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Crawl Space Vapor Barrier
One of the main reasons mold grows in a crawl space is because of the moisture emitted from the ground under the home. A crawl space vapor barrier reduces the moisture that rises into the crawl space.
The N.C. Building code requires that any “vented” crawl space has at least a 6-mil plastic covering the ground, and it must overlap at the seams at least 12 inches.
Homeowners in Charlotte, Winston Salem, and Hickory areas can trust Dry Otter Waterproofing for premium vapor barrier installation. So if you need a crawl space barrier… “You Otter Get Dry!”
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What is a crawl space vapor barrier?
A crawl space vapor barrier is a sheet of plastic installed over the soil in a crawl space. Its used is to block moisture vapor from rising out of the ground and entering the crawl space air. This helps prevent mold, wood rot, and humidity damage. Vapor barriers are sometimes referred to by brand names like Visqueen, or described as crawl space liners or underlayment.
How thick is a vapor barrier installed by Dry Otter?
Dry Otter installs black plastic that is 10mil thick. Plastic sheeting is measured in mils.
A mil is a measurement that equals one-thousandth of an inch, or 0.001 inch.
One mil also equals 0.0254 mm (millimeter). A mil is not the same thickness as a millimeter. “mil” is not an abbreviation but a unit of measure.
What are the steps to install a vapor barrier?
Installing a crawl space vapor barrier involves the following steps:
- Clean the crawl space and prepare the materials.
- Roll out the vapor barrier.
- Stake down the vapor barrier to the edges of the crawl space.
What are the benefits of a vapor barrier?
A plain vapor barrier on the crawl space floor alone is less beneficial than a complete encapsulation. Still, a crawl space vapor barrier can reduce the moisture from the soil into the wooden parts of the foundation.
According to the U.S. Environmental Protection Agency (EPA), up to 50% of the air on your first floor comes from your crawl space. That means any moisture, mold, or contaminants below your home can affect the air you breathe every day, making vapor barrier protection not just one of structural importance, but of health importance too.
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What are the signs you need a vapor barrier
- Musty odors
- Visible condensation on crawl space surfaces
- Warped hardwood floors
- Mold or mildew on joists or insulation
- High indoor humidity levels
- Increased allergy or respiratory issues
- Pest infestations
- Cold floors
- Wet Insulation
What are the dangers of a humid crawl space
- Mold and mildew growth
- Wood rot and structural damage
- Increased energy costs
- Poor indoor air quality
- Pest Infestations
How much does does vapor barrier installation cost?
The cost to install a crawl space vapor barrier typically ranges from $1,200 to $4,000, depending on several factors:
- Size (square footage) of the crawl space
- Height of a the crawl space
- Type and thickness of the vapor barrier
- Condition of the crawl space
Frequently Asked Questions
How much does it cost to install a vapor barrier in a crawl space?
The cost to install a crawl space vapor barrier typically ranges from $1,200 to $4,000, depending on several factors:
Size (square footage) of the crawl space
Height of a the crawl space
Type and thickness of the vapor barrier
Condition of the crawl space
How long does it take to install a crawl space vapor barrier?
Most waterproofing jobs can be completed in just a few days. During your inspection, we’ll walk you through the process so you’ll know exactly what to expect. We believe in clear communication and on-time service, so we’ll keep you informed every step of the way. No surprises, just solid results.
How long does a vapor barrier last?
Vapor barriers typically last 20 years or more, depending on the material and installation conditions. If water intrusion is not addressed though before the vapor barrier installation, the water can push the vapor barrier out of place.
Crawl Space Vapor Barrier Case Study
- Vickie
- Crawl Space Waterproofing
- Crawl Space Vapor Barrier
- Lincolnton, NC
Vickie called Dry Otter when her termite company let her know they found moisture and mold issues in the crawl space.
We inspected the crawl space and also identified mold and high moisture levels. He offered two ways to address the mold. One way is to clean the mold and replace the insulation. Then, install a full encapsulation of the crawlspace to seal the vents. Additionally, we would add plastic vapor barrier, also known as a liner, on the floor and the walls, with a dehumidifier to remove the moisture.
