How Roofing Underlayment Helps Protect Your Home

You see the shingles on your roof every day, but what’s underneath them might be what truly keeps your home safe. If your roof leaks during heavy rain or winter ice dams, and you notice moisture in the attic, the problem might not be your shingles—it might be your roofing underlayment. But not all underlayment is created equal. Choose wrong, and you might as well wrap your roof in paper towels. Most homeowners don’t think about this hidden layer, yet it plays a major role in keeping your house dry, energy-efficient, and long-lasting.

In this guide, we’ll break down why roofing underlayment matters, the different types available, how it’s installed, and what you should look for when choosing one—especially if you live in areas with harsh weather.

What Is Roofing Underlayment?

Roofing underlayment is a water-resistant or waterproof barrier that goes between your roof deck and your shingles. Think of it like your home’s backup raincoat. If your shingles fail—because of wind, ageing, or poor installation the underlayment stops water from getting into your home.

There are many roof underlayment types, and the right one depends on your roof design and your local weather.

Why Is Underlayment So Important?

It doesn’t matter how expensive or beautiful your shingles are—without proper underlayment, your roof is vulnerable. Here’s what good underlayment does:

• Stops water from soaking into the wood deck

• Helps prevent mould and wood rot

• Acts as a secondary barrier during storms or snow

• Boosts roof lifespan

• Improves energy efficiency

That’s why investing in the best roof underlayment isn’t just smart—it’s necessary.

3 Main Types of Roof Underlayment

Not all underlayments are created equal. Let’s go over the main types you’ll see today:

1. Synthetic Roof Underlayment

• Cost: $0.50-$1.00 per sq ft
• Pros: Lightweight, tear-resistant, lasts longer
• Cons: Slippery when wet
• Best for: Most homes, especially in rainy/snowy areas

2. Felt Paper (Traditional Choice)

• Cost: $0.25-$0.50 per sq ft
• Pros: Affordable, breathable
• Cons: Tears easily, absorbs moisture
• Best for: Dry climates, budget projects

3. Peel-and-Stick Roof Underlayment

• Cost: $1.00-$2.50 per sq ft
• Pros: Self-adhesive, 100% waterproof
• Cons: Most expensive
• Best for: Ice dam zones, coastal homes, and valleys

How to Install Roof Underlayment (Key Steps)

While many choose to hire a roofing pro, understanding the process helps you see what you’re paying for.

1. Clean and prep the roof deck

2. Start at the eaves and roll up

3. Use proper overlaps (usually 2–4 inches)

4. Fasten using approved nails or staples

5. Seal around edges and valleys

If installing a peel-and-stick roof underlayment, ensure the surface is dry and warm for proper adhesion.

Speciality Underlayments for Different Roofs

Roof Type	Best Underlayment	Why
Metal Roof	Synthetic or rubberised	Prevents condensation
Tile Roof	Heavy-duty synthetic	Handles uneven surface
Flat Roof	Peel-and-stick	Seals completely

Pro Tip: Search for “metal roof underlayment” or “steel roof underlayment” if you have a metal roof—it needs specific types.

5 Signs Your Underlayment is Failing

🚩 Water stains on ceilings (but no missing shingles)
🚩 Musty attic smells (trapped moisture)
🚩 Shingles sticking to underlayment (means it’s absorbing water)
🚩 Visible sagging between rafters
🚩 Higher energy bills (poor insulation)

Final Thoughts

You wouldn’t wear a jacket without a shirt underneath in the winter, so don’t settle for shingles without strong roofing underlayment. Whether you’re researching the best underlayment for metal roofs or just figuring out how it’s installed, remember that this layer is key to protecting your investment.

If you’re unsure what kind of underlayment is best for your home, or you’re searching for trusted help, Procraft Home Products is here to make it easy for you. From Free inspections to full replacements, we’ve got you covered with reliable service and honest advice.