The membrane that makes the whole envelope work.
The air and vapour barrier is the layer nobody sees and everybody depends on. Get it wrong and the building leaks air, wastes energy and grows condensation inside the wall. Get it right and everything installed on top of it — insulation, cladding, roofing — performs the way it was designed to.
We install continuous membrane systems to the drawings, detailing every window opening, transition and penetration so there is no weak point for air or moisture to exploit.
What this covers.
Self-adhered membrane systems
Continuous sheet membrane air/vapour barriers installed across the wall assembly.
Fluid-applied air barriers
Spray or roller-applied air barrier coatings for substrates where a membrane isn't the right fit.
Window & door opening detailing
The rough opening is where most air barriers fail. We tape, flash and lap it correctly, every time.
Wall-to-roof transitions
Continuity carried across the transition between wall and roof assemblies, not stopped at the parapet.
Penetration & joint sealing
Every pipe, conduit and control joint sealed back into the barrier system, not left as a gap.
Commissioning-ready installs
Installed to a standard that holds up under third-party air-leakage testing and commissioning review.
Why it matters.
Air leakage through a poor barrier drives up heating and cooling costs for the life of the building.
A continuous vapour barrier keeps moisture from condensing inside the wall assembly where nobody can see it.
Installed to meet the air-leakage and energy performance requirements in the current building code.
Insulation, cladding and roofing all tie back into this layer — get it right first.
Hydro One. School boards. Builders. Property management.
Capital Exterior is run by a tradesman, not a sales team. Our founder started Cover-Tite's metal division, then spent years at Flynn Canada before going out on his own — 15+ years in the building envelope trade.
Straight answers, no runaround.
What is the difference between an air barrier and a vapour barrier?
An air barrier stops air from moving through the wall assembly; a vapour barrier controls moisture diffusion. Many modern assemblies combine both functions in one membrane, installed continuously across the building.
Why does continuous coverage matter?
A single gap at a window opening, transition or penetration can undo the performance of the whole system. We detail every joint, corner and transition so the barrier is actually continuous, not just installed on the flat wall.
Do you install from architectural drawings?
Yes. We install to the documented assembly and manufacturer spec, not to guesswork, so the envelope performs and the warranty holds.
Does this affect my building's energy performance?
Yes. A continuous, well-detailed air and vapour barrier reduces air leakage and condensation risk, which directly affects heating and cooling costs and helps meet code-required energy performance.
What areas do you serve?
Ottawa and the region: Gatineau, Kanata, Orleans, Nepean, Stittsville and out toward Kemptville. If your site is in the NCR, ask us.
Tell us about the project.
Send the scope and any drawings and we will come back with a straight quote and a realistic schedule. Prefer to talk it through? Call and we will walk through it.