Is it a problem to have poly on both sides?

Yes. Two barriers trap moisture between them with no direction to dry. It is a real mistake we still find in renovated Canora walls, and it stays invisible until the damage shows.

Will this stop water coming through my basement wall?

No, and installing it would hide the evidence. Water coming through a wall is a drainage and waterproofing problem. Vapour control manages moisture in the air, not liquid water, and we will say so rather than board over it.

Does it matter where the sheets overlap?

Yes. A lap must land on solid framing and be sealed with acoustical sealant compressed between layers. An unsupported lap taped across a cavity flexes with pressure changes and works loose.

Can I add poly over insulation that already has a facing?

Usually no. Two retarders leave any moisture that gets in with no direction to dry. We check what is already in the wall before adding to it rather than assuming the cavity is bare.

What if there is already a vapour barrier in the wall?

We tie into it, and we check whether there is a second one somewhere that would trap moisture between the two. Older Canora renovations quite often have both, and finding that before boarding is worth the hour.

Vapour Barrier Installation Canora Edmonton | 6 Mil Poly

Poly and air sealing in Canora before the board goes on

Alberta winters put a large vapour drive from inside to outside, so the barrier belongs on the warm side of the insulation. Getting the position right matters as much as getting it sealed: a second barrier on the cold side traps moisture in the assembly with no way to dry.

Left ready for inspection before boarding
Window and door returns detailed properly
Electrical boxes poly-hatted and sealed
Seams lapped at framing and sealed, not just taped
Rim joists air-sealed before insulating
Poly on the warm side of the insulation

Where poly is the wrong choice

Not every assembly wants it

Some Canora walls, such as an insulated concrete basement or an assembly with exterior rigid insulation, are designed to dry inward, and a full poly layer stops that.

How we approach it

We look at the whole assembly rather than defaulting to poly because it is what is usually done. Where a smart or variable-permeance membrane is the right call, we say so.

Canora drywall in context

About Canora

The Canora school was opened in 1949, and the neighbourhood became known by the school's name.

What we see in Canora

In Canora the drywall work is plaster and lath repair, popcorn and stipple ceiling removal, careful patching into original surfaces. We confirm what your home actually needs on site, in writing, before anything starts.

Electrical boxes, the usual failure point

A hole in the plane

Every outlet and switch in an Canora exterior wall is a cut in the poly. Left unsealed it is a direct path for moist air into the cavity, and the boxes are usually the coldest spot on the wall.

Poly hats and sealant

Boxes get a poly hat or an air-sealed box, and the poly is sealed to it rather than simply cut around. It is a small detail repeated dozens of times, which is exactly why it gets skipped.

What a vapour barrier is not

It is not an air barrier by itself

Poly slows vapour diffusion. Sealed properly it also slows air, and unsealed it does very little of either. The sealing is what turns a sheet of plastic into a working assembly.

It is not a damp-proofing fix

If a Canora basement has water coming through the wall, vapour control is not the answer and installing it will hide the evidence. That is a drainage and waterproofing problem, and we will say so rather than board over it.

Top plates, bottom plates and the perimeter

The edges do the leaking

The continuous joints at the top and bottom of an Canora wall are longer than every box and lap put together, and they are the easiest to seal well or badly.

What good looks like

Sealant on the plate, poly laid into it and compressed by the framing or the board above, carried around corners rather than cut and butted at every change of direction.

Windows, doors and the returns around them

Where the detail gets fiddly

The return between a window frame and the wall in Canora is awkward, tight, and often left as a torn edge tucked behind trim.

Why it matters

It is also a cold junction where condensation shows first, usually as staining or mould at the reveal. The poly is cut to fit, sealed to the frame and supported, rather than folded and hoped for.

Poly against smart membranes

Two approaches

Standard 6-mil poly is the common choice in Canora and works when it is continuous and sealed. A variable-permeance membrane tightens in winter and opens in summer, giving the assembly a drying path in both directions.

When it is worth the difference

Most straightforward walls are fine with poly. Retrofits, assemblies that cannot be fully sealed and some basement details benefit from a membrane. We say which we would use and why rather than defaulting.

How it works

Simple, clean, on schedule — Vapour Barrier Installation in Canora Edmonton

Free quote

We come out to your Canora Edmonton property, take a real look at the vapour barrier installation, and hand you a fixed price on the spot — no guessing, no vague ballpark. Every vapour barrier installation quote in Canora Edmonton starts with an honest, on-site assessment.

Book a day

We pick a day that works for your schedule and show up on time, ready to start the vapour barrier installation in Canora Edmonton. No back-and-forth rescheduling — once it's booked, our team is there.

The work

We keep the dust under control and protect your Canora Edmonton home while we finish the vapour barrier installation to a clean, paint-ready standard. Floors covered, doors sealed off, and the site left tidy at the end of every day.

Walk it with you

We don't pack up till you've walked the finished vapour barrier installation with us and you're happy with the result in Canora Edmonton. If anything needs a second look, we handle it before we call the job done.

Reviews

Rated by Edmonton Homeowners

★ ★ ★ ★ ★

Emplastrum Drywall is the vapour barrier installation contractor Canora Edmonton trusts for repair, restoration and finishing — rated on Google by Edmonton homeowners.

Read the reviews, or leave your own after your vapour barrier installation project in Canora Edmonton.

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FAQ — Vapour Barrier Installation Canora Edmonton

Vapour Barrier Installation Canora Edmonton: your questions answered

Is it a problem to have poly on both sides?: Yes. Two barriers trap moisture between them with no direction to dry. It is a real mistake we still find in renovated Canora walls, and it stays invisible until the damage shows.
Will this stop water coming through my basement wall?: No, and installing it would hide the evidence. Water coming through a wall is a drainage and waterproofing problem. Vapour control manages moisture in the air, not liquid water, and we will say so rather than board over it.
Is the vapour barrier the same as an air barrier?: Not by itself. Poly slows vapour diffusion; sealed properly it also slows air, and unsealed it does very little of either. The sealing is what turns a sheet of plastic into a working assembly.
Does it matter where the sheets overlap?: Yes. A lap must land on solid framing and be sealed with acoustical sealant compressed between layers. An unsupported lap taped across a cavity flexes with pressure changes and works loose.
Can I add poly over insulation that already has a facing?: Usually no. Two retarders leave any moisture that gets in with no direction to dry. We check what is already in the wall before adding to it rather than assuming the cavity is bare.
What if there is already a vapour barrier in the wall?: We tie into it, and we check whether there is a second one somewhere that would trap moisture between the two. Older Canora renovations quite often have both, and finding that before boarding is worth the hour.

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Vapour Barrier Installation Canora Edmonton

Poly and air sealing in Canora before the board goes on