Crawl spaces are the hollow places under the floors of homes or buildings, especially for access to plumbing or wiring. They are a cheaper option than the expensive basements. However, locations with high humidity, coastal regions, or marshlands prefer to have crawl spaces to protect the building. Their height usually ranges from one to three feet. Because of their inconspicuous location, their problems are unique, and their maintenance requires special attention. Whether to go for Vapor Barrier Installation for crawl space humidity levels or for crawl space encapsulation for its maintenance can best be decided after understanding the nature of crawl space problems. 

Proper ventilation of crawl spaces is essential. It protects the structural integrity of the house and your health by regulating the moisture content in the house’s walls. If they are not appropriately ventilated, the moisture seeps through the cracks in floors and walls. This may deteriorate air quality, causing respiratory issues and allergies. High moisture content also makes the area prone to mold, fungi, termites and even rodents. It may also result in foul odors if left unchecked. Hence, crawl spaces need to be waterproofed. 

Professional agencies like Delaware Waterproofing from Delaware offer a one stop solution for all your waterproofing problems. They provide professional service and quality work for basement or crawl space waterproofing, drainage solutions, mold remediation and structural repair. You can judge an appropriate water proofing solution for your crawl spaces by getting in touch with them. 

Solutions to Manage Humidity Levels in Crawl Spaces

There are two solutions to waterproof the crawl spaces:

  1. Vapor Barrier Installation
  2. Crawl space encapsulation

Vapor barriers vs crawl space encapsulation

Vapor barriers are rolls of large plastic sheets placed on the ground to avoid the evaporation or condensing of moisture. They are also known as “vapor diffusion retarder” because they cannot seal off 100% moisture, but they are very effective in slowing down the process of decay due to excess moisture. 

The plastic sheets used are made of reinforced polyethylene plastic. Their thickness ranges from 6 mils to 23 mils based on your budget and requirements. One mill is equal to 0.001 inch. Thus, 6 mils is 0.006 inch. 6 mils are the minimum recommended thickness for installing a vapor barrier. 

Crawl space encapsulation seals the entire crawl space region with the walls with thicker sheets of around 10 mils or more. The entire area is cleaned, water is drained away with a sump pump, and dehumidifiers and the entire crawl space is sealed. The entire area is covered, including walls and the ground. This ensures a cleaner crawl space, which can also be utilized for storage purposes. It prevents water pooling in the crawl space area. 

However crawl space encapsulation can be done only by professional agencies. Overall, encapsulation is a very costly option. 

While considering which option better suits your crawl space, you can contact the Delaware Waterproofing through their website:

Cost of Vapor Barrier Installation in crawl spaces

Installing a vapor barrier in the crawl space is, on average, $1.35 to $2.00 per square foot. The total cost would be around $1500 to $4000 including labor and materials. The cost may vary depending on the thickness of the vapor barrier used and if any specific customizations are required for installation. 

You can get a free estimate for installing a vapor barrier in your crawl space through the website of Delaware Waterproofing. 

Benefits of installing a vapor barrier in crawl spaces

Vapor Barrier Installation prevents high moisture and dirt. If overlooked for a longer time, it can lead to seepages and leakages that require thousands of dollars as an investment. Thus, if you are considering installing vapor barriers in your crawl spaces, take note of its benefits:

  • Vapor barriers are comparatively a cheaper option than crawl space encapsulation. 
  • With vapor barriers the moisture does not seep up to the floors and walls of your homes. This protects the structural integrity and longevity of the building.
  • It protects from the growth of mold and mildew.
  • There can be a potential structural wood rot due to excess moisture in the crawl spaces. Vapor barrier protects from such incidences.
  • Due to moisture, there can be corrosion or rusting of wires and electrical connections in the crawl spaces, causing unnecessary wiring mishaps. But this can be considerably controlled by reducing the moisture. 
  • We can only keep the crawl spaces free of insects and pests if they are clean and moisture-free. 
  • Vapor barriers ensure proper insulation of the homes. This reduces the energy bills considerably. 
  • Crawl spaces become out of sight, out of mind while cleaning the homes. Installing vapor barriers ensures its cleanliness. Its maintenance becomes easy, and therefore, access to it improves.

