The Role of Underlayment in a Leak-Proof Roof

The Hidden Layer That Protects Your Home from Water Damage

When people think of a roof, they usually picture shingles—but what’s underneath them plays a crucial role in keeping your home dry. That layer is called underlayment, and it’s the last line of defense against leaks if your shingles fail.

Whether you're dealing with storm damage, wind-driven rain, or melting snow, high-quality underlayment can mean the difference between a minor repair and major interior water damage.

🧱 What Is Roofing Underlayment?

Underlayment is a water-resistant or waterproof material installed directly on the roof deck, beneath the shingles. It serves as a protective barrier in case water gets past the top layer.

There are three main types:

• Felt paper (traditional but outdated)

• Synthetic underlayment (lightweight, tear-resistant, long-lasting)

• Ice & water shield (rubberized, self-sealing, ideal for valleys and eaves)

💧 Why It Matters So Much

Shingles are your first defense—but wind, hail, or improper installation can allow water to sneak past. When that happens, underlayment:

• Prevents water from soaking your decking

• Helps control leaks from ice dams or wind-driven rain

• Protects against wood rot, mold, and interior stains

Without it—or with damaged underlayment—your roof becomes vulnerable to long-term moisture problems.

🛠️ Underlayment in Cold Climates

Here in the Quad Cities, ice & water shield is especially important. We install it along:

• Roof valleys

• Eaves and edges

• Around chimneys, skylights, and vents

This creates a watertight seal in the places most prone to snow buildup and ice damming.

🏠 Not Sure What’s Under Your Shingles?

If your roof is more than 15 years old, chances are the underlayment may be outdated—or already failing. At Twin Bridge Roofing and Construction, we inspect, upgrade, and install full roofing systems that protect from the bottom up.

📞 Call (563) 655-4902
🌐 Visit www.roofqc.com to schedule your free inspection

What’s beneath the surface matters—make sure your roof is truly leak-proof.