"Learn how to correctly seal your crawlspace and eliminate hazardous dust, mold, and mildew."

How to Install Vapor Barriers In A Crawl Space

Mold in air conditioning ducts is common is many homes.  Mold results in musty smells, allergies, and sometimes-serious health problems.  Proper HVAC duct construction and a crawl space vapor barrier installation helps eliminate mold growth.

When sealing a crawl space, I suggest using a 10 to 20 mil plastic or polyethylene vapor barrier.  A 16 mil plastic vapor barrier should be heavy enough to resist punctures during installation.  A tip when installing vapor barriers in a crawlspace is to overlap each section one foot or so, then use a short piece of duct tape about every three feet along the seam to hold it together and prevent gaps.  Turn the vapor barrier up the wall about eight inches and make sure there is contact between the barrier and the wall.  It is not necessary to seal it with anything; however, it will not hurt if you do seal it to the wall using a double sided tape or caulk.  You need to close the vents on the outside walls, too.  If you leave them open, humid air from the outside enters the crawlspace.

Excess condensationleads to mold and mildew problems. When warmer humid air comes in contact with the colder surface of your ductwork, it causes condensation.   Musty odors in your home are sometimes referred to as "dirty sock syndrome". Any leakage in your ductwork causes moisture and odor to be brought into your house.

If you are searching for a solution for a basement vapor barrier, please call me at my office at 501-653-7931.  Vapor barriers cannot be covered with a "blanket" answer.  Several factors must be taken into consideration when considering a basement vapor barrier.

 doug rye
Doug Rye
 New Home Design
Ultimate Energy
Action Guide