"Waterproof decking" means two different things. If there's living space below your deck, you need a fully waterproof membrane system that sheds every drop and keeps that space dry. For open decks, pools and rooftop pedestal builds, you need a moisture-stable board that won't soak up water or warp — like Tarimatec stone composite.
Short answer: "Waterproof decking" means two different things. If there's living space below your deck, you need a fully waterproof membrane system that sheds every drop and keeps that space dry. For open decks, pools and rooftop pedestal builds, you need a moisture-stable board that won't soak up water or warp — like Tarimatec stone composite.
You search "waterproof decking Canada" and you meet a wall of vinyl: Duradek, Tufdek, Econodek. They're good products — but they answer only half the question, and the half they answer is the one most homeowners don't actually have. We wrote this to untangle that confusion, define what "waterproof" really means for a Canadian deck, and show you exactly which system you need based on the one thing the search results keep ignoring: what's underneath your boards.
We're Zinodeck, the exclusive Canadian distributor of Tarimatec Ecofiber stone composite decking — a European-engineered board, made in Paterna, Valencia, Spain by Plásticos Viters S.A. and selected specifically for Canadian freeze-thaw, UV and moisture conditions. We sell a board, not a membrane, so we'll be straight with you about where each one belongs — including the jobs our board can't do.
Before you buy anything, get this one idea straight, because it decides your whole project. When you say you want "waterproof decking," you're really after one of two different goals — and the right product depends entirely on which one is yours.
Put bluntly: a membrane keeps water off the space below. A moisture-stable board keeps water out of the board itself. They solve different problems, and the marketing word "waterproof" gets stretched across both — which is exactly why the search results are such a mess.
We see the consequences of that confusion most clearly on a second-storey deck in midtown Toronto, where the family wants a dry patio set with a sofa and a TV on the ground level below. The boards they pick barely matter to that goal. Water sheets off any board and straight down through the gaps onto whatever's underneath — so the dry patio they're picturing lives or dies on the membrane and drainage beneath the deck, not on the plank they fell in love with in a showroom.
Rule of thumb for Canada: if you can stand under your deck and stay dry, you need a waterproof membrane. If the only thing under your deck is open air, joists or gravel, you need a moisture-stable board — not a membrane.
Look down before you look at boards. If there's something under your deck that has to stay dry, your real product isn't a plank at all — it's a fully waterproof membrane (a vinyl/PVC sheet, a liquid-applied system, or an under-deck drainage ceiling). In our experience these are the Canadian situations that demand one:
Picture a walkout in the Kawarthas through spring melt. The snow load on the deck above lets go all at once, and the family wants to store the canoe and the patio set dry in the space beneath. On a build like that the membrane is non-negotiable, and a board alone — composite, PVC or otherwise — will never do the job. The board may sit on top of the membrane, on sleepers or pedestals, but the membrane is the thing keeping that meltwater out of the space below.
Now flip it. If you look under your deck and see open air, joists or gravel, you've been worrying about the wrong product. You don't need a membrane — you need a board that ignores water. A moisture-stable board is the correct, more economical, better-draining choice when:
This is precisely the role Tarimatec stone composite is built for. Think of a Vancouver poolside deck through the rainy season — months of runoff and standing puddles that would have a wood-fibre board wicking and swelling at every cut end. Tarimatec's dense, mineral-rich core doesn't soak that water up, so it won't swell, cup or rot, and it shrugs off the freeze-thaw movement that destroys absorbent materials over a Canadian winter. For wet zones like that, we'd point you to the Surco anti-slip finish — a linear-groove texture purpose-made for poolside, rooftop and rainy-climate decks.
