Reading a Roof

The Roofing Series, Lesson 2 · Taught by Professor Elias Walls · Researched and reviewed by Grant Doutt, Certified Master Inspector®

🎓 The Professor's Quick Answer

Every roof in Florida is really two roofs: the covering you can see, and the waterproof layer underneath that actually keeps water out. Each material fails in its own way, and almost never the way homeowners expect.

Asphalt shingles wear out on the surface, and in Central Florida we rarely see one make it past 20 years, architectural shingles included. Tile roofs almost never fail because of the tile; they fail because the underlayment beneath has cooked, usually in 15 to 25 years for the felt systems under most Florida roofs today, while the tile itself is good for decades more. Metal roofs outlast everything, and the weak points are the fasteners and the edges. Flat roofs live or die by one thing: whether the water gets off.

Learn to read which one you have, and you'll know what to expect from it, what your insurer will ask about it, and roughly where it is in its life.

🏫 Welcome Back to the Knowledge Center

Last class, we learned the roof clock: how Florida counts a roof's age and why that number carries so much weight with insurers. Today we climb up on the roof itself.

The purpose here isn't to turn you into a roofer. It's so that when an inspector hands you a report, or a contractor stands in your driveway and starts talking, you understand what's being described and can ask the next question.

🧱 A Roof Is a System, Not a Surface

Before we get to materials, understand what's actually stacked up over your head. From the top down:

1. The covering: shingles, tile, metal panels, or membrane. It sheds most of the water and takes all of the sun.

2. The underlayment: the waterproof or water-resistant layer over the wood. This is the real barrier. Water that gets past the covering is supposed to hit this and run off.

3. The deck: the plywood or board sheathing nailed to the trusses. Wet decking is how a roof leak becomes a structural repair.

4. The flashing: the metal at every place the roof meets something else, which is where most leaks actually start.

5. The attic and its ventilation: the space underneath, which both tells the story of the roof's health and helps determine how long it lasts.

Hold onto number 2. Most of what surprises Florida homeowners about roofs comes from not knowing the underlayment exists.

🟫 Asphalt Shingles

Most common roof in Florida, and the one that takes the worst beating from the sun.

Two kinds. Three-tab shingles are flat, thin, and uniform, with a repeating notched pattern, and they're what you'll find on many older homes. Architectural (or dimensional) shingles are thicker and layered, with a shadowed, random look. Architectural shingles are heavier, generally hold up better in wind, and cost more.

How long they last here. Manufacturer ratings assume an average American climate. Florida is not that. You'll see 25- and 30-year shingles advertised, and the box isn't lying about the product; it's describing a roof that doesn't sit under this sun.

In the field in Central Florida, we rarely see a shingle roof make it past 20 years, and that includes architectural shingles. Three-tab roofs tend to show their age earlier still. Treat the high end of any manufacturer's rating as a best case that assumes a milder climate, good attic ventilation, and a clean install.

So if you're planning around a shingle roof here, plan on somewhere in the 15 to 20 year range and treat anything beyond that as borrowed time.

How they age, in the order you'll see it:

• Granule loss. Those ceramic granules are the shingle's sunscreen. When they wash into the gutters and downspouts, the asphalt underneath starts baking.

• Curling and cupping. Edges lift or the center dishes as the shingle dries out and shrinks.

• Cracking and brittleness. An old shingle snaps instead of bending.

• Lifted or missing tabs. Usually wind, often along edges and ridges where uplift is strongest.

• Exposed or raised nails. Every exposed nail head is a future leak.

What matters at install. How many nails per shingle, and where they're placed. In Florida's wind zones, nailing patterns and the fastening of the deck itself are governed by code, and they're also part of what determines your wind mitigation credits. That's next class.

🟧 Tile: The Roof That Fails From Underneath

This is the one homeowners get wrong most often, and it costs them real money.

Clay versus concrete. Clay tile is kiln-fired, hard, and extremely durable, commonly lasting 50 years or more. Concrete tile is a bit softer and more absorbent, and generally runs 25 to 50 years. Both far outlive any shingle.

But the tile isn't the clock. Underneath those tiles is the underlayment, and in Florida's heat it's the part that wears out first. Heat gets trapped beneath the tile, humidity works on it, and the material goes brittle and cracks along the laps and fastener lines. Older felt systems commonly reach the end of their life in roughly 15 to 25 years, while newer synthetic and self-adhered membranes generally last longer.

That produces the single most misunderstood situation in Florida roofing: a tile roof that looks perfect from the street and is actively leaking. Every tile intact, nothing cracked, water coming through the ceiling, because the layer nobody can see has failed.

What a "tile roof replacement" usually is. In most cases the tile is lifted and stacked, the old underlayment is stripped to the deck, damaged sheathing is replaced, the deck is re-nailed, new underlayment goes down, and the same tile goes back on. New tile is bought only to replace what broke in handling. Roofers call it a re-lay or a rebuild, and it costs meaningfully less than a full new tile roof. If a contractor is quoting all new tile on a roof whose tile is sound, ask why.

