Vapor barrier vs air barrier / Green Building & Sustainable Home Renovation Information & Advice

Walls and Roofs

Why Your Walls Get Wet: A 'Building Science Made Easy' Guide to Understanding the Dew Point

...Air barriers: stopping the conveyor belt of water An air leak is like a conveyor belt that fast-tracks warm, humid air into your walls. While a vapor barrier stops moisture from slowly soaking through a solid material, an air leak moves about 100 times more water. If that air hits its dew point while passing through yo...