Why Crawl Space Ninja Uses 12 Mil Vapor Barriers: Ensuring Long-Term Protection and Air Quality

Why Crawl Space Ninja Uses 12 Mil Vapor Barriers: Ensuring Long-Term Protection and Air Quality

Posted by Arthur Jackson on May 28th 2024

Crawl spaces and basements are critical areas in any home. They are often prone to moisture problems that can lead to mold growth, structural damage, and poor indoor air quality. One effective solution to these issues is the installation of a vapor barrier. At Crawl Space Ninja, we prefer using a 12 mil vapor barrier, and here's why:

The Downside of Chemical Adhesives in Vapor Barriers

Many vapor barriers on the market today use a chemical adhesive to bond the layers of plastic together. While this might seem like a minor detail, it can have significant long-term consequences:

  1. Peeling and Degradation: Over time, the chemical adhesives used in these barriers can begin to break down. This degradation can cause the layers to peel apart, compromising the barrier’s integrity and effectiveness. When the adhesive fails, the vapor barrier can no longer effectively prevent moisture from entering the crawl space or basement.
  2. Odor Issues: As these adhesives degrade, they can emit unpleasant odors. One particularly concerning smell is often compared to cat urine, which can permeate the entire home. This odor, sometimes referred to as “pneumonia smell and musty smell" can be both irritating and difficult to eliminate.
  3. The 12 Mil Vapor Barrier we use to service homes and that is on sale on our DIY Store is a Polyethylene woven plastic with no adhesives or chemicals made within the plastic.  

The Benefits of a 12 Mil Vapor Barrier

At Crawl Space Ninja, we have chosen to use a 12 mil vapor barrier for several important reasons:

  1. Durability and Flexibility: A 12 mil vapor barrier strikes the perfect balance between durability and flexibility. Thinner barriers, like 6 or 8 mil, may not provide sufficient protection against punctures and tears. However, a 12 mil barrier is robust enough to withstand normal wear and tear while remaining flexible enough to be installed around obstacles and tight spaces commonly found in crawl spaces and basements.
  2. Chemical-Free Adhesion: Our 12 mil vapor barriers are constructed without the use of chemical adhesives. This means there is no risk of peeling or degradation over time, ensuring long-lasting performance and maintaining a strong seal against moisture. Homeowners can have peace of mind knowing that their vapor barrier will remain intact and effective for years to come.
  3. Optimal Protection: The thickness of a 12 mil vapor barrier provides optimal protection against moisture and ground gases like radon. It is thick enough to create a reliable moisture barrier while still being manageable during installation. This ensures that your crawl space or basement stays dry and contributes to a healthier indoor environment.

The Drawbacks of Thicker Vapor Barriers

While it might seem like a thicker vapor barrier would offer even better protection, this isn’t necessarily the case for crawl spaces and basements:

  1. Rigidity and Installation Challenges: Thicker barriers, such as 20 mil, tend to be much more rigid and difficult to work with. This rigidity can make it challenging to install the barrier properly around the various obstacles and tight corners typically found in these spaces. Poor installation can lead to gaps and breaches in the barrier, reducing its effectiveness.
  2. Cost and Practicality: Thicker vapor barriers are also more expensive and may be overkill for the majority of residential applications. A 12 mil barrier provides a cost-effective solution that offers superior protection without the unnecessary expense and hassle associated with thicker options.


Choosing the right vapor barrier for your crawl space or basement is crucial for maintaining a healthy and structurally sound home. At Crawl Space Ninja, we use a 12 mil vapor barrier because it offers the perfect combination of durability, flexibility, and long-term reliability. By avoiding chemical adhesives and opting for a barrier that is both effective and easy to install, we ensure that your home remains protected from moisture and the associated risks.

If you’re considering a vapor barrier for your home, trust in a solution that prioritizes quality and longevity. A 12 mil vapor barrier from Crawl Space Ninja is an investment in the health and safety of your home and loved ones.