Air barriers / Guides

The difference between air barriers and vapour barriers
Air and vapour barriers

The Difference between air barriers and vapor barriers

...air barriers and vapor barriers The job of a vapor barrier is to prevent vapor diffusion, and the job of an air barrier is to stop air leakage through differences in air pressure. A wall system should have one vapor barrier, but can have many air barriers. A vapor barrier can act as a very effective air barrier, but ...

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

What is an air barrier?

...air leakage than is carried by vapor diffusion. That makes air barriers 100 times more important than vapour barriers, so why is no one talking about them? We don't talk about air barriers because we are too busy talking about vapor barriers. An air barrier is not something you walk into a building supply store and b...

Exterior air barrier membrane © Ecohome
Air and vapour barriers

How to install an air barrier for reduced air leakage

...air barriers and vapour barriers: The job of a vapour barrier is to prevent vapour diffusion and the job of an air barrier is to stop air leakage through differences in air pressure between inside and out. A wall system should have one vapour barrier, but can have many air barriers. A vapour barrier can act as a very...

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

Replacing polyethylene vapour barriers with latex paint vapor control

...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 carefully sealed, but so can other materials. Well-sealed drywall in itse...

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

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

...barriers and rainscreens play in a wall, choosing the right products and installation tips for optimum performance. They're officially known as water-resistive barriers or WRBs, sometimes weather-resistive barriers, but in practical terms they are more commonly called housewraps and weather barriers. With so many opt...

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

Interior sheathing as an air and vapour or vapor barrier

...air barrier, perhaps not realizing the importance of properly sealing those breaches afterwards. Because of that unfortunate reality and a general lack of prioritizing air barriers in the industry, under normal air pressure conditions the average brand new home can expect to have its entire volume of air leaked out and...

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

...Air-Con = Damp Moldy Walls So here's a little known fact that most HVAC installers won't tell a potential new client for central air; Polyethylene vapor barriers in combination with air conditioning in homes can rot walls because of the condensation they may cause. This is why if you have a newer home with a vapor ba...

Problem areas of air leakage in a home and blower door test being cond
Air and vapour barriers

Airtight Construction of Homes is Essential: "Your house sucks." "Oh yeah? your house blows!"

...Air Tightness in Houses - All about Balancing Air Pressure in the Home We go on incessantly here about the importance of air barriers in home construction to reduce air leakage , but no matter how hard you worked to make a house airtight, if the pressure isn't balanced you will be sucking air in or forcing it out and...

Blower Door Tests - What's the Cost & Who Does Them?
Air and vapour barriers

What is a blower door test? What's the cost? How do you find a company to do one?

...air leakage but, more importantly, it’s a way to find air leaks and fix them. Fixing air leaks is ‘low hanging fruit’ in terms of improving the energy efficiency of homes under construction since you already have to buy and install air barriers in the form of 6 mil poly vapor barriers , exterior weather resistant barri...

Condensation on windows leads to mold & mildew in homes, ERV & HRV systems help

Ventilation & air exchangers

...Air Conditioning) or HRVs (Heat Recovery Ventilators). The point of these systems is to remove moisture and provide fresh air to your home that is pre-heated by the outgoing air. © Van EE The core of an HRV has small separated channels that air passes through, allowing incoming air to be preheated by exhaust ai...

How to Vent Roofs - the Methods, Vent Types, Fans
Walls and Roofs

Why Roofs need to be ventilated and how to ventilate a roof properly

...air and vapor barriers. Warm air rises, so there is always more air pressure at the higher points of any house or building, as in the top floor ceiling. And air will find any hole no matter how small it is. Wind pressure as well as interior mechanical ventilation also affects the air pressure in a home and will force...