When you think about your roof, you probably picture shingles, tiles, or metal panels.
But underneath that outer layer is a hidden, crucial component—roofing underlayment.
This waterproof or water-resistant barrier is what truly protects your home from leaks, moisture damage, and even extreme weather conditions.
At Roofers Worcester, we educate homeowners on the importance of a well-installed and high-quality underlayment.
In this guide, I’ll break down what roofing underlayment is, why it’s essential, and how to choose the right type for your home.
1. What Is Roofing Underlayment?
Roofing underlayment is a protective layer installed between your roof deck (the wooden base) and your outer roofing material (shingles, tiles, or metal panels). It serves as an extra shield against water, wind, and temperature fluctuations.
Why Is Underlayment Important?
✅ Prevents leaks by acting as a second line of defense.
✅ Improves roof durability by protecting against moisture buildup.
✅ Increases energy efficiency by helping regulate attic temperature.
✅ Meets building codes—most regions require underlayment beneath roofing materials.
✔ Tip: Even if your shingles or tiles are intact, a damaged or missing underlayment can lead to serious leaks and structural issues.
2. Types of Roofing Underlayment
Not all underlayments are the same. The best choice depends on your climate, roof type, and budget.
A. Asphalt-Saturated Felt (Traditional Felt Paper)
Also known as tar paper, this is the oldest and most common underlayment type.
✅ Pros:
✔ Affordable and widely available.
✔ Provides a basic moisture barrier.
✔ Available in 15-pound and 30-pound thicknesses (30-pound is more durable).
❌ Cons:
❌ Less resistant to tearing and UV exposure.
❌ Can absorb water, leading to deterioration over time.
✔ Best For: Homeowners on a budget who need basic protection.
B. Synthetic Underlayment (High-Performance Option)
Made from woven polymers and plastic materials, synthetic underlayment is stronger, lighter, and more durable than felt.
✅ Pros:
✔ Highly resistant to tears, mold, and UV exposure.
✔ Lighter and easier to install than felt.
✔ Provides better water resistance.
✔ More slip-resistant, improving roofing worker safety.
❌ Cons:
❌ More expensive than traditional felt.
❌ Some low-quality synthetics may not meet strict building codes.
✔ Best For: Homeowners looking for superior durability and long-lasting protection.
C. Rubberized Asphalt Underlayment (Best for Extreme Weather)
A premium waterproof underlayment made with rubber polymers and asphalt for maximum protection against water and ice.
✅ Pros:
✔ Completely waterproof (not just water-resistant).
✔ Best for cold climates and heavy rain areas.
✔ Self-adhering, creating a tight seal around nails and fasteners.
❌ Cons:
❌ The most expensive underlayment option.
❌ Heavier and harder to install compared to synthetic materials.
✔ Best For: Homes in storm-prone or cold climates, where ice dams and heavy rain are common.
3. How Roofing Underlayment Protects Your Home
A. Prevents Water Damage & Leaks
Underlayment creates a waterproof barrier, ensuring that even if shingles blow off, water doesn’t seep into your home.
🚨 Without underlayment, water can:
❌ Soak into the wooden roof deck, causing rot and mold.
❌ Leak into ceilings and walls, leading to expensive repairs.
❌ Reduce insulation effectiveness, raising energy bills.
✔ Tip: If you live in an area with heavy rainfall, a high-quality underlayment is a must.
B. Protects Against Ice Dams & Wind-Driven Rain
Ice dams form when snow melts and refreezes at the roof’s edge, trapping water underneath. A waterproof underlayment stops this water from seeping into your home.
🚨 Wind-driven rain can:
❌ Blow under shingles and soak into the roof deck.
❌ Cause leaks even if the roofing material looks fine.
✔ Tip: If your home is in a cold or hurricane-prone area, choose a rubberized asphalt underlayment for the best protection.
C. Adds an Extra Layer of Insulation
Underlayment helps regulate temperature and moisture levels inside your attic.
✅ Reduces heat buildup in summer.
✅ Prevents condensation and mold growth in winter.
✅ Helps keep your home energy-efficient.
✔ Tip: If your attic gets too hot or humid, check whether your roofing underlayment and ventilation are working properly.
4. Underlayment Installation & Maintenance
A. When Should Underlayment Be Replaced?
If you’re getting a new roof, the underlayment should always be replaced along with the shingles.
🚨 Signs Your Underlayment Needs Replacement:
❌ Your roof is 15+ years old and showing wear.
❌ You notice water stains or mold in the attic.
❌ Your shingles are curling, missing, or damaged.
✔ Tip: If you’re not sure about your underlayment’s condition, a professional roof inspection can check for hidden damage.
5. The Cost of Roofing Underlayment
Underlayment costs depend on the material type and roof size.
✔ Tip: A higher-quality underlayment can extend your roof’s lifespan and reduce future repair costs.
To Sum Up: Why Roofing Underlayment Matters
✔ Protects your home from leaks, mold, and water damage.
✔ Adds an extra insulation layer, improving energy efficiency.
✔ Extends your roof’s lifespan by preventing moisture buildup.
✔ Different types offer different levels of protection—choose based on climate and roof type.
At Roofers Worcester, we use top-quality underlayment materials to ensure long-lasting roof protection.
Contact us today for a professional roof inspection and expert recommendations!
FAQs
Do all roofs need underlayment?
Yes! Underlayment is a critical part of any roofing system, no matter the material.
Can I install a new roof without replacing the underlayment?
No—old underlayment should always be replaced when installing new shingles.
How long does roof underlayment last?
It depends on the type—felt lasts 10-15 years, while synthetic or rubberized asphalt can last 20-50 years.
🚨 Need a roof replacement? Call Roofers Worcester today for expert advice on the best underlayment for your home! 🚨