Roof underlayment is a water-resistant or waterproof layer installed directly over the roof deck before metal roofing panels are installed. It adds an essential layer of protection against:

• Water infiltration

• Ice buildup

• Condensation

• Wind-driven rain

• Temperature extremes

For homes in the North Shore, underlayment is crucial for preventing leaks and maximizing the lifespan of your metal roof.

⭐ Types of Underlayment for Metal Roofs

1. Asphalt-Saturated Felt (Traditional Felt Paper)

A classic option and the most budget-friendly.

Pros:

• Cost-effective

• Provides basic water resistance

Cons:

• Prone to wrinkling

• Can degrade faster in humidity

• Less durable for metal roofs in Vancouver’s wet climate

Best for: Smaller projects or temporary protection.

2. Synthetic Underlayment (Most Recommended)

Made from polypropylene or polyethylene, synthetic underlayments are now industry standard for metal roofing.

Pros:

• Lightweight and tear-resistant

• UV-resistant

• Mold and moisture resistant

• Safer installation due to slip-resistant surface

• Ideal for Vancouver’s rain-heavy seasons

Best for: Long-term durability and better performance under metal roofing panels.

3. Self-Adhering Membranes (Ice & Water Shield)

Peel-and-stick underlayment made from rubberized asphalt.

Pros:

• Creates a watertight seal

• Excellent for roof valleys, eaves, and penetrations

• Prevents ice dam-related leaks

• Superior protection against winter conditions

Best for: Areas prone to ice buildup and heavy rainfall—perfect for the North Shore.

4. Rubberized Asphalt Underlayment

A premium, high-performance option that combines asphalt with rubber polymers.

Pros:

• Exceptional waterproofing

• Flexible in extreme temperatures

• Long-lasting

• Excellent for metal roof systems in rainy climates

Best for: Homes that require maximum moisture protection and long-term durability.

⭐ Key Factors When Choosing Underlayment

✔ Climate

Vancouver’s wet, coastal climate requires moisture-resistant, tear-resistant underlayment.
Best options: Synthetic or rubberized asphalt.

✔ Roof Slope

• Steep roofs shed water quickly

• Low-slope roofs benefit from self-adhering membranes for increased protection

✔ Budget

Premium underlayments cost more initially but last longer and reduce the risk of future leaks.

✔ Manufacturer Requirements

Always follow your metal roofing manufacturer’s specifications to maintain warranty coverage and system integrity.

⭐ Why Proper Installation Matters

Even the best underlayment fails if installed incorrectly. Proper installation involves:

• Smooth, wrinkle-free application

• Correct overlap of seams

• Fully sealed edges

• Secure attachment to prevent water intrusion

• Proper integration with flashings and penetrations

At Amex Roofing, our trained installers ensure every metal roof system is protected from the deck up.

⭐ Consult With Amex Roofing: Get the Right Underlayment for Your Metal Roof

Choosing the right underlayment is one of the most important steps in building a durable, weather-resistant metal roof. Whether you're installing a new metal roofing system or upgrading an older one, our team provides expert guidance tailored to your home’s design, climate, and needs.

📍 Serving North Vancouver, West Vancouver, and the entire North Shore
📞 Contact Amex Roofing today to schedule a consultation or request an estimate.

By Amex Roofing