If you're weighing your options, there are three honest categories on the table, and they aren't interchangeable. We won't pretend our board does what a membrane does — vinyl membranes, PVC boards, and stone composite boards each win in a different situation. Here's how we lay them out for the homeowners and builders we talk to.
| Option | What it is | Truly waterproof system? | Best for | Watch-outs |
|---|---|---|---|---|
| Vinyl / PVC membrane (Duradek, Tufdek, Econodek, etc.) | A continuous PVC sheet heat-welded over a plywood substrate; the surface is the waterproofing. | Yes — sheds 100% of water | Decks over living space, balconies, walkouts, dry space below | Sheet look underfoot; seams must be welded perfectly; can feel hot and plasticky; not a "real board" aesthetic |
| PVC (cellular) boards | 100% plastic boards with no organic filler; individual planks, not a sealed sheet. | No — water drains through gaps (board is non-absorbent) | Open decks, pool surrounds where a synthetic board look is wanted | Can be the priciest board tier; lighter, more thermal movement; some find the look less natural |
| Stone composite boards (Tarimatec Ecofiber) | ~50% rice husk + recycled ground calcite in a PVC matrix; a dense mineral composite, distinct from wood-plastic composite (WPC). | No — water drains through gaps (dense core does not absorb) | Open decks, pools, docks, rooftop pedestal builds; freeze-thaw and UV-heavy sites | Not a membrane — cannot waterproof space below on its own; full boards are quote-direct |
| Standard wood-plastic composite (WPC) | Wood flour + recycled plastic; capped or uncapped planks. | No — and the wood fibre can absorb water if the cap is breached | Budget-conscious open decks | Wood fibre means swelling/mould risk at cut ends or scratches; more freeze-thaw movement |
Notice the pattern: only the membrane is a "waterproof system." Every board option — PVC, stone composite, WPC — relies on water draining between the boards. Among the boards, what separates them is how the material itself handles water, which is where stone composite pulls ahead of conventional WPC. If your real question is the head-to-head between cellular PVC and composite, we kept that comparison out of this guide on purpose and put it where it belongs — our breakdown of composite decking vs PVC.
If you're leaning toward a board, here's the thing that should drive the choice: how the material itself behaves when water sits on it through a Canadian year. Standard composite decking is wood-plastic composite — wood flour bound in recycled plastic. Even capped WPC has an exposed core at every cut end and screw hole, and if that wood fibre meets standing water through a scratch or an uncapped edge, it can wick moisture, swell and grow mould. Over freeze-thaw cycles, absorbed water expands as it freezes — and that's what drives the cupping, splitting and fastener pop-out we get called out to look at on absorbent boards.
Tarimatec is a different category. Its core is roughly 50% rice husk — an agricultural by-product — blended with recycled mineral content (ground calcite) in a PVC matrix. The result is a dense, mineral-rich board with very low water absorption and minimal dimensional movement. Picture a Calgary deck riding a January chinook: the surface thaws in the afternoon sun and refreezes by nightfall, the freeze-thaw swing that quietly tears absorbent boards apart. In Canadian terms, here's what that dense core buys you:
You can read the full third-party documentation on our EPD and sustainability page. And if you're weighing materials more broadly, our guide to the best composite decking in Canada puts stone composite next to the major WPC brands on exactly this moisture question.
If you're a builder, developer or condo corporation, this is where the membrane-versus-board distinction stops being trivia and becomes system design — and it's the highest-value scenario we work on. Get the layering right and the deck above stays dry below for decades; get it wrong and you're tearing it out.
On a rooftop, the waterproofing is the roof assembly — a tested membrane installed by the roofing trade. The deck you walk on sits above it. The cleanest way to build that walking surface is a pedestal (adjustable-height) system: pedestals rest on the membrane, level out the roof's drainage slope, and hold the boards or tiles on a continuous air gap. Water drains freely beneath, the membrane is never penetrated, and a failed area can be lifted and reinstated without tearing out the whole deck.
