What is an air barrier / Guides

Air barriers are essential to a properly functioning wall system
Air and vapour barriers

What is an air barrier?

...barrier, and it goes on the warm side of the insulation. Air barriers on the other hand, can be anywhere in the wall assembly and as plentiful as you like. It is highly unlikely that your air barrier will be flawless, so by all means have a second and a third. This is what is referred to as the 'belt and suspenders' ap...

Vapor retarder latex primer instead of polyethylene sheet
Air and vapour barriers

Replacing polyethylene vapour barriers with latex paint vapor control

...barrier is mistaken for, and almost entirely relied upon to act as the air barrier. The purpose of the two barriers should not be confused - the job of the vapour barrier is to control vapour diffusion, the job of the air barrier is to control air leakage. 6 mil poly can work effectively as an air barrier if it is ca...

Interior sheathing as air & vapor barriers in wood frame construction
Air and vapour barriers

Interior sheathing as an air and vapour or vapor barrier

...ance. By moving the sheathing to the inside, you are simply letting it live up to its full potential as an air barrier and vapour barrier, and eliminating the need to install a separate product to do that job. One of the benefits of OSB as an air barrier is that it is solid. A polyethylene or foil air barrier can be ...

Tyvek home wrap left exposed to wind and UV rays
Air and vapour barriers

Choosing the right house wrap / weather barrier, which is best?

...and and Air Stop are three examples of tapes with much better adhesion. Peel-and-stick membranes: An alternative to the commonly used non-adhesive housewraps are the 'peel-and-stick' membranes, and if you'd like a fancier word for them, go with this - self-adhering air and water-resistive barriers. Peel-and-sti...

Passive House wall system ; Larsen Trusses & dense-packed cellulose insulation
Wall assemblies - new construction

Larsen truss wall systems with double-stud construction & extra insulation for new homes & energy efficient home renovation

...and batt insulation in the cavities, covered with sheathing, then I-joists (TGIs) attached to the exterior of the sheathing to allow for seamless insulation with no thermal bridging . The sheathing is used as the air barrier and vapor barrier , by using a high-performance building tape to seal the joints and the Larsen...

Off grid, passively heated and cooled house in the Gatineau Hills, Que
Off-grid and Net-Zero Housing

Off grid living blog, part 2: passively heated, this house in Quebec aims for LEED certification

...and hydro pole, so truly off-grid, Craig Anderson and France-Pascale Ménard had no option but to go for extreme efficiency in design, product selection and construction. Craig and France-Pascale went for LEED certification through the CaGBC, and this is how they went about it. This is the second piece in a blog serie...

Air and vapour barriers

Aerobarrier home and attic air-sealing spray

...An air seal is thereby created around any openings and cracks in ceilings, walls, windows, plumbing and electrical penetrations. This is an easy way to plug holes in your air barrier that you can’t possibly see - from as small as a human hair to as big as a half-inch wide. The airflow in the home is monitored in real...

Poly vapour barriers in air conditioned houses can cause mold and rot
Healthy indoor air quality

Why you should Never Install Air-Con in a Home with a Vapor Barrier

...is the answer to not insulate? No, there isn't enough energy for that. Is the answer to not use composite wood materials? No, there aren't enough trees for that. What we need to do is acknowledge these changes, and design walls to handle moisture effectively. As most new North American homes are now e...

Choosing a building envelope
Wall assemblies - new construction

Choosing a building envelope - starting with the perfect wall

...what is the best wall system? That also depends on what you are looking for. What is the most durable wall? What is the most energy efficient wall? What is the most soundproof wall? What is the most affordable wall? That is just a short list of things to consider, and despite many people online saying they ha...

Celsius Solar Igloo
Solar thermal collectors

Celsius: The solar heated igloo!

...ante Us: What is Celsius insulated with? L. McC : The igloo is insulated from the noise and cold by 10,000 pounds of recovered clothing loaned to us for the event. The key to its performance is the continuity of the vapor barrier (interior) and the air barrier (exterior). Us: How is the sun used to heat and power the i...

Frost in Attics: What causes Attic Ice? How to Fix it?
Roof assemblies - renovation

Why is there frost in my attic? Is ice in roofs a problem & How do I stop it?

...an be blocked by snow, but snow isn't an air barrier. It will slow the air, but as long as the vent runs the length of the roof there should be enough air flowing through. you can apparently survive (for a time) after being buried in an avalanche if you don't panic and breath slowly. Since roofs aren't prone to panic a...