Roof Underlayment Replacement in Tampa, FL The Waterproofing Layer Under Your Tile

Why this is the repair that decides the roof

Tile is a sunshade and a rain deflector. It is not a sealed surface, and driven water moves between the pieces routinely. What catches that water and carries it back down to the eave is the membrane laid on the deck. Florida roofing guidance places tile service life at 50 to 100 years while putting the waterproof layer beneath it on a 20 to 25 year replacement cycle, which is why a roof can look sound from the street and still be finished as a water barrier. The other pages under our Tampa tile services all sit downstream of that one fact: a cracked piece, a slipped ridge or a rusted valley is a symptom, and the membrane is the patient.

What heat does to the layer nobody sees

Under dark tile the deck surface can run well past 150 degrees on a summer afternoon. Older asphalt-saturated felt does not tolerate that, because the heat drives the asphalt compounds out of the mat until it is brittle enough to crumble when a hand touches it. Florida contractor guidance reports failure of that older felt under dark tile in as little as 10 to 15 years. The Insurance Institute for Business and Home Safety is blunter about the material itself: asphalt-saturated felt is not waterproof, and it is known to fail when installed poorly, when made to a low specification, or after long ultraviolet exposure. That last item is why an uncovered slope during a repair is a schedule problem rather than an inconvenience.

Weight class is not a detail

Florida Building Code section 1507.3.3 accepts ASTM D226 Type II felt, or ASTM D2626 or D6380 Class M mineral-surfaced roll roofing, under tile. The state's own roofing fact sheet for the 2020 code tightened this further: where felt is used it must be 30 pound or equivalent, meaning D226 Type II or D4869 Type III or IV, and ply count, lap width and fastener spacing were all strengthened. The numbers behind those labels matter. D226 Type II carries a minimum of 26 pounds per hundred square feet; the Type I product often called 15 pound carries 11.5. In 2014 wind-driven-rain testing at the Insurance Institute one sheet sold as a 30 pound felt did not meet either heavy specification, failed at the ridge under high wind, and left the sheathing exposed. Ask which specification is going on your deck and get the answer in writing.

The slope of your roof changes the assembly

Tile is permitted from two and a half units of rise in twelve. Between that and four in twelve the code requires a double underlayment application, so the shallow hip roofs common on 1990s and 2000s stucco houses here are carrying two layers of the same aging material rather than one. For clay and concrete tile specifically, the state fact sheet points underlayment compliance at the FRSA and Tile Roofing Institute high wind manual, sixth edition, which was rewritten to line up with ASCE 7-16 wind loads. A crew quoting felt by the roll without naming that manual is quoting a shingle job.

Paperwork, inspections, and the open deck

Underlayment replacement is not spot work, so the permit questions arrive immediately. Hillsborough County's re-roof process runs a Progress Check inspection, which may be taken virtually with photographs, where the inspector confirms roof attachments were strengthened and corrected as the code requires, and a final only after that check or after a Roof Mitigation Verification Statement is uploaded through the county portal. The application itself carries an attestation under Florida Building Code B110, signed under penalty of perjury, that the existing decking, underlayment and covering will go in per code. Inside the city, roof work in excess of 500 square feet needs a permit and a tile roof needs a dry-in inspection before any tile is set. Practically that means the deck stays open until someone with authority looks at the new membrane, so the job needs a dry stretch of weather and a booked inspector, not just an available crew.

What the work involves and where the money goes

Tile is inventoried, lifted and stacked in courses so it can be reset in the same order. Old felt comes off, the deck gets read for rot and fastener condition, new membrane is laid with laps running downslope, penetrations and valleys are tied in, and the tile goes back with a breakage allowance because twenty-year-old pieces snap during handling. Cost tracks square footage, roof complexity and how much of the original tile survives the round trip, not the number of leaks you had. A scope worth signing names the underlayment product and specification, the number of plies, the measured area, the expected breakage percentage, and who is sourcing replacement tile if the profile is out of production. If only one slope has failed, say so on paper, because a documented section boundary is what keeps a partial job partial. When the pieces coming off are already breaking at the nail holes, read tile re-roof next; if the deck itself reads soft, roof deck and sheathing repair is the prior step.