This solution would ensure the crawlspace was a poor environment for mold to grow back. Vickie chose to remove the insulation, clean the mold in the crawlspace, add a vapor barrier on the ground only to keep the moisture from coming up from the soil under the home, and replace the insulation.
Noah’s crew completed the job to provide Vickie with a mold free crawlspace, and a traditional vapor barrier for a vented crawl space.
More Case Studies
What Our Customers Are Saying
EXCELLENT Based on 414 reviews Posted on Reg KingTrustindex verifies that the original source of the review is Google. We needed to have our crawl space "updated" in order to feel good about handing over the home to a new owner after 38 years! The service prior to the sale was thorough, informative and substantiated the costs of each part of the process. When the crew arrived on-site they were prompt, held a consistent clean work area, did a very neat "top drawer" job! Most of all they respected all of our property which is very important when bringing in outside agents! We appreciate the ownership and the young men who completed the work.Posted on David DouglasTrustindex verifies that the original source of the review is Google. Trey Moore, a Dry Otter tech came to our house on 6/3/26 for an annual review. He was punctual, courteous, and thorough.Posted on Joyce KluttzTrustindex verifies that the original source of the review is Google. We had an excellent experience with everyone who worked under our house. The initial inspection done by Mike revealed many things we didn't know, and the report was presented in a way I could understand. The drainage system was done first and fast, followed by a goodly amount of joist and sill repair, professionally done. The encapsulation was done by William and Josh, who did great work and made several trips to our house to make sure we were satisfied. It looks good under there. The new electric lights and switches will make future drain cleaning and pest inspections much easier than before.Posted on Donald NewmanTrustindex verifies that the original source of the review is Google. Outstanding performance. Arrived on time and worked all day. Completed encapsulation on time. Price was competitive. John, Corey, Desmond, Adam, Trey and Patrick were very professional and maintained communications with me. Always knew the status of the project. Great crew all around. Highly recommend Dry Otter for the Denver Area encapsulation. Crawlspace is great.Posted on ScottTrustindex verifies that the original source of the review is Google. Dry Otter has provided me with excellent, professional service since reaching out to them to upgrade my crawl space. Their competent service and technical expertise was always helpful. Also, their response to any questions or help was always met in a very timely manner. I want to call out specifically Adam, Trey, and Heather for all the assistance they provided. They went "above and beyond". I would recommend Dry Otter (and have numerous times) to anyone needing help with waterproofing services. Again, thank you Adam, Trey, and Heather...Posted on Damien KalacTrustindex verifies that the original source of the review is Google. Both Will & Josh were great installing vapor barrier for my crawl space. Efficient, knowledgeable and friendly. Highly recommend.Posted on CJTrustindex verifies that the original source of the review is Google. Excellent experience with this company, from Mike providing a thorough free crawlspace inspection, explaining the options and services for my crawlspace issues. To the completed encapsulation project with dehumidifier….Will and Josh did an amazing job, explaining the process and open to my questions along the way! I would highly recommend this company! Thank you!Posted on KathrynTrustindex verifies that the original source of the review is Google. Contacted dry otter for installing a dehumidifier and encapsulation, they promptly scheduled an estimate and were willing to work with me about what I could accommodate in terms of budget. The service was scheduled quickly (about 2 weeks). The crew, Will and Josh (under the Denver NC location), were very communicative and let me know of their arrival time and updates through the day. They were very professional, timely, and friendly. The work completed was very professional and well done. I would 10/10 recommend them to anyone looking for crawl space services!Posted on Fran EarlTrustindex verifies that the original source of the review is Google. troy was every good , he change the battery in the monitor and answer all my




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Our process includes the following inspections:
Crawl Space Inspection:
- Moisture and Water Damage
- Mold and Fungus
- Insulation Condition
- Vapor Barrier
- Structural Issues
- High Humidity
- Condensation on Ducts
Basement Inspection:
- Water Intrusion
- Cracks and Wall Leaks
- Foundation Integrity
- Sump Pump Operation
- Mold and Mildew
- Basement Floor Cracks
- Hydrostatic Pressure
Our expert will personally visit your home and examine the issues you are having with your basement or crawl space foundation.
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