The crawl space is usually the most-often ignored part of any house – it is, after all, a space that simply cannot be used for any purpose. What goes on in this place, however, can and does have a strong impact on your home and the health of its occupants.

Once upon a time, houses were built by contractors and carpenters who used their own wisdom and expertise but little to no building science. These builders had the good idea to create a space, like a miniature basement, beneath houses that were large enough for a person to crawl through. These crawlspaces made for easy access to utility lines and pipes while remaining less expensive than basements. During this time, the logic was that foundation vents would allow air to circulate all-round the house while also keeping a crawl space dry.

However, it was later discovered that open crawl space vents did more harm than good. Building scientists, who created an entire discipline studying the pros and cons of construction, determined that vents can actual do the opposite; promoting mold and decay by increasing moisture levels. This failure in functionality occurs because the moist, outside air typically condenses into water as it enters the vents –and we all know the damaging effects water can have on a home. After much debate and discussion, and a number of studies, this was finally established as a fact.

Nowadays, we know better and the science is there to back the facts. An open crawl space vent will allow the influx of moisture, which in turn make it a hub of mildew, mold spores, and an assortment of bugs. These open vents also reduce the energy efficiency of homes by allowing cooled and heated air to escape while outside elements creep in.

The best solutions to this issue is to make sure crawl space vents are properly sealed. Given the fact that over 50% of household air actually flows up from your crawl space, it is very important that this problem get fixed soon – something that can only be accomplished with sealed vents.

Similar to a full-sized basement, crawlspaces can have leaks and other moisture problems aside from the ones caused by open vents. A full crawlspace inspection and encapsulation should be considered.


An increasingly popular way to avoid indoor moisture problems, crawl space vent sealing is very similar to the lining which is added to swimming pools to prevent leaks. The goal, here, is to prevent moisture from forming in foundation vents and the crawlspace itself by putting a barrier in place.

The process of sealing crawl space vents involves installing a heavy-duty polyethylene barrier over the floors and foundation walls of the crawlspace. The barrier is then sealed with tape which also serves to connect all the barrier pieces. Once the sealing work is done, the air inside the crawlspace can be properly maintained by installing a dehumidifier which will remove excess moisture in the air as it appears.

This combination of using a barrier and a dehumidifier serves to protect the crawl space from too much moisture and all problems that come with it.


Sealing crawl space vents has several benefits, which include:

  • Creating an atmosphere that does not allow the growth of any kind if mold, mildew bugs or pests
  • Better quality of air in both your crawl space and your home
  • No rot resulting from water, fungi and mold
  • Helps to maintain a secure foundation
  • A home that is more energy-efficient, due to you not having to tackle vent-related problems; and
  • More potential for extra storage


Much like everything else, many people believe in DIY-ing the task of sealing their crawl space vents to cut back on costs. While it is certainly possible to do so, the results may not be so long-lasting, especially if done by beginners and amateurs. It’s also worth noting that whoever does the job is likely to run into some surprised, like poisonous snakes, bugs, and rodents.

It is always best to hire a professional company that is also able to seal your crawl space for you. Not only will they follow proper procedure and work with a far better level of efficiency, they will also address any other moisture or foundation issues in the area. For additional energy-savings and comfortable, contact Carolina Crawlspace Pros – basement waterproofing, crawl space encapsulation and spray foam insulation services you can trust.