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.

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 Northmount renovations quite often have both, and finding that before boarding is worth the hour.

Is poly always the right answer?

No. Some assemblies, such as insulated concrete basements or walls with exterior rigid insulation, are designed to dry inward, and poly stops that. We look at the whole assembly rather than defaulting.

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.

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.

Vapour Barrier Installation Northmount Edmonton | 6 Mil Poly

Poly and air sealing in Northmount before the board goes on

A vapour barrier only works as a continuous plane. In Northmount the failures are almost never the sheet itself — they are the electrical boxes, the top and bottom plates, the window returns and the penetrations, where the poly is cut and not resealed.

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

Windows, doors and the returns around them

Where the detail gets fiddly

The return between a window frame and the wall in Northmount 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.

Northmount drywall in context

About Northmount

Residential land accounts for almost 70 percent of Northmount.

What we see in Northmount

In Northmount 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 Northmount 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.

Warm side, always

The one rule everything else follows

The barrier goes on the heated side of the insulation. In an Northmount climate that is the room side of an exterior wall.

Why position decides everything

Put it on the cold side and you have placed a moisture stop exactly where indoor humidity will condense against it, inside the wall, where nothing dries and nothing is visible until the damage is done.

Basement walls, where the rules change

Concrete complicates it

A Northmount basement wall can take moisture from the ground as well as from the room. That is why a poly barrier detailed the way it is on an above-grade wall can trap moisture against the concrete instead of keeping it out.

How the assembly is built

Rigid insulation or a framed cavity held off the concrete gives the wall a way to dry, with vapour control on the warm side of the insulation. Getting that order wrong is the most common reason a finished Northmount basement smells musty.

The rim joist and the bottom plate

Two cold junctions

In an Northmount basement the rim joist and the bottom plate against concrete are where warm air meets cold most directly. Both need sealing before insulation, not after.

Sequencing

Once the insulation and poly are on, neither can be reached without pulling the wall apart. We deal with them first, and we would rather flag a problem there at the quote than discover it behind a finished wall.

Bathrooms, kitchens and the wet rooms

More moisture, same rules

A Northmount bathroom pushes far more vapour into the wall than a bedroom. The barrier is not different, but the consequences of a gap are larger and show up faster.

Fans and penetrations

The fan housing, the duct and any pot lights all pierce the plane in the wettest room in the house. Those are sealed rather than trimmed around, and we check that the fan actually vents outside rather than into the attic.

How it works

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

Free quote

We come out to your Northmount 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 Northmount 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 Northmount 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 Northmount 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 Northmount 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 Northmount 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 Northmount Edmonton.

Read our reviews on Google

FAQ — Vapour Barrier Installation Northmount Edmonton

Vapour Barrier Installation Northmount Edmonton: your questions answered

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.
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 Northmount renovations quite often have both, and finding that before boarding is worth the hour.
Is poly always the right answer?: No. Some assemblies, such as insulated concrete basements or walls with exterior rigid insulation, are designed to dry inward, and poly stops that. We look at the whole assembly rather than defaulting.
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.
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.

Get Your Free Drywall Quote

Tell us about your project — we’ll get right back to you, 7 days a week. Prefer to call? (403) 829-8702.

Full Name / Company

Phone Number

Email Address

Area

Service Needed

I agree to be contacted by Emplastrum Drywall about my project by phone, text, or email.

No obligation. We never share your information.

📐 Plan Your Project

Estimate Your Insulation

📐 Materials Calculator

How much do you need?

Enter your room size for a quick materials estimate.

Room length (ft)Room width (ft)Ceiling height (ft)Number of rooms Include ceilingSheet sizeCoats of paintCavity depthFraming spacingInsulation already there (in)Top up to (in)Stud spacingDoorsWindowsWaste allowance (%)

Estimate only — rounded up, based on standard coverage rates (drywall +10% waste; paint ~350 sq ft per gallon per coat; batt bundles by cavity depth, less a framing factor; studs at your chosen spacing plus waste). Product coverage varies by brand — confirm quantities before buying. Ask us about the right R-value for your project.

Rather we handle it? Get a free estimate →

Vapour Barrier Installation Northmount Edmonton

Poly and air sealing in Northmount before the board goes on