{"id":92703,"date":"2019-08-06T10:05:30","date_gmt":"2019-08-06T14:05:30","guid":{"rendered":"https:\/\/www.constructionspecifier.com\/?p=92703"},"modified":"2019-08-02T09:06:36","modified_gmt":"2019-08-02T13:06:36","slug":"back-to-basics-differences-between-air-and-vapor-barriers","status":"publish","type":"post","link":"https:\/\/www.constructionspecifier.com\/back-to-basics-differences-between-air-and-vapor-barriers\/","title":{"rendered":"Back to basics: Differences between air and vapor barriers"},"content":{"rendered":"

by Peter Barrett<\/strong><\/p>\n

\"Image<\/a>
Image courtesy Audain Art Museum<\/span><\/em><\/figcaption><\/figure>\n

It has been said before, but bears repeating: as much as 80 percent of premature building wear expenses are related to moisture<\/a> in one way or another. Water is the most significant factor in the premature deterioration of buildings, as it can cause corrosion of metals, rotting and mold in organic substances, dissolution of materials, reduction in effectiveness of insulation,
\nand more.<\/p>\n

Building industry professionals largely agree on the importance of moisture control methods, but there is frequent confusion about the use of vapor and air barriers<\/a>. To make the right decision on which methods and materials to include in a building envelope, it is critical to understand the simple, yet significant, differences between air and vapor barriers, and their role as part of an effective system.<\/p>\n

Air barrier function<\/strong><\/p>\n

\"Figure<\/a>
Figure 1:<\/strong> Ratio of continuous insulation (ci) to cavity insulation.<\/span>
Images \u00a9 Joe Lstiburek<\/span><\/em><\/figcaption><\/figure>\n

An air barrier\u2019s function is primarily to stop air leakage and resist differences in air pressure by keeping the indoor climate regulated. Simply put, air barriers keep the outdoor air out and the indoor air in. An air barrier should be:<\/p>\n