Your Guide on How to Seal Crawl Space Vents

Are you looking for more information on how to seal crawl space vents? Do you want to know how to seal your crawl space on your own?

Sealing off your crawl space is extremely important, especially if you live in an area with a lot of humidity or if you live in an area where it becomes frigidly cold in the winter.

You came to the right article if you are looking for more information on sealing off your crawl space area. We will go over how to seal your crawl space and who you can contact for help!

Why Seal Your Crawl Space Vents

The outside air is humid, which creates a significant amount of moisture. This warm and humid air creates condensation when it enters through your vents into your crawl space. Once this moist air hits the cooler surfaces in your crawl space, it creates an environment for mold and mildew to grow.

Not only is this mold bad for you and your family’s health, but it is also bad for the structure of your home. The mildew and mold can spread to any nearby belongings, and it can damage your insulation. 

Save On Your Energy Bill

The frigid cold air can seep through your crawl space vents in the winter, creating cold floors. In addition to these cold floors, it can also cause uncomfortable drafts, forcing you to need to crank up the heat to compensate for the cold. The more you need to use your heater, the higher your utility bills will be. 

Prevents Rodent Infestation

Rodents looking for shelter will enter through your vents, and they will nest in your insulation. As they nest and reproduce, they cause damage to your insulation.

These rodents not only cause damage to your insulation but also leave droppings along the way. The idea of mold, mildew, rodents, and rodent droppings festering in your crawl space should be more than enough for you to want to learn how to seal crawl space vents for winter. 

Vented vs. Unvented Crawl Spaces

All crawl spaces are not the same, and this depends on where you live and the age of your house. For example, an Arizona home in the 1950s is more likely than not to have a different crawl space makeup than a newer build in Seattle.

Homes in built-in warmer climates, such as Arizona, don’t need crawl space vents because the dry soil and sunny weather take care of handling excess moisture in the home. 

Homes built in humid areas require proper ventilation more than those in warmer and dryer climates. Water in your home is the leading cause of problems in your crawl space, and adequate crawl space ventilation and insulation can help prevent water buildup. 

Home Age vs. Crawl Spaces

Houses built in the 1940s and 1950s had little to no insulation in the crawl spaces, making it more expensive and more difficult to heat homes. During that time, most homes had an R-11, which is currently below today’s building codes.

According to, the R-value measures the home’s ability to prevent the transfer of heat. The larger the R-value number is, the more effective and efficient the home’s insulation is.

Currently, the roof on your home should have a minimum R-value rating of R-30. Anything less than that means that your insulation needs inspecting. 

How to Seal Crawl Space Vents

Knowing how to seal off crawl space vents in your home is one of many approaches you can take to prevent any unwanted moisture from entering your home. Although sealing your vents is an effective way to keep air out, it won’t stop any moisture or air from entering through gaps and cracks in your crawl space.

Address Any Moisture Issues

If you have any standing water in your crawl space, you must address and handle this first. A sump pump and a drainage system will help in removing any sitting water.

This system will collect and pump any water out from your crawl space and away from your home. Make sure that you also examine your ductwork to see if there are any leaks. If there are leaks, you must seal the ductwork at the seams. 

Crawl Space or Basement Encapsulation

Once you have addressed and handled your moisture problems, it’s time to air seal your crawl space or your basement. Air sealing your crawl space ensures that there are no open gaps.

Once this is complete, you can install a sturdy vapor barrier on the walls and floor of the crawl space. This vapor barrier is a thick plastic material that will help prevent moisture from entering your space. 

Crawl Space Dehumidifier

The most vital and very last step you need to take is to install a crawl space dehumidifier. This dehumidifier ensures that the humidity level in your crawl space stays at a constant and acceptable level. 

Install a French Drain

This step is optional, but you may need a French drain if you have a consistent water issue in your crawl space or along your home’s foundation. You may want to consider installing a French drain even if the water issue is seasonal. 

Crawl Space Encapsulation vs Insulation

Many people confuse crawl space encapsulation and crawl space insulation, but these serve two different types of functions. Crawl space encapsulation works well if you are dealing with ground moisture and humid air, whereas crawl space insulation mainly deals with controlling cold floors. 

Crawl Space Encapsulation Cost

The average cost for a crawl space encapsulation job is around $7,000. Some other crawl space encapsulation jobs can go as high as $30,000. There is no need to worry about the cost of the job. The rate of the service depends on the size of your crawl space. 

Other factors that affect the cost are:

  • The condition of your crawl space
  • The contractor working the job
  • The type of material used for the job

To figure out how much it will cost for your home, you will need to reach out to a few companies for quotes. Ensure that the companies you look into have the proper licenses and certifications to do the job right. 

Choosing the Right Contractor

DIY home repairs and upgrades are cost-saving and fun for many homeowners, but it is best to reach out to a professional for some assistance when it comes to your crawl space.

Working on your crawl space on your own is not an easy feat, especially if you lack the necessary skills to complete the job on time and on your own. You can risk wasting a lot of time, money, and effort if you try to repair your crawl space without the proper tools and techniques. 

Best Crawl Space Vent Repair

Although most crawl spaces share the same issues, every home is unique, so it is best to have your crawl space inspected by a Crawl Space Medic technician.

Every technician at Crawl Space Medic has the proper certification needed to inspect and repair your crawl space vent issues properly. Because your house is unique, each technician will take an individual approach to your home to find the best solution for you. 

Why Hire a Professional?

As mentioned earlier, DIY projects can be fun for homeowners to do, but you should bring in a trained professional to do the work on your behalf. Hiring a professional will save you a lot of money because these professionals know exactly what they need to do to get the job done. They will also get the job done sooner because they specialize in crawl space vent repairs.

Another benefit of hiring a professional is that you don’t have to worry about replacing the encapsulation for a while once the job is done. Most companies offer you a warranty on the repair as long as no catastrophic events ensue. 

Crawl Space Vent Experts

Now that you know how to seal crawl space vents, it is time to get to work! Although you have the option to seal off your crawl space on your own, it is not recommended to do so if you don’t have the proper experience.

Reaching out to a professional not only saves you time but can also save you a considerable amount of money. Check out our website if you are looking to submit a quote to find out how much it will cost to repair your crawl space. We offer financing options if needed and our inspections are free!


Related Posts

Will Insurance Cover the cost of Encapsulation?

Why Are My HVAC Ducts Sweating?

Understanding the Stack Effect

Encapsulated vs. Ventilated Crawl Spaces: A Comprehensive Guide