Vapour Barrier Installation Sherbrooke Edmonton

Poly and air sealing in Sherbrooke before the board goes on

A vapour barrier only works as a continuous plane. In Sherbrooke 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
• Window and door returns detailed properly
• Left ready for inspection before boarding
• Rim joists air-sealed before insulating
• Electrical boxes poly-hatted and sealed
• Poly on the warm side of the insulation

Vapour Barrier Installation Sherbrooke Edmonton

Inspection, and leaving it visible

Sherbrooke drywall in context

Where poly is the wrong choice

Never two barriers

Basement walls, where the rules change

Bathrooms, kitchens and the wet rooms

The parts an inspector looks at first

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

Vapour Barrier Installation Sherbrooke 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.

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

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 Sherbrooke 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.

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.