Vapour Barrier Installation Elmwood Park Edmonton

Poly and air sealing in Elmwood Park 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.

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

Vapour Barrier Installation Elmwood Park Edmonton

Bathrooms, kitchens and the wet rooms

Elmwood Park drywall in context

Warm side, always

Never two barriers

What a vapour barrier is not

The rim joist and the bottom plate

Electrical boxes, the usual failure point

Simple, clean, on schedule — Vapour Barrier Installation in Elmwood Park Edmonton

Vapour Barrier Installation Elmwood Park Edmonton: your questions answered

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.

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.

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.

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.

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.

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.