Roofing types · PVC & KEE (vinyl membranes)
PVC roofing: when the roof has to survive more than weather.
PVC is the premium thermoplastic: hot-air welded like TPO, but with decades more field history and real resistance to grease, chemicals, and standing water. It’s the default answer over kitchens and process exhaust — the places that quietly destroy other membranes.
Schedule My Free Roof Assessment01 · The system
What PVC is — and how it works.
PVC is a reinforced vinyl membrane, mechanically fastened or adhered, with hot-air welded seams that cure into a single sheet. Its chemistry shrugs off animal fats, many chemicals, and ponding water that would age other membranes — which is why restaurant chains standardized on it decades ago.
The trade-offs are cost and chemistry: PVC carries a price premium over TPO, its plasticizers slowly migrate out over decades (old PVC gets brittle at the end), and it can’t touch asphalt products without a separation layer. Detailing knowledge matters.
KEE changes that aging math. KEE (ketone ethylene ester) membranes replace the liquid plasticizers with a solid polymer that can’t migrate out — so the sheet stays flexible for its whole life instead of embrittling with age. KEE-modified PVC and high-KEE membranes (ASTM D6754) carry a further premium, and on roofs with heavy chemical exposure or a very long ownership horizon, they’re often the last membrane the building needs. The scan data — and your hold period — pick between them.
System profile
- Membrane
- Reinforced PVC (vinyl)
- KEE variants
- KEE-modified / high-KEE (ASTM D6754)
- Seams
- Hot-air welded
- Attachment
- Mechanically fastened / adhered
- Typical service life
- 20–30 years
- Surface
- Reflective white (colors avail.)
- Infrared candidacy
- Strong, over absorbent insulation
02 · Straight talk
Where PVC excels — and what to watch.
Where it excels
Grease and chemical resistance
The membrane of record over kitchens, food plants, and process exhaust.
Weld quality
Decades-refined weld chemistry; seams stay serviceable and re-weldable late in life.
Ponding tolerance
Handles standing water better than most single-plies — though we still fix the drainage.
Track record
The oldest thermoplastic in the field; its aging curve is well understood.
The KEE upgrade path
KEE membranes keep PVC’s weldability and chemical resistance but lose the plasticizer clock — flexibility for life, at a further premium worth pricing on long-hold buildings.
What to watch
Plasticizer migration
End-of-life standard PVC embrittles; a membrane flexibility check belongs in every assessment of an older roof. KEE membranes are the engineered answer to exactly this.
Asphalt incompatibility
Direct contact with asphaltic products attacks the membrane — a real risk during repairs by the wrong hands.
Cost discipline
The premium is worth it over exposure zones; on a plain warehouse, TPO often does the job for less.
Shattering in old age
Very old, cold, brittle PVC can crack under impact — one more reason baselines beat surprises.
Over a kitchen, PVC isn’t an upgrade — it’s the spec. Anywhere else, we’ll tell you whether it’s worth the premium.
03 · The lifecycle
How we manage PVC — from baseline to replacement.
Infrared maps moisture; a flexibility and seam check dates the membrane’s real age — not its calendar age.
LionCare keeps grease containment working and drains clear — the two failure accelerants on PVC roofs.
Hot-air welded patches with PVC-compatible materials only — diagnosed first, and never asphalt anywhere near it.
Sound PVC takes restoration systems matched to its chemistry; qualification testing decides.
End-of-life brittleness is measurable. When it arrives, replacement is planned on evidence, on your budget cycle — not after a shatter event.
04 · Questions
Frequently asked questions.
What owners ask about PVC roofs.
Is PVC worth the premium over TPO?
Over kitchens, food processing, and chemical exposure — yes, unambiguously; it survives what destroys TPO. On a clean warehouse roof the math is closer, and we’ll show you both numbers rather than defaulting to the expensive one.
How do I know if my old PVC roof is near the end?
Brittleness is the tell: plasticizer loss shows up in a membrane flexibility check long before widespread cracking. Combined with a moisture map, it turns ‘probably fine’ into a dated forecast.
Can you repair PVC installed by another contractor?
Yes — with PVC-compatible materials and hot-air welds to manufacturer spec, so any remaining warranty stays intact. The common fatal error is asphalt-based patching by generalists; it dissolves the membrane.
What is KEE, and is it worth it over standard PVC?
KEE (ketone ethylene ester) is a solid polymer that replaces the liquid plasticizers in standard PVC — so the membrane can’t embrittle the way aging vinyl does, and chemical resistance improves further. It costs more up front. On short-hold buildings, standard PVC usually pencils; on long-hold buildings and heavy-exposure roofs, KEE’s flat aging curve often wins the decade math. We’ll show you both numbers.
Evidence first
Own a PVC roof? Date it by evidence.
Flexibility, seams, and verified moisture — one assessment turns an aging PVC roof into a plan with numbers on it.
Schedule My Free Roof Assessment651-780-7663 · info@lionstarcommercialroofing.com