PVC costs more than TPO, and the premium is justified in one situation: the roof is going to be exposed to something that eats other membranes. Kitchen grease, chemical exhaust, oils and fats. If the roof sees none of that, PVC is a more expensive way to get a welded white sheet. If it sees any of it, PVC is often the cheapest roof over twenty years, because it does not break down where others do.
In Coeur d'Alene, ID the choice also has to survive 60 psf of design snow and nights that have reached minus 30 F. We price the membrane and the snow details as separate lines, so you can see which one is driving the number.
The Call: When the Premium Pays
Restaurants are the textbook case. Exhaust fans throw grease onto the roof, and the grease works into most single-ply membranes over time, softening them and shortening their life. KEE, a PVC-alloy sheet, is the related choice when grease exposure is heavy. Hospitals and surgery centers have a similar issue with exhaust and cleaning chemicals, and manufacturing buildings can have solvent or oil in their exhaust streams.
On a plain office or warehouse roof with no special exposure, we usually show PVC as an alternate to TPO and let the owner see the difference. Some owners pay it for the thicker sheet and the longer track record on hard roofs. Others do not. Either answer is fine when the price is on the table.
What It Costs: The Premium and What Drives It
The membrane itself costs more per square foot than a comparable TPO, and PVC details such as corners, boots and flashings are often prefabricated, which adds cost. Insulation, cover board and fastening cost the same as for any single-ply. The difference narrows when the roof has many penetrations, because PVC's prefabricated details save field labor.
We list five lines: membrane, prefabricated details, insulation and cover board, edge metal, and drains. Tear-off is separate. If the old roof is dry, a recover avoids the tear-off line, though a recover over some old membranes needs a separation layer. We verify the old roof with infrared scanning and cores before we put a number on it.
Cover board is worth a look on PVC roofs that see traffic. A rigid board between the insulation and the sheet spreads foot loads and protects against hail from above, and it adds a line to the bid that we show as an alternate. On roofs with a lot of service visits, the board often pays for itself in avoided patches. On a quiet warehouse roof it may not.
Grease and Chemicals: What PVC Resists
PVC is a plastic membrane with plasticizers that keep it flexible, and it carries a reinforcing scrim for strength. The sheet is welded at the seams with hot air, so the seams fuse into the same material. The chemistry makes PVC resistant to animal and vegetable fats, to many acids and bases, and to a long list of rooftop contaminants. It does not make it immune. Strong solvents and some petroleum products still attack it, and we confirm what is on the roof before we specify.
For a restaurant, the call is simple. We detail the exhaust curb, add a grease catch if there is not one, and weld extra protection sheet around the discharge. For a clinic or a plant, we ask for the list of what comes out of the stacks.
Maintenance matters on a kitchen roof. Grease accumulates on the surface and in the curb, and a quarterly wash or a replaceable grease pad keeps it from building up. We leave a plain schedule with the manager, and our preventive maintenance program can carry it.
Where It Fits: Kitchens, Clinics and Labs
Sherman Avenue is the main commercial street in downtown Coeur d'Alene, and a restaurant building along it brings kitchen exhaust onto the roof. The Village at Riverstone, with its cinema, hotel and retail, is a mix where every exhaust needs its own detail. In Post Falls, healthcare employers such as Pleasant View Surgery Center and the Rehabilitation Hospital of the Northwest run exhaust and mechanical equipment that make PVC worth pricing.
Kootenai Health, the 329-bed hospital that is the county's largest employer, is the sort of building where a roof carries many penetrations, and prefabricated PVC details help there. The first step on any of them is a walk with the exhaust schedule in hand, so the membrane choice follows what actually comes off those fans.
Snow and Cold: How PVC Behaves in a North Idaho Winter
PVC stays flexible in cold weather, though cold sheet is stiffer to handle and slower to weld. The same drift pockets, drains and edge metal matter on PVC as on any roof. A white PVC surface does not shed snow faster than a dark one. It melts slowly in winter sun, so drains in shaded corners stay frozen longer, and we check their placement.
Wind sets the fastener pattern. We run it to the zone map for the city's 115 mph design wind speed and add perimeter attachment where the corners call for it. The point is the same as with TPO: the roof is only as good as its weakest edge.
Welds are the part we check hardest in cold weather. Every seam gets probed after it cools, and we test-weld at the start of each shift to confirm that heat and speed are right for that morning's conditions. Test welds are cut and pulled, and the results are kept with the job record. If a morning test fails, the crew waits for the sun or changes the settings. The roof does not get a weld that failed its own test.
Schedule: Prefabrication Saves Days
Prefabricated corners, boots and curb flashings arrive ready to weld, which speeds the detail work and reduces the hours a roof sits open. On a busy kitchen roof, that matters. We order details after we verify measurements on the roof, since a wrong boot size is a week of delay. The install window is the one every welded single-ply gets, running from spring thaw to the first hard freeze, and we open it in winter only when a failing roof leaves no choice. Compare the field time against a TPO bid and you will see where the prefabrication pays.
Closeout follows the TPO pattern: probe every seam, photograph every detail, and hand over the maker's warranty documents with the as-built notes. We add one PVC-specific check, a clean look at the exhaust area, so the first service visit finds a roof that is still protected.
Commercial Roofing Questions
Is PVC worth it for a restaurant?
Usually, yes. Grease damages most other membranes. PVC resists it, and the premium is smaller than a mid-life replacement.
Does PVC last longer than TPO?
On hard roofs, often. On clean roofs, the difference is smaller. Install quality matters more than the label.
Can PVC go over an old roof?
Sometimes. The old roof must be dry, and some old membranes need a separation layer. We test first.
Does PVC need a different warranty?
It carries its own manufacturer warranty, and the terms depend on the exposure. Send us the exhaust information and we will confirm the terms before the bid.
What does cold weather do to PVC installation?
It slows welding and stiffens the sheet. We adjust heat and speed and test more seams. Very cold days get moved.