected. 

The underlayment, such as felt paper, should then be installed over the ice and water shield, covering the rest of the roof deck before the shingles are laid down. This order ensures that the roof deck has another, more durable protective membrane if the underlayment is to fail.

The Proper Sequence of Installing Underlayment Over An Ice and Water Shield

This is the right sequence to follow for installing roof underlayment over an ice and water shield. 

1. Roof Deck Preparation

Start with a clean and well-prepared roof deck. Ensure it’s free of any debris, protruding nails, or damaged areas.

2. Ice and Water Shield Installation

Apply the ice and water shield in the areas where it’s needed the most – typically around dormers, chimneys, roof valleys, and roof penetrations. Ensure proper sealing and overlap to create a watertight barrier.

3. Roof Underlayment

Once the ice and water shield is in place, you can proceed with the installation of the underlayment. Lay the underlayment perpendicular to the eaves of the roof and overlap as per the manufacturer’s guidelines.

4. Roofing Material Application

After installing the ice and water shield, and underlayment correctly, apply your chosen roofing material, whether it’s shingles, metal, or tile. Ensure proper fastening and sealing around the joints and eaves. 

Contact Northkit Roofing In New Jersey For Your Roof Installation or Replacement 

If you are considering installing or replacing your roof in New Jersey, contact Northkit Roofing, your local roofing company. Our team has years of experience providing roofing and home exterior services in New Jersey, and want to help you! Whether you need a complete roof replacement or just a minor repair, we’re able to handle whatever you need. Give us a call today at (973)-396-7416 and consult with one of our roofing professionals.

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