When it comes to roofing, shingles often steal the spotlight. But beneath every reliable and long-lasting roof lies an unsung hero: the underlayment. This hidden layer plays a crucial role in protecting your home from water infiltration, weather damage, and structural decay.
Let’s explore what underlayment is, why it matters, and how to choose the right type for your roofing project.
🧱 What Is Roofing Underlayment?
Roofing underlayment is a protective barrier installed directly on top of the roof deck and beneath the shingles. It acts as a secondary moisture barrier, shielding your home if shingles are damaged, displaced, or improperly sealed.
There are three main types of underlayment:
| Type | Description |
|---|---|
| Asphalt-Saturated Felt | Traditional option (15- or 30-pound), water-resistant, cost-effective |
| Synthetic Underlayment | Made of polypropylene or polyester, lightweight, tear-resistant, and highly durable |
| Rubberized Asphalt | Self-adhering, waterproof, ideal for high-risk areas like valleys and eaves |
🛡 Why Underlayment Is Essential
1. Moisture Protection
Shingles are your first defense—but not your only one. Underlayment prevents water from seeping into the roof deck during:
Heavy rains
Ice damming
Wind-driven storms
Even the smallest leak in a shingle can cause rot, mold, and insulation damage without underlayment.
2. Wind & Storm Resistance
High winds can lift shingles or drive rain underneath them. Underlayment serves as a fail-safe layer that protects the deck from direct exposure to the elements.
3. Improved Fire Ratings
Many building codes require underlayment to meet Class A fire rating standards—particularly in fire-prone areas. The right underlayment enhances your roof’s overall fire resistance.
4. Even Surface for Shingle Installation
Underlayment creates a smoother, uniform surface over the decking, ensuring better shingle alignment and sealing, especially on older or slightly uneven decks.
5. Code Compliance & Manufacturer Warranties
Most local building codes and roofing manufacturers mandate underlayment as part of their approved installation process. Skipping it could:
Void your shingle warranty
Lead to building code violations
Compromise insurance claims
🧰 Choosing the Right Underlayment
✅ Climate Considerations
In humid or wet regions, synthetic or rubberized asphalt underlayments offer superior water resistance.
In hot climates, look for UV-resistant synthetic options if your shingles won’t be installed immediately.
✅ Roof Pitch
Low-slope roofs (under 4:12) are more prone to water pooling and may require self-adhesive waterproof membranes.
Steeper roofs are generally well-served by synthetic or felt underlayments.
✅ Budget & Longevity
Felt underlayment is affordable but less durable.
Synthetic underlayment costs more but lasts longer and is easier to install.
Rubberized asphalt is ideal for leak-prone zones but has a higher price point.
🔨 Where Is Underlayment Installed?
While full roof coverage is ideal, some areas demand extra attention:
Roof valleys
Eaves and rakes
Around chimneys, vents, and skylights
Beneath metal flashing
🏁 Final Thoughts: Don’t Overlook What Lies Beneath
A beautiful roof starts from the inside out. The underlayment is your roof’s safety net, ensuring long-term performance, durability, and protection. Whether you’re building a new roof or replacing an old one, investing in the right underlayment is non-negotiable.
📞 Need Help Choosing the Right Roofing System?
For expert roofing solutions, professional installation, and guidance on the best underlayment for your climate and structure.
At Scaffs India, we provide comprehensive roof inspection and repair services. Our team will assess the damage and ensure your roof is in top condition. Learn more about our roof repair services.
Scaffs India is your go-to expert for premium roofing shingles in Kerala—combining aesthetics, performance, and protection for every project.We invite you to explore some of the beautiful roofing choices.For more information regarding how IKO Roofing shingles can be used for your roofing project, visit our
contact page link here and get in touch. or call +91 96455 55534.