Vinyl Membrane Decks (Duradek) in Canmore & the Bow Valley

What this is

A vinyl membrane deck is a sheet of PVC-based waterproof membrane heat-welded into a single seamless surface and installed over a continuous plywood substrate. Duradek (60-mil membrane, 20-year warranty) and DeckRite (50-mil, 15-year warranty) are the two systems we install. Unlike wood or composite decking - which is many separate boards with gaps water passes through - a membrane deck is one continuous waterproof surface. That makes it the only correct choice when there is something underneath the deck that needs to stay dry: a garage, a basement walkout, a covered porch, or the living space below a rooftop deck.

Who this is for

• Owners of rooftop decks or upper-storey decks over a garage, sunroom, or finished space below
• Second-home buyers in Spring Creek or Eagle Terrace where the deck overhangs the parking pad or storage
• Hot tub deck owners who want a sealed surface that won't trap moisture between boards
• Homeowners who want a low-maintenance, easy-to-clean entertaining surface (sweep, hose, done)
• Anyone replacing a failed traditional deck over living space where water damage is already showing inside

Our process

1. Free site visit, substrate assessment, and slope check. We confirm whether your existing substructure can accept a membrane install or whether a sleeper system is needed for proper drainage.
2. Fixed-price quote with system specified. Duradek Legacy, Duradek Ultra, or DeckRite - quoted with your colour/pattern selection from physical samples.
3. Permits & engineering. Town of Canmore (or Parks Canada for Banff) permits. Rooftop and over-living-space decks require structural engineering review.
4. Substrate prep. 5/8" T&G plywood deck sheathing fastened on 6" perimeter / 12" field pattern, all seams gapped 1/8" for expansion, drainage slope verified to 1:50 minimum (we shoot for 1:25).
5. Membrane install. Sheet membrane rolled, contact-adhesive applied, seams heat-welded with a hot-air welder, perimeter terminations counter-flashed and sealed. Drip edges, scuppers, and post penetrations detailed per manufacturer spec.
6. Flood test & warranty registration. 24-hour water test to confirm zero leaks, then warranty registered in your name and full documentation delivered.

System options

Colour options: 7 standard Duradek colourways (Stonebridge, Tundra, Driftwood, Mosaic, Mountain Stone, Tweed, and solid greys). Stone-pattern colourways hide pollen, dust, and water spots better than solids - our most-specified for Bow Valley properties.

Pricing factors

• Installed range: $90–130 /sq ft for a complete Duradek deck including substructure, plywood substrate, membrane, and basic perimeter railing
• Substructure complexity: Rooftop and over-living-space installs add $15–25 /sq ft for engineered slope, additional structural reinforcement, and warranty interface with the roofing system
• Colour/pattern selection: Premium stone-pattern Duradek colourways add ~$3–5 /sq ft over standard solid colours
• Penetrations & detailing: Each post penetration, drain, or scupper adds $150–300 in labour for proper flashing and weld detailing
• Railing system: Aluminum or glass railings preferred - anything fastened through the membrane requires special detailing (we use surface-mount where possible)

Bow Valley local context

Duradek is the standard answer in the Bow Valley for any deck over living space, and the reason is freeze-thaw. A wood or composite deck with gapped boards lets snowmelt through to the structure below - most of the year that's fine because the structure dries. But during shoulder seasons (March–April, October–November) when daytime melt is followed by hard overnight freeze, water that has soaked into framing, sheathing, or top-floor finishes freezes, expands, and damages everything it touched. A Duradek membrane shuts that pathway down completely. We've replaced enough water-damaged sub-decks under Canmore rooftop spaces to know the cost of getting this wrong.

For structural design, the Town of Canmore's 2.5 kPa ground snow load still governs and Duradek decks are framed on 12" o.c. PT joists the same as any other deck - the membrane just adds a continuous plywood substrate and the waterproof layer. Slope is the critical install detail at our elevation: minimum 1:50 (2%), but we build to 1:25 (4%) wherever feasible because Canmore's freeze-thaw turns temporary ponding into ice that stresses seam welds. Rooftop installs require coordination with the existing roofing warranty - we work with your roofer (or recommend one) so neither system voids the other. Permits are required for any deck install over 0.6 m off grade, and any deck over living space requires engineered drawings regardless of height. Town of Canmore Planning turnaround averages 14 business days; Parks Canada Banff approvals run 3–6 weeks.

Why choose Canmore Deck Builders

Certified Duradek installers

Duradek warranties are installer-dependent - improperly welded seams or wrong flashing detailing voids the warranty entirely. We're certified Duradek installers with current credentials and follow manufacturer spec on every weld, every termination, every penetration. The 20-year warranty actually means 20 years.

Certified Duradek installer · current credentials, full warranty pass-through

Substrate discipline before membrane goes on

The membrane is only as good as the plywood under it. We use 5/8" T&G plywood (never OSB on a deck), fastened on 6" perimeter / 12" field pattern, with 1/8" expansion gaps at every sheet edge. We confirm slope with a laser at every quadrant of the deck before membrane goes down. About one in three "overlay over existing deck" inquiries we get end up needing substrate rebuild - we tell you up front rather than weld over a problem.

5/8" T&G plywood minimum substrate spec on every install

24-hour flood test before handover

Every Duradek install we complete is flood-tested before sign-off. We dam the drains, fill to ~25 mm depth, and leave it 24 hours. Any leak shows up before we leave the site. We've never had a callback for a leak that escaped this test.

0 leak callbacks on Duradek installs since 2017 · internal data