Synthetic Roof Underlayment

Roof underlayment is one of the hidden components of a roofing system, but it plays an important role in protecting your home. It is installed over the roof deck after the ice and water shield has been applied and before the shingles are installed.

Its primary purpose is to provide a secondary layer of protection if water gets beneath the shingles due to wind-driven rain or severe weather. It also helps protect the roof deck from moisture exposure during the roofing installation if weather conditions change before the shingles are installed.

While homeowners rarely see it after the roof is completed, underlayment is an important part of a complete roofing system and helps improve the overall performance and longevity of the roof.

Types of Roof Underlayment

Several types of roof underlayment are available, each designed to provide a protective layer between the roof deck and the shingles.

Asphalt felt, often called tar paper or felt paper, has been used for decades and is still installed on some roofing projects. It is available in different weights and provides a basic layer of water resistance beneath the shingles.

Synthetic underlayment is manufactured from engineered materials designed to provide improved strength, durability, and moisture resistance. It is lighter than felt, more resistant to tearing, and less likely to wrinkle during installation. It also provides better temporary weather protection if the roofing project is delayed due to changing weather conditions.

While both products serve the same purpose, synthetic underlayment has become the preferred choice for many roofing contractors because of its improved performance and durability.

The type of underlayment selected depends on the roofing system, manufacturer requirements, roof design, budget, and contractor recommendations.

Typical Cost

Roof underlayment is typically included as part of a complete roof replacement and is not usually priced as a separate item.

Synthetic underlayment generally costs more than traditional felt paper, but it represents a relatively small portion of the total roofing investment while providing improved durability and long-term protection.

Benefits

• Provides a secondary water-resistant barrier

• Protects the roof deck from moisture

• Helps protect the home during roof installation

• More tear resistant than traditional felt

• Less likely to wrinkle

• Better moisture resistance

• Improves the overall performance of the roofing system

• Supports long-term roof durability

Why It Matters in Michigan

Michigan roofs are exposed to heavy rain, snow, strong winds, and repeated freeze-thaw cycles throughout the year. These changing weather conditions make every layer of the roofing system important.

Roof underlayment helps provide an additional layer of protection beneath the shingles while helping safeguard the roof deck from moisture. Combined with ice and water shield, flashing, proper ventilation, and quality shingles, it contributes to a roofing system designed to perform in Michigan's demanding climate.

Our Recommendation

At VanderLaans, we recommend high-quality synthetic roof underlayment for most residential roof replacements because of its strength, durability, and long-term performance.

Every roof is different, and the type of underlayment used should meet the roofing manufacturer's requirements and be appropriate for the specific project. While homeowners never see it after the roof is completed, underlayment is one of the most important layers protecting your home beneath the shingles.

Did You Know?

Many homeowners think shingles are the only thing protecting their roof from water. In reality, a quality roofing system consists of multiple layers working together. If water gets beneath the shingles during severe weather, the roof underlayment provides an important second line of defense that helps protect the roof deck and the interior of your home.