Insulation Services
Air Sealing & Vapour Barrier Installation
Overview
About Air Sealing & Vapour Barriers
Insulation slows heat flow, but it does little to stop air. Warm, moist indoor air that leaks into a wall or attic carries heat with it and can condense on cold surfaces inside the assembly. That is why air sealing and vapour control are installed together with insulation, not as an afterthought.
KHG Insulation Services installs polyethylene vapour barriers, seals laps and edges with acoustical sealant and tape, and details penetrations at electrical boxes, pipes, and wiring. We also air seal attic floors and top plates before blowing insulation. As insulation contractors in the GTA, we see the same leakage points repeatedly and know where to focus.
In Ontario’s climate, vapour control is usually placed on the warm side of the insulation. The correct location and material still depend on the assembly and the design, and on permitted work we follow the drawings and the applicable code requirements. If the drawings and site conditions do not agree, we raise it with the builder or designer before the barrier goes up.
Reference imageScope of Work
What the Service Involves
- Vapour barrier installation
- Installing polyethylene sheet over insulated walls and ceilings, lapped over framing members and sealed at the edges.
- Sealing laps and joints
- Sealing overlaps and perimeter edges with acoustical sealant and sheathing tape so the barrier is continuous.
- Electrical box detailing
- Sealing at outlets and switches with vapour-barrier boxes, gaskets, or sealant where the design calls for them.
- Penetration sealing
- Sealing around pipes, wiring, ducts, and other penetrations through top plates, ceilings, and the barrier itself.
- Attic air sealing
- Sealing accessible top plates, ceiling penetrations, and gaps at the attic floor before new insulation is added.
Applications
Typical Project Applications
- Exterior walls before drywall
- Ceilings below attics
- Basement wall insulation
- Attic floors before topping up
- Additions and renovations
- New construction framing
Materials
Insulation Materials Used
Polyethylene vapour barrier
Sheet vapour barrier installed on the warm side of the insulation where the assembly calls for it.
Acoustical sealant and tape
Non-hardening sealant and sheathing tape used to seal laps, edges, and penetrations.
Boxes and gaskets
Vapour-barrier electrical boxes and gaskets that keep the barrier continuous at outlets and switches.
Benefits
Why Air Sealing & Vapour Barriers Matters
Less air leakage
Sealing penetrations and gaps reduces drafts and the heat carried out by leaking air.
Better insulation performance
Insulation works as intended when air is not moving through or around it.
Moisture kept out of the assembly
Correctly placed vapour control reduces the risk of condensation inside walls and ceilings.
Ready for inspection and drywall
A continuous, sealed barrier is easier to inspect and gives the drywall crew a clean surface.
What to Expect
From First Call to Installation
- 01
Describe the assembly
Tell us which walls or ceilings are involved, whether they are open, and whether you have drawings or a permit.
- 02
Assembly review
We review the wall or ceiling build-up and confirm where the vapour control and air sealing belong for that assembly.
- 03
Written quote
You receive a quote listing the areas, materials, and sealing details included.
- 04
Installation and check
We install the barrier and sealing, check laps and penetrations for continuity, and leave the area ready for drywall.
FAQ
Air Sealing & Vapour Barriers Questions
Related Services
Often Combined With
Attic Insulation
Blown-in attic insulation and top-ups in fiberglass or cellulose, with baffles at the eaves and attention to air leakage at the ceiling.
Learn more
Wall Insulation
Thermal and acoustic insulation for open wall framing in renovations, additions and new construction.
Learn more
New Construction Insulation
Coordinated insulation installation for residential new builds, additions, and construction projects.
Learn more
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