What we look for on tile:

• Cracked, broken, chipped, or slipped tiles, which means the fastening beneath has let go

• Deteriorated mortar at ridges and hips

• Repairs where mismatched tile or caulk has been used to chase a leak

• Cracked tiles caused by people walking a tile roof incorrectly, which happens more than it should

• Evidence in the attic of underlayment failure: staining, damp sheathing, previous patch repairs

🧪 The New Underlayments: Better, but Unproven

Everything said above about underlayment life comes from felt, because that's what is under most Florida roofs today. What's going on a roof now is a different animal.

The older system is asphalt-saturated felt, rolled out and mechanically fastened with nails or tin caps, with the sheets overlapped. Two things end it: the heat drives the volatiles out of the asphalt until it goes brittle, and it cracks along the two weakest lines on the roof, the laps where sheets overlap and the rows of fastener holes.

The newer self-adhered products, which the trade calls peel-and-stick, work differently. The membrane is bonded directly to the wood deck rather than nailed through, so there's no row of holes running across it, and the seams are sealed, with the sheathing joints taped. The result is a continuous sealed surface instead of a layered, punctured one. On paper, the two failure paths that end a felt system are largely designed out.

Here's the honest part, and it's the reason this section exists. These products haven't been on Florida roofs long enough to have a track record. Manufacturers publish long service-life expectations, and the early performance looks good, but a lifespan number is earned by watching roofs fail, and not enough of these have reached the end of their lives here for anyone to say with confidence how long they last in this heat.

So treat the numbers earlier in this lesson as what they are: the record of felt, which we do know. For a roof built with a fully adhered membrane, the reasonable expectation is that it should outlast felt. How far past, nobody honestly knows yet.

And when the attic is spray-foamed

There's one combination worth knowing about: a sealed membrane above the deck and spray foam against the underside of it.

Foam under the roof deck has real advantages. It brings the attic and the air conditioning equipment inside the conditioned space, and closed-cell foam at the sheathing-to-truss connection measurably strengthens the roof against wind uplift.

But it changes what a leak looks like. The industry's own warning is blunt: when water gets past the roof covering onto a foamed deck, the usual warning signs don't appear. The water can sit between the foam and the wood while the attic side of the foam looks perfectly dry, and the damage can go unnoticed for months. In the worst cases a ceiling stain doesn't show up until the structure above it is badly gone.

Now stack the sealed underlayment on top and the wood has no easy path to dry in either direction, and no one can see it from either side.

That leads to three practical rules:

• Never foam over a roof you haven't dealt with. If the covering is near the end of its life, re-roof first. Foam doesn't fix a leak; it hides one.

• Confirm the deck is dry and sound before it's covered, and fix anything that isn't.

• If a home already has a foamed attic, expect leak detection to depend on moisture meters and infrared scanning rather than looking for stains, and expect that a future deck repair means removing foam to get at the wood.

What this means practically:

• If you're re-roofing, ask your contractor specifically what underlayment is going down and how it's attached. That answer, more than the brand of shingle or tile, determines how long the system keeps water out.

• If you're buying, find out what's under the covering. A 12-year-old tile roof over hot-mopped felt and a 12-year-old tile roof over a fully adhered membrane are not in the same position, even though they're the same age on paper.

• Keep the paperwork either way. What's under there is invisible once the covering goes on, and the invoice is the only record of it.

• Ask about attic ventilation. With a sealed deck, ventilation is what gives moisture a way out. It matters more now than it did under felt.

⬜ Metal

The longevity champion in Florida, and increasingly common on new homes.

Two families. Standing seam hides its fasteners under raised seams, which is the more durable design and can run 40 years or more. Exposed-fastener panels, including the 5V crimp panels common on older Florida homes and outbuildings, are screwed through the face of the panel with rubber-washered screws.

Where metal roofs actually fail: almost never in the middle of a panel.

• Fasteners. On exposed-fastener roofs, the rubber washers harden and shrink with age, and screws back out as panels expand and contract in the heat. Re-screwing is routine maintenance on these roofs, not a defect on its own.

• Edges and penetrations. Flashing at valleys, ridges, walls, and pipe boots.

• Corrosion. Cut edges, scratches, and panel ends, especially near the coast or where dissimilar metals touch.

• Oil canning, the waviness you sometimes see in flat panel areas, which is cosmetic and not a failure.

One insurance note. A metal roof's long life doesn't exempt it from the roof clock. It's still dated from its installation, and insurers still ask.

⬛ Flat and Low-Slope Roofs

Florida has plenty of these: additions, porches, carports, mid-century homes, and most commercial buildings.

What they're made of. Modified bitumen is a rolled asphalt membrane, often torch- or self-adhered, common on residential flat sections. Single-ply membranes like TPO are large welded sheets, usually white. Built-up roofing, the old layered tar-and-gravel system, still turns up on older buildings.

