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 Westwood walls, and it stays invisible until the damage shows.

Do the electrical boxes really need sealing?

They are the most common failure point. Every outlet in an exterior wall is a cut in the plane, and unsealed it is a direct path for moist air into the cavity at the coldest part of the wall.

Which side does the vapour barrier go on?

The warm side of the insulation. Through an Alberta winter moisture pushes outward from the heated space, and the barrier stops it before it reaches a cold surface where it can condense.

Will this pass inspection?

It is built to what the code asks for on your permit, and we leave it visible and sequence to your inspection date rather than boarding ahead. If an inspector raises something, we want the note directly so it is fixed from the actual reason.

What about outlets on exterior walls?

Each one is a deliberate hole. They need poly hats or airtight boxes sealed to the sheet. Taping poly to the front of an ordinary box does not last once board is fastened over it, and it is the most common leak we find.

Vapour Barrier Installation Westwood Edmonton | 6 Mil Poly

Vapour barrier in Westwood, sealed as a continuous plane

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

Poly against smart membranes

Two approaches

Standard 6-mil poly is the common choice in Westwood 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.

Westwood drywall in context

About Westwood

The character of Westwood has changed considerably in the second half of the 20th century.

What we see in Westwood

In Westwood 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.

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 Westwood 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 Westwood 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.

Where the barrier meets the ceiling and the floor

The two continuous edges

A Westwood wall barrier has to be sealed at the top plate and the bottom plate. Left loose, warm air simply goes over or under a perfectly installed sheet.

Cathedral and vaulted areas

Where a wall runs into a vaulted ceiling the junction is awkward and often skipped. It is also the warmest, wettest point in the room because that is where the air collects. It gets detailed properly or the rest of the sheet is decorative.

Electrical boxes, the usual failure point

A hole in the plane

Every outlet and switch in an Westwood 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.

Laps, and the framing member behind them

Where sheets meet

A lap needs to land on solid framing and be sealed with acoustical sealant compressed between the layers, not taped in mid-air across a cavity.

Why it fails otherwise

An unsupported lap flexes with pressure changes and the seal works loose. In an Westwood build the sheets are planned so that laps fall on studs rather than wherever the roll ran out.

How it works

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

Free quote

We come out to your Westwood 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 Westwood 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 Westwood 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 Westwood 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 Westwood 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 Westwood 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 Westwood Edmonton.

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FAQ — Vapour Barrier Installation Westwood Edmonton

Vapour Barrier Installation Westwood 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 Westwood walls, and it stays invisible until the damage shows.
Do the electrical boxes really need sealing?: They are the most common failure point. Every outlet in an exterior wall is a cut in the plane, and unsealed it is a direct path for moist air into the cavity at the coldest part of the wall.
Which side does the vapour barrier go on?: The warm side of the insulation. Through an Alberta winter moisture pushes outward from the heated space, and the barrier stops it before it reaches a cold surface where it can condense.
Will this pass inspection?: It is built to what the code asks for on your permit, and we leave it visible and sequence to your inspection date rather than boarding ahead. If an inspector raises something, we want the note directly so it is fixed from the actual reason.
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.
What about outlets on exterior walls?: Each one is a deliberate hole. They need poly hats or airtight boxes sealed to the sheet. Taping poly to the front of an ordinary box does not last once board is fastened over it, and it is the most common leak we find.

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Vapour Barrier Installation Westwood Edmonton

Vapour barrier in Westwood, sealed as a continuous plane