The Layer That
Actually Keeps
Water Out
Shingles and tile shed water. What stops water reaching your ceiling is the membrane underneath — and it's the single biggest difference between a roof that lasts 25 years and one that fails in 12.
Your Roof Covering
Isn't Waterproof
This surprises most homeowners: shingles, tile, and metal panels are not a waterproof barrier. They're a shedding layer. Water gets past all of them.
Wind-driven rain pushes water sideways under shingle courses. Tile is designed to let water pass beneath it and drain out. Metal panels move as they heat and cool, opening tiny gaps at fasteners.
All of that is normal. It's supposed to happen. The underlayment beneath is what catches that water and carries it off the roof before it reaches your decking, your insulation, and your ceiling.
Which means the most important part of your roof is the part you'll never see — and the part a low bid quietly removes.
A completed underlayment layer — the roof beneath your roof
The Full Assembly,
Bottom to Top
A roof is a system. Here's every layer we put down, and what each one is actually doing.
Roof Deck
Every sheet inspected once the old roof is off. Soft, delaminated, or water-stained plywood gets replaced — and we give you the unit price before we start, so replacement decking is never an ugly surprise mid-job.
Re-nailed to current codeSecondary Water Resistance
A sealed barrier applied directly to the deck and its seams before anything else goes down. If your covering is torn off entirely in a hurricane, this is what stands between the storm and your interior. It's also the layer that earns credit on your wind mitigation inspection.
Insurance credit eligibleSelf-Adhered Underlayment
We specify [BRAND-SA] — a peel-and-stick membrane that bonds fully to the deck rather than being nailed over it. Fully adhered means no gap for wind to get under, and the membrane self-seals around every fastener driven through it.
Florida Product Approval [FLPA-SA]Valley & Penetration Detailing
Extra membrane at valleys, then metal flashing over it. Pipe boots, vents, skylights, chimneys, and wall intersections each get their own detail. Roofs almost never leak in the open field — they leak where two things meet.
Drip Edge & Starter
Metal drip edge at eaves and rakes, installed in the correct sequence relative to the underlayment. Get that order wrong and you've built a funnel that directs water into your fascia instead of away from it.
Your Roof Covering
Shingle, tile, metal, or flat membrane — fastened to the pattern the code and the manufacturer require, not the pattern that's fastest. Six nails where six are called for.
Felt vs. Synthetic vs.
Self-Adhered
Three products, three price points, three very different outcomes in a Florida storm. This is where quotes differ far more than most homeowners realize.
| #30 Felt | Synthetic | Self-Adhered | |
|---|---|---|---|
| How it attaches | Nailed or capped | Nailed or capped | Bonded to the deck |
| Seals around nails | No | No | Yes, self-sealing |
| If covering blows off | Usually goes with it | Often tears at fasteners | Typically stays put |
| Handles standing water | Poorly — absorbs and wrinkles | Better | Designed for it |
| Heat tolerance | Dries out and cracks | Good | Formulated for FL heat |
| Exposure window | Days | Weeks | Months |
| Relative cost | Lowest | Moderate | Highest |
We install self-adhered membrane as our standard specification on Florida re-roofs. It costs more up front. On a roof that has to survive hurricane season, it's the layer we're least willing to compromise on.
The Line Item Your
Insurer Cares About
If you've renewed a Florida homeowners policy recently, you've probably seen the phrase "secondary water resistance" and had no idea what it meant.
SWR is a sealed barrier applied to the roof deck and its joints — underneath everything else. Its job is a worst-case job: keep water out when the roof covering is gone.
Because it materially reduces the damage a hurricane does to a home's interior, it's one of the items a wind mitigation inspector specifically checks — and one that carriers credit.
We install it, we document it, and we give you the paperwork your inspector will ask for.
About Insurance Savings
You'll see contractors advertise specific dollar figures for wind mitigation savings. We won't, because the number depends entirely on your carrier, your policy, your home's other features, and your county.