The process of installing vapor barriers in the crawl spaces for humidity levels

If, after contemplating its costs and benefits, you decide to install vapor barriers in your crawl spaces, the process of installation is easy. Consider hiring professionals to do that. Or if you have time and want to save money on that, you may do the same yourself. 

  1. Create good drainage around the home so the rainwater does not stagnate or seep into the crawl space.
  2. Prepare the crawl space by clearing any extra debris, dirt, insulation or existing vapor barriers. It is always easier to work in a cleaner and free space. 
  3. Gather the required supplies- crawl space vapor barrier of an appropriate thickness (minimum 6 mil), measuring tape, utility knife, an adhesive or staple gun, hammer, straightedge and if required, gloves and masks. 
  4. Cover the crawl space with the polyethylene vapor barrier. Make sure to cover the dirt neatly. 
  5. Cover the place such that the sheet covers the entire place gradually and also covers a few inches up the side walls.
  6. Use the utility knife to cut the sheet rolls whenever required to accommodate the fittings and fixtures in the crawl space. A few holes will help drain the extra rainwater that gets collected.
  7. Use an adhesive to secure the vapor barrier to the area’s walls, piers and other surfaces. 
  8. Seal the edges, gaps and penetrations properly using an adhesive or tape to prevent further moisture seepage. 
  9. Cover the exterior of the foundation walls with moisture-proof insulation. It will ensure that the water does not seep into the crawl space. 
  10. Cover the interior of the foundation walls with the polyethylene vapor barrier used for the crawl space and galvanized flashing to prevent moisture from seeping in. 
  11. Check if any gaps or edges are loosened. Seal them appropriately. 
  12. Keep a watch in the crawl space area for a few months after installing a vapor barrier to keep track of any fresh moisture seeping into the crawl space. 

Problems of installing vapor barriers for crawl space humidity levels

  • Crawl space vapor barriers are not a foolproof solution for house moisture problems. But they are a good prevention against moisture from the ground soil to the floors and walls. 
  • If vapor barriers are installed by professionals, the finishing of the entire work is different. The entire crawl space region is properly covered with the vapor barriers of appropriate thickness that are neatly sealed at all the edges, gaps and penetrations. But if you install them yourself, it might turn out to be further cheaper, but due to lack of experience some edges or gaps might be left out. This would further lead to the wastage of all the installation efforts. 
  • When vapor barriers are installed as DIY projects, there is always a possibility of going wrong in the decisions about the right thickness of the required vapor barrier polyethylene sheet. Professional agencies would always suggest the best choice based on your specifications.  
  • Crawl space vapor barrier does not give a solution to water pooling. But it does not allow the pooled water to seep into the ground, walls and floors. 


Specific knowledge and techniques are required for Vapor Barrier Installation in crawl spaces. Therefore, consulting agencies like Delaware Waterproofing, with 30+ years of experience, would be advisable. Hiring professionals is a better option if you want a lifetime solution for all the water issues in the basement area. It might be expensive by a few dollars, but it is an investment to protect the house’s structural integrity and the dwellers’ health. 

Frequently asked questions

Q: Is there a need to install vapor barrier for crawl space humidity levels?

A: Yes, because it is an investment to prevent the structural integrity of your house or building and the health of its residents.

Q: Which is the best professional agency to install vapor barriers for crawl space humidity levels in Greater Delaware ?

A: Although many agencies are providing waterproofing solutions in the Delaware region, Delaware Waterproofing is a one-stop solution for all the waterproofing solutions for your basements and crawl spaces with a professional experience of 30+ years. 

Q: How long does a crawl space vapor barrier last? 

A: A properly installed vapor barrier lasts about twenty or more years. But in emergencies or special circumstances, it is better to consult professional agencies if the existing vapor barrier needs to be repaired or replaced. 

Q: How do I protect my crawl space from moisture? 

A: Crawl space moisture problems can be handled by installing appropriate vapor barriers in the crawl space or crawl space encapsulation. Vapor barriers prevent moisture seeping up to the floors and walls. But it does not prevent water pooling. Encapsulation is the complete sealing of the crawl space area after removing the moisture. It also prevents water pooling. 

Q: Is a thicker vapor barrier better?

A: A thin vapor barrier becomes permeable by water and moisture over time. Thus, the thickness of the vapor barrier must be a minimum 6 mil or 0.006 inches. However an appropriate thickness of the vapor barrier must be consulted by professionals as per the specifications.