Vapor Barrier Sheathing: What Is It?
The term “vapor barrier” refers to a thin film of non-conductive material applied over the interior surface of a building or structure to prevent conductivity from passing through it. A vapor barrier can be made up of one or more layers. These are usually plastic sheeting, foam rubber, wood veneer, metal mesh, glass fiber fabric and even polyurethane (PU).
A vapor barrier is not just a physical barrier; it’s also a design feature that helps reduce energy consumption and noise. According to the U.S.
Green Building Council, installing a vapor barrier reduces heating and cooling costs by 20% compared to conventional construction methods.
Why Would I Need To Install One?
In most cases, when you have air leaks in your home, they’re caused by either faulty wiring or inadequate insulation. When these problems occur, heat and cold flow into the house but don’t get out. Air conditioning units use this trapped heat to work properly, so if there is no way for air to escape, then the temperature inside will continue to rise. If you’ve ever had a hot summer day without air conditioning, you’ll understand what I’m talking about.
There are other times when air can find its way into your home through more complex means. If air pressure outside is higher than the air pressure inside, then it will slowly seep in over time. This can cause a drop in oxygen levels in your home.
If it’s cold outside, then that cold air can also seep in and cause your heating unit to work overtime.
If you live in a windy area, then this problem is even worse. Strong winds can actually bend and warp your house if it’s made out of wood or other natural materials. It can also cause your roof to lift up at one end.
Installing a vapor barrier is the best way to prevent these problems from occurring in the first place.
What Should I Know About Vapor Barrier Installation?
When you’re installing a vapor barrier, there are certain things that you should know beforehand. First of all, you need an interior and exterior vapor barrier. The interior barrier should be installed before drywall. The exterior barrier typically goes on after the siding or stucco has been properly installed. Most types of insulation can be installed over vapor barriers so there is no need to remove them unless the instructions tell you otherwise.
In some climates, it’s actually recommended that you install two layers of exterior barrier so one layer doesn’t get damaged by lawn mowers or other yard maintenance equipment.
Should I Use Tyvek Or Plastic Sheeting?
Tyvek vs. plastic sheeting – which one is better? Both do an adequate job of preventing air leaks in your home. While plastic may be slightly stronger, it’s also thicker and more difficult to install. For most do-it-yourself projects, Tyvek is easier to work with so most homeowners choose that instead.
Sources & references used in this article:
Air and vapor barrier sheathing system by D Faucher – US Patent App. 10/338,857, 2004 – Google Patents
Insulated reinforced foam sheathing, reinforced vapor permeable air barrier foam panel and method of making and using same by RI Ciuperca – US Patent 8,966,845, 2015 – Google Patents
Understanding vapor barriers by JW Lstiburek, P Eng – ASHRAE journal, 2004 – buildingscience.com
Composite vapor barrier panel by G Moras – US Patent 6,279,284, 2001 – Google Patents
Insulated sheathing panels by R Crawford – US Patent App. 10/684,672, 2005 – Google Patents
Insulated reinforced foam sheathing, reinforced vapor permeable air barrier foam panel and method of making and using same by RI Ciuperca – US Patent 9,366,023, 2016 – Google Patents