Vapour Barrier Installation University of Alberta Farm Edmonton

Poly and air sealing in University of Alberta Farm 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.

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

Vapour Barrier Installation University of Alberta Farm Edmonton

Where the barrier meets the ceiling and the floor

University of Alberta Farm drywall in context

Renovations, and meeting an existing barrier

Bathrooms, kitchens and the wet rooms

The parts an inspector looks at first

Electrical boxes, the usual failure point

Laps, and the framing member behind them

Simple, clean, on schedule — Vapour Barrier Installation in University Of Alberta Farm Edmonton

Vapour Barrier Installation University of Alberta Farm Edmonton: your questions answered

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.

Is a basement wall done the same way as an upstairs wall?

No. A basement wall can take moisture from the ground too, so poly detailed like an above-grade wall can trap moisture against the concrete. The insulation is held off the concrete so the wall can dry, with vapour control on the warm side.

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 University of Alberta Farm walls, and it stays invisible until the damage shows.

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.

Why is there staining around my window reveals?

Usually the vapour barrier return at the window was torn or tucked rather than sealed. It is a cold junction, so condensation shows there first — often as staining or mould at the reveal.

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.