Picture a downtown Toronto condo terrace over occupied units: wind-driven rain and winter snowmelt pond on that flat roof, and the slope built into the pedestals is what carries it to the drains instead of letting it sit. Stone composite suits this build because it's dimensionally stable across the wild temperature swing a dark rooftop sees — well below freezing in winter, baking in direct summer sun — it doesn't absorb that ponding water and snowmelt, and it comes in both plank and tile formats that drop onto pedestals. For specifiers, the EPD and ISO documentation supports green-building and LEED submissions on condo and mixed-use projects. The roles, kept straight:
Builders and contractors specifying rooftop or balcony decks at volume can reach us for trade pricing and technical data through the Zinodeck trade and dealer program.
Here's where getting the category wrong gets expensive. Because "waterproof decking" spans two product types, your budgets aren't directly comparable — you're pricing either a membrane system or a board, and sometimes both stacked together.
The two big budgeting mistakes we watch people make: paying for a full membrane on an open deck off a Muskoka cottage that never needed one — the rain was always going to drain through to the gravel — and, the costlier error, skipping the membrane on a deck-over-living-space and trying to make boards alone do a waterproofing job they physically cannot do. Get the category right first, then price it.
For a board-level estimate on your specific square footage, run the numbers through the Zinodeck CAD cost calculator. Tarimatec sample boards can be ordered online so you can feel the density and the Surco texture before you commit; full boards are quote-direct.
If you take one workflow from this guide, take this one. Stand on your deck site, look down first, then walk these four questions in order:
If you're cross-shopping premium brands while you decide, our comparison of the best Trex alternatives in Canada covers how stone composite stacks up against the North American composite leaders on moisture and freeze-thaw performance.
There is no single best — it depends on what is below the deck. For a deck over living space, the best "waterproof decking" is a tested vinyl/PVC membrane system (Duradek, Tufdek and similar), because only a continuous sealed membrane keeps the space underneath dry. For an open deck, pool surround or rooftop pedestal build, the best choice is a dense, non-absorbent, freeze-thaw-stable board such as Tarimatec stone composite, ideally in the anti-slip Surco finish for wet zones.
Individual deck boards installed with the normal expansion gaps always let water drain between them — that is by design, so the deck dries and does not pond. The only way to stop water passing through the surface entirely is a continuous waterproof membrane (a vinyl/PVC sheet) or a sealed under-deck drainage ceiling. If your goal is a dry space below, you need that membrane system; if your goal is simply a board that does not absorb water and warp, a non-absorbent board like stone composite or cellular PVC delivers that without a membrane.
Composite decking is better described as water-resistant, not waterproof. Standard wood-plastic composite (WPC) contains wood fibre that can absorb moisture at cut ends or scratches, leading to swelling or mould. Tarimatec stone composite is denser and mineral-based — roughly 50% rice husk plus recycled calcite in a PVC matrix — so it does not soak up water or warp and handles freeze-thaw far better. But no composite board is a waterproofing system on its own: water still drains between the boards, so a deck over living space still needs a membrane underneath.
Only if there is living or usable space below the deck that must stay dry — for example a rooftop terrace over a condo unit, a balcony over a finished room, or a walkout you want to use as covered space. In that case the membrane (or roof assembly) does the waterproofing and the composite boards sit on top, often on sleepers or pedestals. For an ordinary open deck with air or gravel beneath, you do not need a membrane; you just need a moisture-stable board.
For pools and rooftops, you want a board that ignores standing water, resists freeze-thaw movement, stays cooler in direct sun and grips when wet. Tarimatec stone composite in the Surco anti-slip finish is built for exactly these conditions, and it comes in plank and tile formats that drop onto rooftop pedestal systems. On a rooftop, remember the roof membrane provides the actual waterproofing; the stone composite is the durable, slip-rated surface above it.
Yes. Tarimatec is European-engineered (made in Spain by Plásticos Viters S.A.) and selected for Canadian weather, and Zinodeck (West Nova Group Ltd., Vaughan ON) is its exclusive Canadian distributor. It is offered nationally across 31 colours in three collections — Chromatic, Wood and Ethnic — and three finishes — Nature, Tecno and Surco. Samples ship from our online store and full boards are quoted directly.
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