Updated August 2026
Search for vinyl decking in Ottawa and you will get two kinds of company answering, selling two products that have almost nothing in common. One is a plank: cellular PVC boards that screw or clip down onto joists the same way composite does, and that most people mean when they say vinyl. The other is a sheet: a waterproof PVC membrane rolled and welded over a solid surface so the space underneath stays dry. One is a deck surface. The other is closer to a flat roof you are allowed to walk on. If you ask three contractors for a vinyl deck quote you can get three prices that are not comparable, because you have not all been talking about the same thing. This guide separates them, says which one your project probably needs, and tells you what to ask so the quotes line up.
The two products, side by side
Cellular PVC boards are solid plastic planks. There is no wood flour in them, which is what separates them from composite, and they install on a joist frame like any other decking. This is what most Ottawa homeowners mean by vinyl decking, and it is what almost every deck builder in the city is quoting when you use the word.
Vinyl membrane is a different trade. It is a PVC sheet laid over a solid substrate and heat-welded at the seams into one continuous waterproof surface. Duradek, which has been making it since 1974, describes it as a single product solution for long-lasting waterproof protection and calls the perfect application elevated decks that need a dry area below, or flat roof decks over living space. That is the giveaway: membrane exists to keep water out of what is underneath.
So the question that sorts them is not which looks better. It is whether anything under your deck needs to stay dry.
| Sold as | What it actually is | What it is for | How it goes down |
|---|---|---|---|
| Vinyl decking, vinyl deck boards | Cellular PVC planks, no wood content | A low-maintenance walking surface on a normal deck frame | Screwed or hidden-clipped to joists, gaps between boards |
| Vinyl decking, vinyl sundeck, sundeck covering | A PVC membrane sheet, seams heat-welded | Keeping the space below dry: a balcony over a room, a deck over a garage or walkout | Rolled over a solid substrate and welded into one continuous surface |
| Composite decking | Wood flour and plastic, usually PVC-capped | A wood look with less maintenance than cedar | Same as PVC boards, on joists |
| Pressure-treated or cedar | Wood | The lowest build cost, and the most upkeep | Screwed to joists |
Which one your project needs
If your deck sits over open air, over gravel, or over anything you do not mind getting wet, you want boards. Water passes between them, the frame below is built to live outdoors, and the whole assembly dries after it rains. Adding a waterproof membrane to that deck buys you nothing except a bill.
If your deck or balcony is over a finished room, a garage, a walkout basement or any space you want to keep dry, a board surface alone will not do it. Water goes through the gaps by design, so the waterproofing has to happen underneath, and that is a membrane or a proper roof assembly rather than a decking choice.
The third case is the one people get wrong: a deck built over a walkout with a plan to store things underneath. That is not a decking question either, and deciding it after the frame is up is what turns a deck into two projects.
What Ottawa's winter does to each
Ottawa's freeze-thaw cycle is a water problem before it is a cold problem. Water gets into a place it should not be, freezes, expands and pushes. Every material argument on this site comes back to that, and it applies here in two different ways.
With boards, the water is supposed to pass through and drain, so what matters is the frame below, the fasteners and how the surface handles ice and salt. Our PVC page covers that in full, including how far cellular PVC moves with temperature and what that does to fastening in a climate that swings from minus thirty to plus thirty.
With a membrane, the entire job is to be a continuous surface with nowhere for water to enter, which is why seams are welded rather than glued and why the substrate has to be sound before the sheet goes on. Duradek states that its system is installed by trained and authorized installers only, which is a fair signal of how much the workmanship matters on that product.
How to make three quotes comparable
Ask each contractor one question before anything else: is the price for boards on a frame, or for a waterproof membrane system. That single sentence usually explains a spread that looked inexplicable.
Then ask what happens to water. If the answer is that it drains between the boards, you are buying a deck surface. If the answer is that the surface is sealed and the water runs off it, you are buying a waterproofing system, and it should come with the manufacturer's warranty and the name of the authorized installer.
Two quotes for two different products are not competing. Pick the product first, then compare prices inside it.
What we build, and what we will tell you straight
We build decks in cellular PVC, composite, cedar and pressure-treated, on frames we build ourselves. If you want the low-maintenance plastic board most people mean by vinyl decking, that is our PVC deck page and it is the honest answer to the search.
Membrane systems are a manufacturer-authorized trade, so if what you actually need is a dry room under a balcony, say so on the first call. We would rather tell you that on the phone than have you find out after a frame is up. Either way you get an answer that fits the project instead of the word.
Source: PVC deck builder in Ottawa
Common questions
Is vinyl decking the same as PVC decking?
Usually yes, and sometimes no, which is the whole problem with the word. Most Ottawa contractors saying vinyl decking mean cellular PVC boards: solid plastic planks with no wood content that install on joists like composite. Others mean a PVC membrane sheet that is welded into a continuous waterproof surface over a solid substrate. Both are PVC. One is a plank and one is a sheet, and they are not quoted the same way.
What is a vinyl sundeck?
That is the membrane product. A PVC sheet is laid over a solid surface and its seams are heat-welded so the finished deck is continuous and waterproof. Duradek, which has made this since 1974, describes the ideal applications as elevated decks that need a dry area below and flat roof decks over living space. If you are searching for a vinyl sundeck covering, the space under your deck is the thing you are actually trying to solve.
Do I need a waterproof membrane under my deck?
Only if something below it needs to stay dry. A deck over open air or gravel does not need one: water passes between the boards, the frame is built to live outdoors, and the assembly dries out. A balcony over a finished room, a deck over a garage, or a walkout you plan to store things under is the case where board gaps are a problem and the waterproofing has to happen underneath the surface.
Why are my vinyl deck quotes so far apart?
Usually because they are not quotes for the same product. A price for cellular PVC boards on a frame and a price for a welded membrane system are two different scopes of work. Ask each contractor whether the number covers boards on a frame or a waterproofing system, and ask what happens to water: drains between the boards, or runs off a sealed surface. Then compare prices inside one product.
Does Ottawa's freeze-thaw affect vinyl decking?
It affects both, differently. With boards the water is meant to pass through and drain, so what matters is the frame, the fasteners and how the surface handles ice and salt, and cellular PVC moves a noticeable amount with temperature in a climate that swings from minus thirty to plus thirty. With a membrane the entire job is to leave water nowhere to enter, which is why the seams are welded and why the substrate has to be sound before the sheet goes down.