What we will do is give you complete documentation so your inspector can credit every feature your roof actually has. Then your agent can tell you the real number for your policy. That's a conversation worth having before you choose a specification, not after.
Nothing Works on
a Bad Deck
The best membrane on earth cannot bond to rotted plywood. Once the old roof comes off, we walk every square foot of decking — and where it's soft, delaminated, or water-stained, it gets replaced.
Florida code also requires re-nailing the deck to current standards on most re-roofs, because older homes were often built to fastening patterns that no longer meet the wind loads we design for.
Because we hold a general contractor license alongside our roofing license, we can address rotted fascia, damaged trusses, and structural repairs directly — instead of stopping your job while you find a second contractor and wait.
Four Questions Worth Asking
Every Contractor
Including us. Two roofing quotes that look $6,000 apart are often quoting entirely different roofs — and the difference is almost always in this layer.
If a quote is dramatically cheaper than the others, this is usually why. Not because someone found a better price on labor — because a layer got removed from the specification and nobody mentioned it.
Underlayment FAQs
What is roof underlayment?
Underlayment is a water-resistant membrane installed directly onto the roof deck, beneath your shingles, tile, or metal. Your roof covering sheds most water; the underlayment catches whatever gets past it and drains it off the roof before it reaches your decking and ceiling. It's the actual waterproofing layer of the assembly.
What is secondary water resistance, and do I need it?
SWR is a sealed barrier applied to the roof deck and its joints, designed to keep water out even if the roof covering is completely removed by a storm. Florida code requires it in many re-roof situations, and it's one of the specific items a wind mitigation inspector checks — which means it can reduce your insurance premium. Requirements vary by county and by the scope of your project, so confirm what applies to your address.
Is peel-and-stick underlayment worth the extra cost?
In Florida, we think so, and it's our standard specification. Self-adhered membrane bonds to the deck rather than being nailed over it, so there's no gap for wind to get under, and it self-seals around every fastener driven through it. In a storm that strips your shingles, a nailed felt underlayment usually leaves with them. A bonded membrane typically stays put — which is the difference between replacing a roof and replacing a roof plus drywall, insulation, flooring, and contents.
Can underlayment be replaced without replacing the whole roof?
Not really. The underlayment sits beneath the covering, so reaching it means removing what's on top. On tile roofs this is sometimes done as a "lift and relay" — the tile is carefully removed, new underlayment installed, and the original tile reset. That's a genuine option when the tile is in good condition and the underlayment has aged out, which happens often on Florida tile roofs since the tile outlasts the membrane beneath it.
How long does underlayment last?
Quality self-adhered membrane is generally designed to last as long as the covering above it. Traditional felt degrades considerably faster in Florida heat — it dries out, becomes brittle, and cracks. That's a common reason tile roofs need attention long before the tile itself has failed.
My roof isn't leaking. Why does this matter?
Because underlayment failure is invisible until it isn't. Water reaching the deck can spread through insulation and framing for months before it appears on a ceiling, and by then you're repairing structure rather than roofing. Our free inspection includes an attic check where there's access — which is usually where the early evidence shows up first.
Does underlayment go under tile and metal too?
Do you document what you install?
Yes. You get photos of the deck condition, the underlayment installed, and the detail work at valleys and penetrations — before any of it is covered up. Along with your permit records and wind mitigation paperwork, that's the file that proves what's actually on your roof. Ask any contractor whether they provide it.
Roof Systems We Install Over It
Underlayment is the foundation for every covering we install: architectural shingle, concrete and clay tile, standing seam metal, and 5V panels. For low-slope sections, see TPO and silicone restoration.
Planning a full re-roof? See residential roof replacement, or start with a free roof inspection.
Find Out What's
Under Your Roof
Free inspection with attic access where available, photos of what we find, and a written specification that names every layer by product. No guessing what you're buying.