Duradek is a sheet vinyl waterproofing membrane for decks, balconies and rooftop patios. It is rolled out over plywood as one continuous sheet, the seams are heat-welded shut, and the edges are detailed into the walls and drains around it. The result is a surface you walk on that is also a roof — which is the whole point of it.
It has been made in Canada since the 1970s and it is common across the Lower Mainland for one obvious reason: a lot of houses here have a deck sitting directly on top of a garage, a suite or a living room, and 1,150 mm of rain a year has to go somewhere other than through the ceiling.
What is Duradek made of?
Reinforced PVC — polyvinyl chloride. The sheet is built in layers:
| Layer | What it does |
|---|---|
| Printed and textured wear layer | The surface you see and walk on. The texture is what gives it grip when wet. |
| PVC core | The waterproofing. This is the part doing the actual work. |
| Backing | Bonds the sheet to the plywood. Duradek’s premium Ultra line uses a woven polyester backing; thinner products use a non-woven backing. |
Membranes are specified by thickness in mils (thousandths of an inch). The common residential options are 45 mil and 60 mil, and the thickness tracks directly to the warranty:
| Product | Waterproofing warranty |
|---|---|
| Ultra 60 mil, woven backed | 15 years |
| Non-woven backed 60 mil | 10 years |
| 45 mil | 5 years |
Duradek’s warranty is non-prorated and transfers with the property. We went into what those terms actually mean in practice in how long does Duradek last.
How is Duradek installed?
Understanding the install is the fastest way to understand why some vinyl decks last thirty years and some leak in three. It is roughly five steps:
- The substrate goes down first. Solid exterior-grade plywood, sloped so water runs to a drain or over the edge. Vinyl cannot be laid over spaced deck boards, and it cannot fix a deck that does not drain — a flat substrate produces a flat vinyl deck holding puddles.
- The sheet is laid out and bonded. Adhesive over the whole surface, worked out so there is no air trapped underneath.
- Seams are heat-welded. Where two sheets meet, they are fused into one piece. Welded, not glued and not taped. This is the difference between a membrane and a tarp.
- The perimeter is detailed. The membrane turns up the wall behind the siding, laps into the building envelope, and terminates at drains, scuppers and door thresholds. This is the part that decides whether the deck works.
- Penetrations are detailed. Every railing post that goes through the surface is a deliberate hole in the waterproofing and has to be treated as one.
Steps four and five are where installations go wrong, and they are invisible once the job is finished — which is exactly why the installer matters more than the brand on the roll.
Where does Duradek belong — and where does it not?
The single question that decides it: does anything under this deck need to stay dry?
| Situation | Right surface |
|---|---|
| Deck over a garage, suite or living space | Vinyl membrane — you are building a roof |
| Balcony that forms the ceiling below | Vinyl membrane |
| Rooftop patio | Vinyl membrane |
| Ground-level deck, nothing underneath | Composite or wood boards — they drain freely and cost less to keep |
| Elevated deck over open yard | Usually boards, unless you want dry storage below |
| Existing deck with a soft or rotted substrate | Neither yet — the structure gets fixed first |
Vinyl over a ground-level deck with open air below is not wrong, it is just paying for waterproofing that nothing needs and accepting a sealed surface where a drained one would be easier to live with. We laid out the full decision in Duradek vs composite decking.
Is Duradek the same as a rubber roof or torch-on?
No, and the difference is what you walk on. Torch-on and liquid-applied membranes are roofing systems — they waterproof, then generally need pavers, ballast or a separate wear surface on top before anyone uses the space. Duradek waterproofs and finishes in one product. That is why it turns up on residential decks and balconies rather than on flat roofs nobody walks on.
What goes wrong with Duradek?
The honest list, in the order we find them:
- Seams that were not properly welded. A seam you can lift with a fingernail is a seam water is already getting into.
- Perimeter and wall flashings. If the membrane was cut short at the wall and caulked rather than tucked into the envelope, the deck is directing water behind the siding.
- Railing posts through the membrane with no detail. A hole in the waterproofing pointed at the rim joist. This is the most common single failure on decks over living space — see deck railings in Vancouver.
- Not enough slope. Standing water finds every weakness, every rainfall, all winter.
- A substrate that was already going. New membrane over soft plywood buys a season and costs the job twice — the same rule that governs deck repair generally.
Notice that none of those is the vinyl. Practically every “Duradek problem” is a workmanship problem wearing the product’s name.
Why certified installation matters here more than usual
The manufacturer warranty on Duradek is only available through authorized installers. An uncertified install can use the correct membrane and still leave you with no manufacturer coverage at all — which you discover in year six, when it matters.
VS Deck & Rail is a certified Duradek installer. That means the membrane comes through the proper supply channel, the installation gets registered, and the warranty is real rather than assumed. We install and replace vinyl decks across Metro Vancouver — Vancouver, North Vancouver, Burnaby, Richmond, Surrey and Delta.
If you are weighing vinyl against boards, or you have an existing vinyl deck you are unsure about, request a free quote and we will look at the substrate before we talk about the surface. Day-to-day care is covered in how to clean Duradek.
Frequently Asked Questions
What is Duradek?
Duradek is a brand of sheet vinyl waterproofing membrane made for decks, balconies and rooftop patios. It is rolled out over a plywood substrate as a continuous sheet, the seams are heat-welded so there are no joints for water to pass through, and the edges are detailed into the surrounding walls and drains. The result is a walking surface that is also a waterproof roof. It has been manufactured in Canada since the 1970s.
What is Duradek made of?
It is a reinforced PVC (polyvinyl chloride) membrane. The sheet has a printed and textured wear layer on top for grip and appearance, a PVC core that does the waterproofing, and a backing that bonds to the plywood below — Duradek’s premium Ultra line uses a woven polyester backing, and thinner products use a non-woven backing. Membranes are sold by thickness in mils, typically 45 mil or 60 mil.
Where should Duradek be used and where should it not?
Use it wherever something under the deck has to stay dry: a deck over a garage, over living space, over a suite, or a balcony that forms someone’s ceiling. Do not use it as a default surface on a ground-level deck with nothing underneath — there, spaced composite or wood boards drain freely, cost less to maintain and are easier to repair. Vinyl also needs a properly sloped, solid plywood substrate; it cannot be laid over spaced boards.
Is Duradek the same as a rubber roof or a torch-on membrane?
No. Torch-on and liquid-applied membranes are roofing systems that usually need a separate wear surface or ballast on top. Duradek is a single product that waterproofs and provides the finished walking surface at the same time, which is why it is used on residential decks and balconies rather than flat roofs you never walk on.
What are the common problems with Duradek?
Almost all of them are installation problems rather than product problems. Seams that were not welded correctly, perimeter and wall flashings that were not tucked into the building envelope, railing posts drilled straight through the membrane without a detail, and insufficient slope so water sits instead of draining. The membrane in the middle of the field very rarely fails on its own.
Does Duradek have to be installed by a certified installer?
The manufacturer warranty is only available through authorized installers, so an uncertified installation leaves you with no manufacturer coverage even if the correct product was used. VS Deck & Rail is a certified Duradek installer, which means the membrane is supplied through the proper channel and the installation is registered for warranty.
