When it comes to metal roofing, underlayment is an essential component that ensures long-lasting protection for your home. Underlayments act as a barrier between your roof deck (usually made from OSB or plywood) and the metal roofing material, helping to prevent moisture intrusion and protect against the elements.

Metal roofs are unique in their ability to handle extreme weather and temperature variations. This makes selecting the correct underlayment critical to the overall success of your roof installation. In this guide, we’ll walk you through key considerations and outline some top-performing underlayments from GAF, Owens Corning, and CertainTeed.

Key Considerations for Metal Roof Underlayments

Because metal roofs tend to generate more heat, it’s important to choose an underlayment that can withstand high temperatures. Additionally, the underlayment should be compatible with the metal roof’s installation system. Before selecting an underlayment, consider the following:

• Does the underlayment provide adequate moisture protection?
• What is the climate and weather condition in your area?
• Are there local building codes you need to follow?
• What slope does your roof have?

Answering these questions will help guide your decision toward the best underlayment for your project.

Underlayment Types for Metal Roofs

There are two main types of underlayments that work well with metal roofs:

1. Self-Adhered Underlayment

Self-adhered underlayments (also known as ice and water barriers) offer exceptional waterproofing by sealing tightly to the roof deck. They are especially useful in areas prone to heavy rain, snow, or ice dams, and can be applied across the entire roof or in vulnerable areas like valleys and eaves.

At 1-256-ROOFERS, we recommend self-adhered underlayments for added protection under your metal roof. Here are a few top options:

GAF Underlayment Options:

• GAF WeatherWatch® – Designed for superior protection against leaks and ice dams, this underlayment offers high-temperature resistance and excellent adhesion.
• GAF StormGuard® – A strong choice for preventing moisture infiltration, especially in areas that experience frequent storms or extreme weather conditions.

Owens Corning Underlayment Options:

• WeatherLock® Specialty Tile & Metal – Specifically designed for metal roofs, this underlayment provides a watertight seal and protects against leaks and ice dams.
• Titanium® PSU30 – A premium, high-performance self-adhered underlayment offering superior protection and durability for metal roofing systems.

CertainTeed Underlayment Options:

• CertainTeed WinterGuard® – Known for its durability and resistance to water, ice, and wind-driven rain, this underlayment is an excellent choice for metal roof installations.

2. Synthetic Underlayment

Synthetic underlayments are crafted from strong, durable fibers, offering superior tear resistance and longevity compared to traditional felt. These underlayments are water-repellent, lightweight, and often include non-skid surfaces for safer installation. Synthetics can also endure UV exposure for extended periods, making them ideal for metal roofing projects.

GAF Synthetic Underlayment Options:

• GAF Tiger Paw™ – This premium synthetic underlayment is highly durable, tear-resistant, and designed to provide enhanced protection for metal roofs.
• GAF Deck-Armor™ – Offers breathability while still providing a water-resistant barrier, ensuring a longer-lasting roof system.

Owens Corning Synthetic Underlayment Options:

• Titanium® UDL25 – A lightweight, durable synthetic underlayment that can withstand up to 6 months of UV exposure and provides superior water shedding.
• Titanium® UDL50 – A high-performance underlayment designed for maximum durability and long-term performance under metal roofs.

CertainTeed Synthetic Underlayment Options:

• DiamondDeck® – A premium synthetic underlayment offering superior strength, water resistance, and ease of installation under metal roofs.

Why Choose Synthetic Over Felt?

In the past, felt was commonly used for roof underlayment, but synthetic options have become more popular for good reasons:

• Stronger and more durable
• Higher resistance to tearing
• Lighter and easier to install
• Better water resistance
• Longer UV resistance

While felt is still available, we highly recommend choosing synthetic underlayments for metal roofing due to their improved performance and longevity.