These are shorter-lived than the pitched roofs above, and they have their own vocabulary of failure:

• Ponding water. Water that sits for more than a day or two after rain. Flat roofs aren't truly flat; they're supposed to drain. Standing water is the beginning of the end.

• Seams and laps. The joints between sheets, which is where most leaks begin.

• Blisters and bubbles. Trapped moisture or air expanding under the sun.

• Clogged or undersized drains and scuppers, which turn a rainstorm into a pond.

• Cracked or worn coatings on older systems.

If a home has a flat section over an addition or a porch, expect that section to need attention on a different schedule than the main roof. In practice, it's often the piece that leaks first.

☀️ What Florida Does to All of Them

Whatever material you have, four forces are working on it every day:

• Ultraviolet light, which breaks down asphalt, plastic, sealants, and rubber. It's why our roofs age faster than the same roof in Ohio.

• Heat cycling. Everything expands under the afternoon sun and contracts at night, over and over, loosening fasteners and working on seams.

• Water, from afternoon storms and wind-driven rain that can push uphill under coverings that shed ordinary rain fine.

• Wind and debris, from storm season, which lifts edges, loosens tabs, and drops branches.

There's also one force people forget: foot traffic. Air conditioning techs, satellite installers, pressure washers, and well-meaning homeowners all walk on roofs, and on tile and aging shingle, walking is damage.

🔦 What the Attic Tells Us

Some of the most useful roof evidence is found from the inside, in the attic, and it's where a lot of inspection findings actually come from:

• Water stains on the decking or rafters, and whether those stains are old and dry or currently damp

• Daylight where there shouldn't be any

• Rusted or shiny nail points, a sign of condensation

• Soft, delaminated, or previously replaced sheathing

• Ventilation, because a poorly vented attic bakes the underlayment from below and shortens the life of the whole roof

This is why an inspector who never leaves the driveway isn't inspecting your roof.

🏛️ How Insurers Read the Material

Tying this back to Lesson 1: insurers divide roofs into two buckets.

• "Soft" roofs, meaning shingle and similar coverings, come under scrutiny at a younger age. Citizens, for instance, requires documentation on shingle roofs older than 25 years.

• "Hard" roofs, meaning tile, slate, clay, concrete, and metal, get much longer runway. Citizens draws its line at 50 years for those.

Here's the catch for tile owners. Your insurer asks when the roof was replaced. If your underlayment was redone and the same tile went back on, that's a full roof replacement and it resets your clock, but only if you can prove it. Keep the permit and the contractor's paperwork from a re-lay. Without those, you're a tile roof of unknown age with no documentation, which is a hard spot to be in when the renewal notice comes.

❓ Questions From the Back Row

"My tile roof looks brand new. Why is my insurer asking questions?"

Because they're asking about the roof's age, not its appearance, and because the underlayment that actually waterproofs a tile roof has a much shorter life than the tile. A 30-year-old tile roof with original underlayment is a real risk, no matter how good the tile looks.

"Can I just replace the underlayment and keep my tile?"

That's usually exactly what's done. The tile is lifted and reset over new underlayment. Just make sure it's permitted, and keep the paperwork.

"How do I tell three-tab from architectural shingles?"

Look at the pattern. Three-tab is flat and uniform with evenly spaced notches, like a repeating rectangle. Architectural is thicker and looks random and shadowed, more like wood shakes.

"My metal roof has screws backing out. Is it shot?"

Probably not. On exposed-fastener metal, re-screwing with oversized fasteners and fresh washers is normal maintenance. What matters is whether water has gotten in and damaged the decking underneath.

"There's water standing on my flat porch roof two days after a storm. Normal?"

No. Ponding water is a problem on any low-slope roof, and it shortens the life of the membrane underneath it. Find out whether it's a drainage issue or a sagging deck.

🚌 Field Trip — Class Dismissed

Go outside and identify what you have. Shingle, tile, metal, flat, or some combination, which is very common: a tile main roof with a flat section over the back porch, or a metal carport attached to a shingle house.

Then look at the gutters and the ground around the downspouts. If you see a buildup of dark granules like coarse sand, your shingles are shedding their sunscreen. And after the next hard rain, check any flat section for water still standing a day later.

Next class: what holds your roof on. Nails, clips, straps, and secondary water barriers, the wind mitigation report, and how those details can lower what you pay for insurance.

Sources: Florida roofing industry lifespan data for shingle, tile, metal, and low-slope systems in Florida's climate; Citizens Property Insurance Corporation published roof eligibility requirements. Material lifespans are typical ranges, not guarantees; any specific roof should be evaluated on its own condition.

Buying a home in Clermont, Lake County, or anywhere in Central Florida? Call (352) 272-1322 or visit fourcornershomeinspections.com.

Taught by Professor Elias Walls · Researched and reviewed by Grant Doutt, Certified Master Inspector® · Last reviewed: September 2026. Professor Elias Walls is the teaching persona of the Four Corners Knowledge Center. Every lesson is researched, written, and fact-checked by the licensed, certified inspectors of Four Corners Inspection Services.