The foundation of a building has a great deal to do with the overall structural health of the building. As a builder wanting to produce the best work for your project, you deserve materials to help you meet compliance requirements and complete your project to the highest standard of quality. An underslab vapor barrier ensures that your building project remains structurally sound from the ground up.
If you are seeking a specified underslab vapor barrier product for your construction project, the team at Americover can serve you as leading professionals in construction plastic sheeting. We can help you find the exact product that meets the specifications for your building project.
Read below to learn more about underslab vapor barriers and mil thickness requirements.
Why Install an Underslab Vapor Barrier?
The purpose of an underslab vapor barrier is to protect your building structure from damage that can begin from underneath your concrete foundation. Common issues that an underslab vapor barrier prevents include:
- Ground moisture migration that can rise through porous, concrete material
- Harmful or lethal gas migration, especially radon gas and methane present in the ground
- Energy inefficiency that occurs when untreated air enters the structure through the foundation
- Noncompliance of national building codes and safety regulations
Related Article: Why Should I Install an Underslab Vapor Barrier?
What Mil Thickness Should an Underlab Vapor Barrier Be?
While a 6 mil vapor barrier is a popular choice for many construction applications, the team at Americover, recommends that an underslab vapor barrier be at least 10-15 mils. This is due to the 2021 edition of the International Residential Code (IRC), which revised its guidelines to recommend a minimum 10 mil vapor barrier in order to meet the requirements of a Class A vapor barrier.
For clarification, note that a mil (mil) is not a millimeter (mm). Mils are unique units of measurement used for sheeting. A mil is equivalent to 0.0254 millimeters, or 0.001 inches.
Vapor barriers for underneath concrete slabs should be Class A barriers, meaning that they have a water vapor permeance of 0.1 perms or less and a tensile strength of 45 lbs. per square inch, and a puncture resistance of 2200 grams. Since mil thickness is correlated with permeance, your vapor barrier must be thick enough to meet compliance requirements.
If you don’t know whether your vapor barrier plastic is a Class A barrier, check the manufacturer label, talk to your plastic sheeting professional at Americover, or visit our underslab vapor barrier resource page.
Other Factors for Consideration
When choosing the best vapor barrier for your underslab application, there are additional factors you may consider to choose the best material for your needs, including:
- Budget: A larger budget can accommodate a more premium product, whereas a smaller budget only allows for the most economical solution. At Americover, even our most cost-effective vapor barriers meet the minimum requirements for underslab vapor barriers.
- Puncture Resistance: A higher puncture resistance means that your plastic sheeting can withstand heavier-duty projects. A 6 mil vapor barrier may not be able to withstand all the rigorous activity that takes place on a construction site while building a foundation.
- Radon Blocking: Most underslab vapor barriers should have some gas blocking technology, but for construction areas that present an especially high risk, a specialized product that adds that specific layer of protection can be beneficial to your project.
Top Recommended Underslab Vapor Barriers:
VaporBlock® Plus™ 20 Mil Vapor Retarder/Gas Barrier is one of the most effective under-slab gas barriers in the building industry today far exceeding ASTM E-1745 Class A, B, and C requirements
VAPORBLOCK® is a high performance underslab vapor barrier designed to retard moisture migration through concrete slabs-on-grade. VAPORBLOCK® vapor barriers exceed ASTM E-1745 Class A, B, and C requirements.
Vapor Barrier Yellow is composed of polyolefin resins to create a puncture resistant vapor barrier for use under concrete slabs to stop moisture migration and reduce mold, mildew, and fungus.
Vapor Barrier Retarders are composed of high-performance polyolefin resins to create a highly puncture-resistant vapor barrier for use under concrete slabs or in the building envelope.
Pro Crawl Barrier is a 10 mil Class 1 Vapor Barrier with a high gloss white finish offering low permeability and excellent tensile strength. Great for us in smaller underslab vapor barrier projects.
Trusted by Builders, Growers, and Distributors
Americover is the smart source for polyethylene plastic sheeting. Trusted by contractors and distributors across the construction and agriculture industries, our American-made products combine reliability with quality and innovation.
As an Americover customer, you will receive the personalized support of a dedicated account manager to simplify the ordering process and ensure the best solution for every one of your projects. Our friendly, knowledgeable staff is here to answer your questions and fulfill orders Monday-Friday from 7:30 a.m. to 4:30 p.m. Pacific Standard Time. If you would like to speak with a representative, call us at 760-388-6294 or contact us.