Reader Question: Are Vapor Barriers Safe?

This was an interesting question that someone asked me the other day. Every application that I’ve ever used Vapor Barriers in have been safe but I was still startled that I didn’t have a more detailed answer as to “Why they are safe.” I decided to look into it further.
Vapor barriers are inherently safe. There are however, ways of using them and installing them improperly that make them unsafe. The good news is that there are things to look into and look out for when researching a vapor barrier for your basement or construction project.

Vapor Barriers are typically a thin sheet of plastic (composition varies from brand to brand), normally polyethylene, that are placed on basement walls, or on new home walls to minimize the amount of moisture, water, and or air from penetrating into the home.

Being that vapor barriers and diffusers are now considered normal parts of most construction projects (residential and commercial) there are things that have to be considered. Introducing a vapor barrier on the 1st and 2nd floor requires a different list of considerations than those installed on the foundation itself. With the two areas being drastically different in how moisture and liquid water attempt to enter the spaces, the grade of vapor barrier and the way that it’s installed has to be different.

To make sure that you’re using the right Vapor Barrier for your basement moisture control and installing it the right way follow these simple tips:

1.) Find a Vapor Barrier (Not a diffuser) with a PERM rating of .001 or lower. The lower the number the better it can stop moisture from coming through.

2.) Don’t install it on the front of your studs before placing dry wall on top of it. This is the wrong way to do things. Vapor barriers should always be installed directly on the foundation wall.

3.) Make sure the vapor barrier is smooth and that all openings are sealed, taped or caulked closed. This will limit air transfer and will help to make sure that your vapor barrier isn’t allowing any bad things to come with the air from underneath your basement floor.

4.) Run your vapor barrier to an interior drain system like the GrateDrain. If you don’t you’ll end up with pools of water, moisture and condensation along your bottom edge. Connecting your vapor barrier to a drain controls where the moisture/water end up. Channeling it to a drain system fully protects your wall.


And here are a few “common sense” safety tips:

*Keep out of the mouths of children
*Don’t let a child or a person wrap a vapor barrier around their nose or mouth
*Don’t stab pointy, sharp or jagged objects into the vapor barrier, you can puncture it and render it useless.
*Use a Basement Health Contractor to properly install this vapor barrier.
*Don’t install it on the outside of finished studs in the basement.