If you are wondering if you can get away with not having an underslab vapor barrier plastic underneath the concrete of your building project? The short answer is no; for many reasons, ASTM compliance standards require vapor barrier plastic underneath concrete slabs.
Vapor barriers protect not only the building project itself but the people inside. Underslab vapor barrier plastic protects a building’s foundation from environmental damage caused by moisture, pests, and extreme temperatures.
Call our vapor barrier experts today at 760-388-6294.
Why Do Builders Need an Underslab Vapor Barrier Plastic?
An underslab vapor barrier protects the subfloor and, subsequently, the main floor from moisture by adding a protective layer underneath the concrete foundation before it is poured on wet.
There’s water in the ground underneath every building. The water is not always near the surface and therefore is invisible to a plain observer. Even if the concrete foundation is enough to keep water away from the building, water vapor can easily rise to the surface and damage a building’s foundation, subfloor, and main floor. A vapor barrier is crucial to protect a building from the many negative effects of water vapor on building materials.
“Without a vapor barrier, concrete will deteriorate much faster through water vapor intrusion which degrades the quality of the concrete over time and can lead to foundation and building failures, like Surfside Condominium Collapse in Miami, Florida,” says vapor barrier plastic sheeting expert and Americover account manager Charlie Adkins. “For minor projects, the absence of a vapor barrier leads to water intrusion, leading to an unstable foundation or a cracked slab.”
The American Society for Testing and Materials (ASTM) outlines national standards for underslab vapor barriers. ASTM E1745, the Standard Specification for Plastic Water Vapor Retarders Used in Contact with Soil or Granular Fill under Concrete Slabs, specifies that vapor barriers for underneath concrete slabs should be Class A vapor barriers.
Related Article: Your Installation Guide to Underslab Vapor and Gas Barriers
What Happens if You Don’t Use an Underslab Vapor Barrier?
Without a under slab vapor barrier there will be damage to the flooring, poor climate control, and increased danger from of radon gas. A vapor barrier prevents these common adverse effects:
Damage to the Flooring
Water vapor can penetrate through the concrete subfloor and damage the main floor of builds, causing deterioration of flooring adhesive; bumps, ridges, or bubbles under flooring, color changes due to fading, mold, mildew, bacteria growth; peaking, curling, or warping of flooring; or efflorescence, also known as the build-up of mineral salts.
Climate and Energy
Concrete holds temperature better than less conductive materials like wood. Vapor barriers can often double as added insulation, protecting buildings against excess cold and heat. Failure to use a vapor barrier can lead to higher energy costs and an ideal environment for mold and mildew growth.
Radon Gas Intoxication
Radon gas, which comes from underneath the floor of buildings, is the second leading cause of lung cancer behind smoking. Installing a radon vapor barrier with a radon mitigation system prevents radon from accumulating inside the building and helps protect the foundation.
The Best Underslab Vapor Barrier Plastic for Concrete Slabs
Americover is your one-stop shop for vapor barriers that pass ASTM E1745 Class A, B, and C standards. To find the right material for your project, contact the experts at Americover. You can lean upon our decades of experience and exceptional customer service to overcome your project’s challenges. For example, for smaller residential projects, we may recommend a product like Pro Crawl Barrier vs. using something like our 20 Mil Dura Skrim® Reinforced Plastic Sheeting.
Take a look at the various perm rating classifications below:
ASTM E1745 Perm Rating Classifications For Underslab Vapor Barriers
| Product/Classification Based on ASTM E1745-11 Requirements | Water Vapor Permeance | Tensile Strength | Puncture Resistance |
|---|---|---|---|
| Class A Requirement | 0.10 perms | 45.0 lb/in | 2200 grams |
| Class B Requirement | 0.10 perms | 30.0 lb/in | 1700 grams |
| Class C Requirement | 0.10 perms | 13.6 lb/in | 475 grams |
| Vapor Barrier Product | |||
| Vapor Barrier yellow 10 mil | 0.0228 perms | 61.0 lb/in | 3210 grams |
| Vapor Barrier yellow 15 mil | 0.0158 perms | 80.0 lb/in | 3930 grams |
| Vapor Barrier blue 10 mil | 0.018 perms | 58.0 lb/in | 3000 grams |
| Vapor Barrier blue 15 mil | 0.0078 perms | 64.0 lb/in | 4000 grams |
| Vapor Block 15 | 0.0057 perms | 78.0 lb/in | 3300 grams |
| Vapor Block 10 | 0.0146 perms | 52.0 lb/in | 2600 grams |
| Vapor Block 20 Plus | 0.0098 perms | 58 lbf | 2600 grams |
ASTM E1643 Installation Instructions
Once you’ve chosen the underslab vapor barrier that’s right for your project, it’s important to follow ASTM E1643 guidelines when installing it. Here’s a quick overview of what’s involved:
- Overlap vapor barrier seams by six inches.
- Seal seams using manufacturer recommended products.
- Seal around permanent penetration.
- Avoid causing any punctures or tears in the vapor barrier.
- Repair any visible damage to the vapor barrier.
- Seal the vapor barrier at edges where it meets the concrete slab.
Trusted by Growers, Builders, and Distributors
Americover is the smart source for plastic and polyethylene 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 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.