When you get a roof replacement estimate in Volusia County, most of the conversation is about shingles — the color, the brand, the wind rating. But the layer you don’t see does just as much to keep your home dry: the underlayment. It’s the moisture barrier installed directly on your roof deck, underneath every shingle, and in Florida’s climate it’s one of the most important lines of defense your roof has.
At Affordable Roofing & Construction, we’ve been re-roofing homes across Daytona Beach, Port Orange, New Smyrna Beach, Ormond Beach, DeLand, and Deltona for more than 20 years. Here’s a straight-talk homeowner’s guide to what underlayment is, the three main types, and what actually makes sense for a Florida roof.
What Is Roofing Underlayment (and Why It Matters in Florida)?
Underlayment is the water-resistant layer that goes between your roof deck (the plywood or OSB sheathing) and your shingles. Think of it as a backup raincoat. Shingles are your roof’s first defense, but wind-driven rain — the kind we get in every Florida thunderstorm and tropical system — can push water sideways and underneath them. When that happens, the underlayment is what stops the water from soaking into your decking and dripping into your attic.
In Florida, underlayment isn’t optional and it isn’t an upgrade — the Florida Building Code requires it, and it must be properly fastened to withstand our high-wind zones. The question isn’t whether you have underlayment; it’s which type your contractor installs.
The 3 Main Types of Roofing Underlayment
1. Asphalt-Saturated Felt (“Felt Paper” / #15 or #30)
This is the old-school standard — the black “tar paper” you’ve probably seen on a roof under construction. It’s an organic or fiberglass mat saturated with asphalt to repel water. It comes in two common weights: #15 (lighter) and #30 (heavier, more durable).
- Pros: Lowest cost, widely available, familiar to every crew.
- Cons: Heavier, tears more easily in wind, absorbs some moisture, wrinkles when it gets wet, and degrades faster in Florida heat. If it’s left exposed before shingles go on, it can break down in days.
Our take: For a Florida re-roof, we generally recommend against basic #15 felt. If felt is used, #30 is the minimum — but synthetic has largely made felt obsolete for quality roofing.
2. Synthetic Underlayment
Synthetic underlayment is a woven polymer (polypropylene or polyethylene) sheet engineered specifically to outperform felt. This is what we install on the vast majority of our roofs.
- Pros: Far stronger and tear-resistant, much lighter, does not absorb water, resists wrinkling, holds up to UV and heat far longer if briefly exposed, and provides better footing for our crews. It also lays flatter, which gives your shingles a cleaner finished look.
- Cons: Costs more than felt — but the price difference on a full roof is modest compared to the protection you gain.
Our take: For Florida’s heat, humidity, and wind-driven rain, quality synthetic underlayment is the right baseline for most homes. It’s a small part of the total roof cost that pays off in durability.
3. Peel-and-Stick (Self-Adhered) Membrane
Also called self-adhering or “ice-and-water” membrane, this is a rubberized-asphalt sheet with an adhesive back that bonds directly to the roof deck. Because it’s fully adhered, it self-seals around nails and fasteners — even if wind lifts a shingle, water still can’t get through.
- Pros: The highest level of leak protection. Watertight seal around every fastener, superior performance in the most vulnerable areas of your roof.
- Cons: The most expensive option, which is why it’s typically used strategically in high-risk zones rather than across the entire deck (though full peel-and-stick decks are available for maximum protection).
Where we use it: Valleys, eaves, around chimneys and skylights, roof penetrations, and low-slope sections — the spots where Florida roofs leak first.
Underlayment vs. Secondary Water Barrier: Are They the Same Thing?
This is a common point of confusion. A Secondary Water Barrier (SWB) is a specific self-adhered layer — either a full peel-and-stick deck or taped deck seams — that can qualify you for an insurance premium discount on your wind mitigation inspection. So while all secondary water barriers are a form of underlayment, not all underlayment counts as an SWB for insurance purposes. If lowering your homeowners premium is a priority, ask us about adding a qualifying secondary water barrier during your re-roof — it’s one of the highest-value upgrades for a Florida home.
Which Underlayment Is Right for Your Volusia County Roof?
For most homes in our service area, the sweet spot is a quality synthetic underlayment across the field of the roof, with peel-and-stick membrane in the leak-prone areas (valleys, eaves, and penetrations). Homeowners who want maximum protection — or the wind mitigation insurance benefit — can step up to a full self-adhered deck.
The wrong move is letting price alone drive the decision toward the thinnest felt available. Underlayment is a relatively small line item on a re-roof, but it’s the difference between a roof that sheds a decade of Florida storms and one that lets moisture quietly rot your decking.
How We Do It at Affordable Roofing & Construction
Every roof we install includes:
- Quality synthetic underlayment as our standard — not bargain felt.
- Peel-and-stick membrane in valleys, eaves, and around all penetrations.
- Wind mitigation documentation to help you capture available insurance savings.
- A 5-year labor warranty on top of the manufacturer’s material warranty.
- Work performed by a licensed and insured contractor (CCC 1327602 & CGC 1509441) and CertainTeed-credentialed installers.
Get a Free Roof Estimate in Volusia County
Whether you’re planning a full re-roof or just want a straight answer about what’s under your shingles, we’re happy to take a look. We provide free, no-pressure estimates throughout Volusia County and Central Florida — Daytona Beach, Port Orange, New Smyrna Beach, Ormond Beach, DeLand, Deltona, and the surrounding areas.
Call us today at 386-392-8952 or request your free estimate online. Twenty years of local experience, licensed and insured, and quality materials from the deck up.
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