Vapour Barrier Installation Kinglet Gardens Edmonton

Vapour barrier in Kinglet Gardens, 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.

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

Vapour Barrier Installation Kinglet Gardens Edmonton

Seams belong on framing

Kinglet Gardens drywall in context

Electrical boxes, the usual failure point

Basement walls, where the rules change

Sealing at the electrical boxes

Laps, and the framing member behind them

Windows, doors and the returns around them

Simple, clean, on schedule — Vapour Barrier Installation in Kinglet Gardens Edmonton

Vapour Barrier Installation Kinglet Gardens Edmonton: your questions answered

Is a bathroom done differently?

Same rules, larger consequences. A bathroom pushes far more vapour into the wall, so a gap shows up faster. The fan housing and duct are sealed rather than trimmed around, and we check the fan vents outside rather than into the attic.

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.

Should I use poly or a smart membrane?

Most straightforward Kinglet Gardens walls are fine with 6-mil poly, continuous and sealed. A variable-permeance membrane is worth it on retrofits and some basement details because it gives the assembly a drying path in both directions.

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.

Does it matter where the sheet meets the ceiling and floor?

It is the whole job. Left loose at the top or bottom plate, warm air simply goes over or under a perfectly installed sheet. The junction into a vaulted ceiling is the most commonly skipped and the wettest point in the room.

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.