Most homeowners think shingles are what keep water out. They’re not.

Shingles are the first defense. The real waterproofing layer protecting your home is roof underlayment.

Roof underlayment is installed directly on top of the roof decking before shingles are installed. It creates a secondary water barrier in case wind-driven rain gets past the shingles. In hurricane-prone areas like Florida, this hidden layer is one of the most important parts of the entire roofing system.

Why Roof Underlayment Exists

Your roof constantly faces wind, rain, UV exposure, and thousands of nail penetrations. Shingles are designed to shed water, not seal it. Underlayment seals the roof deck and prevents moisture from entering your home if shingles are damaged or blown off during storms.

Think of shingles as armor and underlayment as the waterproof skin underneath.

Types of Underlayment

Felt Paper (Traditional)

Affordable but tears easily and absorbs moisture.

Synthetic Underlayment

Stronger, lighter, and more resistant to tearing and wind.

Peel & Stick Underlayment (Premium)

Self-sealing, fully waterproof, and ideal for hurricane regions.

Why Underlayment Matters in Florida

Florida roofs face hurricane winds, heavy rainfall, and intense sun exposure. If shingles blow off during a storm, underlayment becomes the last line of defense protecting the interior of your home.

Signs of Underlayment Failure

• Ceiling stains

• Attic moisture or mold

• Leaks after storms

• Wood rot in decking

Most roof leaks begin when underlayment fails.

Bottom Line

You may never see underlayment, but it may be the most important layer of your roof. If you’re replacing your roof, this is not the place to cut corners.