TPO is the membrane we spec most on the big flat roofs we work here, from plastics and packaging plants strung along the Berry Global corridor to warehouse buildings that back up to the Lloyd Expressway and I-69. It welds fast, it ships in wide rolls that cut down seam count, and it takes rooftop equipment loads better than most single-plies we've pulled off jobs in this market. Getting the spec right still comes down to what's actually happening on your deck, not a generic line item on a bid.
We don't hand you a mil thickness off a drive-by look at the building. Before we write anything down, we're up on the roof checking the deck itself, steel, poured gyp, or concrete, and probing the existing insulation with a moisture meter in a grid pattern instead of only at the low points. Wet insulation changes the whole plan. So does a deck that's already been recovered once or twice.
What's bolted to the roof matters just as much. A plant roof carrying condenser units, exhaust stacks, and process piping needs a different walkway layout and a different penetration count than an empty warehouse field. We map that before we quote mil thickness, because the number on the page should follow the roof, not the other way around.
Southern Indiana gets fast-moving spring and summer storm lines, straight-line wind gusts that hit harder than the forecast usually suggests, and hail mixed into more storm seasons than not. A membrane rated for a calm, low-exposure building isn't the number we use on a plant roof off US-41. We pull wind uplift ratings for the building's actual height and exposure category, then increase fastening density at the corners and perimeter zones where uplift pressure concentrates first.
Fully adhered systems generally hold up better through a wind event than mechanically fastened ones, especially on taller buildings or roofs with a lot of parapet exposure. Mechanically fastened still has a place on a lower, simpler field where cost matters more than the last few miles per hour of uplift resistance. Either way, the fastening pattern belongs in writing on the bid, not left as an assumption.
Humidity off the Ohio River sits on a flat roof longer than it does further inland, and a roof that doesn't drain within about two days after a storm starts growing algae streaks on white TPO before anyone in the office notices a problem. Ponding isn't cosmetic. Standing water finds every pinhole and stresses seams that were fine under normal drainage.
Tapered insulation fixes slope going forward, but only if it's built to the roof's actual drainage points instead of a generic layout pulled from a catalog. We confirm where the water is supposed to go before insulation goes down, not after.
Plastics and packaging buildings along the Berry Global corridor carry more roof penetrations than a typical office building, exhaust stacks, condenser curbs, process piping, and each one is a spot where a bad weld shows up first. On the open field, robotic hot-air welders lay a cleaner, more even bead run after run than a hand iron can hold for hours at a stretch, so that's the tool we default to there. Curbs and tight penetration clusters still come down to hand welding, and seam quality there depends entirely on whoever's holding the iron that day.
A leak over a production floor isn't the same problem as a leak over an empty storage bay. We probe every weld with a seam probe before we sign off, because catching a weak weld on the roof costs a few minutes. Catching it after it's dripping onto equipment below costs a lot more than that.
Warehouse and flex-industrial buildings tied to the supplier network feeding the Toyota plant up in Princeton mostly come to us with one recover layer already down. Whether a second recover makes sense or the roof needs a full tear-off comes down to what a moisture scan finds underneath, not how many years are left on the old warranty paperwork. Wet insulation sealed under a new membrane doesn't dry out. It just gets covered up until it fails again somewhere else.
Staging on these roofs isn't simple either. Buildings backed up to the Lloyd Expressway or I-69 corridor usually run active loading dock traffic that doesn't pause for a reroof, so we sequence crane placement, material staging, and tear-off sections around dock schedules instead of assuming a quiet, empty building underneath us.
60 mil covers most fields with regular equipment traffic. We go to 80 mil where foot traffic, mechanical loads, or penetration density push past what a 60 mil sheet handles well over time, and we'll walk you through the cost difference before it lands on paper.
It can, depending on hail size and membrane thickness. A thin membrane takes bruising or punctures that a thicker sheet shrugs off, one more reason mil thickness shouldn't get picked on price alone in a market that sees hail most storm seasons.
Fully adhered costs more up front but performs better in wind and around dense equipment clusters. Mechanically fastened is cheaper and still holds up fine on a simpler field with fewer penetrations and moderate exposure.
River humidity slows evaporation, so ponding that would dry out in a day somewhere arid can sit for most of a week here. Algae growth and membrane stress both start faster the longer that water stays put.
Most of the time, yes. We sequence tear-off and welding in sections and coordinate penetration work around exhaust and process equipment schedules so the crew below isn't shut down for the whole job.