Commercial Roofing
Gray, cracked asphalt with a handful of blisters, a tight budget and no appetite for a dumpster-filled tear-off: that combination is where KEE membranes come up in conversation. Most single-ply sheets cannot be laid directly over old asphalt without trouble, and one that can is worth a closer look than its odd name usually gets.
In Edinburg, TX asphalt roofs soften under a long heat season and then absorb tropical rain, so a membrane that tolerates old roofing, oils and heat can spare an owner a full removal. We install and repair KEE, and we say so when another sheet fits the building better. The question to settle first is what is on the roof today and whether it is dry.
The letters stand for ketone ethylene ester, a polymer that takes the place of much of the liquid plasticizer in an ordinary PVC membrane. Liquid plasticizer slowly leaves a sheet and leaves it brittle. A polymer that stays put keeps the membrane supple longer, and it lets the sheet touch asphalt and some insulations without being attacked.
Everything else behaves like a thermoplastic single-ply. Hot air welds the seams into one piece, scrim reinforces the sheet, and rolls are laid, welded and flashed like other membranes. Each manufacturer formulates its KEE product differently, so the project specification and the installation instructions for the exact sheet govern the details.
Often it can. On an aged built-up or multi-ply asphalt roof, or on a modified bitumen roof, the old assembly is left alone, a cover board or slip sheet is added where the manufacturer asks, and the KEE sheet follows. The owner skips tear-off, noise and dust, and the old roof becomes added insulation and a second line of defense.
All of that depends on dry insulation. An infrared moisture survey and a set of cores find wet spots, and soaked material is cut out before anything new is laid. Blisters and ridges are cut flat or removed, and low spots are filled so water runs. This is the path our recover and overlay work follows, and the old roof is judged by its readings, not by how it looks from the lot.
Heat has already worked on the old asphalt. Softened bitumen leaves ridges and low spots, and hardened bitumen crazes. Either can telegraph through a new sheet, so the surface is prepared and photographed before it is covered.
Restaurants, food plants, labs and industrial buildings put things on their roofs that eat other membranes. KEE resists many compounds that soften EPDM and certain TPO formulations, and it tolerates hot exhaust blowing across the sheet near vents.
Edinburg's economic development group lists food processing and manufacturing among local employers alongside distribution and warehousing, healthcare and government. Which of those buildings has exhaust that actually lands on its roof is a matter for each building's equipment, so we ask before recommending a sheet. Roofs under exhaust get a cleaning route, and drains are checked after each cleaning, because loosened grease and grit settle at the low point.
Heat-safety season, May to October, and hurricane readiness, June to October, both appear on the weather service's Valley calendar. A sheet that stays flexible through the heat is less prone to pull away from walls, though flashing terminations are checked on every visit. KEE welds are strong, but each weld is only as good as the surface it was made on.
After tropical wind we walk edges, flashings and rooftop equipment on every membrane we care for. On KEE we also check that perimeter bars and fasteners have not worked loose and that laps near corners are intact. A hurricane damage repair record notes what moved, what held and what still needs a closer look once the roof is dry.
Welds need a clean, dry sheet, correct temperature and travel speed, and a probe along every seam. A Valley afternoon can switch from dry to wet in an hour, so welding is scheduled for the drier part of the day and a cover waits near the work. Between passes, the seam probe is run along each weld and the result is marked on the plan.
Thick, stiff sheet needs careful handling at details. At corners, penetrations and wall transitions, pre-formed pieces and PVC-coated metal are welded to the field sheet. Over-tight flashing fights the sheet, so it is relaxed and each termination is checked. Rolls are heavy, and the crew stages them to avoid creases. A scuff or crease made before welding becomes a thin spot that the weld cannot fix, so rolls are never dragged across rough surfaces or sharp edges. Repairs are simple when caught early: patches with rounded corners and generous overlap, edges probed. When damage keeps returning to one area, we look under the sheet for soaked insulation, a deck that has sagged or a drain set too high, none of which a patch can cure. A membrane puncture repair follows the same cleaned and probed weld.
TxDOT lists improvements to Doolittle Road and FM 2812 in Edinburg, tying commercial properties to the north-side network, and the city places its northern edge along the I-69C and US 281 corridor. A distribution or warehouse building along those roads may carry an asphalt roof, and where it does a recover membrane is weighed against a full replacement.
For owners in the north Edinburg commercial corridor and the rest of Edinburg, we set KEE against PVC and multi-ply asphalt for the particular roof and use, and the City of Edinburg's adopted 2018 International Building Code and Energy Conservation Code are checked whenever insulation changes. When a simpler sheet is enough, we tell the owner.
Cost comes down to a few drivers: how much of the old roof must come out, whether a cover board is required, the number of penetrations and wall details, and the thickness of sheet specified. The estimate shows each as its own line, with a wet-insulation allowance priced by the square, so the owner can see what a smaller or larger wet area would change. Dry-in sequence, protection below the deck and closeout photographs are written into the scope as well, because a recover on an occupied building is judged as much by how cleanly it is staged as by the sheet it ends with.
Much of the liquid softener is replaced by a polymer that does not leave the sheet, so KEE stays flexible longer and can touch asphalt. Plain PVC needs a barrier from asphalt.
Frequently, with a cover board or slip sheet if the manufacturer asks for one, so long as the old roof tests dry and reasonably flat.
It is among the sheets chosen below exhaust and grease, and we measure it against PVC using the real equipment and layout.
Mostly at details: pulled flashing, a hurried weld, a puncture next to a unit. Age appears as stiffness and shrinkage, which the formulation resists.
Yes, since a second roof sits on top of the first. The deck and structure must carry both, and capacity is checked before we recommend it.