Should a Crawlspace Be Ventilated or Sealed?

This finished, sealed crawlspace is kept free of outside moisture by vapor barrier linings and a crawlspace dehumidifier
Thanks to vapor barrier linings and a crawlspace dehumidifier, this sealed crawlspace is made safe, dry, and usable!

Did you know that up to 40% of the air in your home is swept upwards from your crawlspace? When we think of our crawlspace, we don’t really think much of it aside from it creating a space between the earth and our home. It should be fine the way it is, right? That’s how it was designed, right? Unfortunately, it is not quite the case. When left alone, crawlspaces can become damp with outside moisture. Which in turn can lead to further complications within your crawlspace and the rest of your home.

But what’s a little humidity or outside moisture? If that doesn’t bother you, you might want to consider what else comes with that crawlspace air. When a crawlspace becomes dirty, damp, and musty with mold, all of that is being carried up into your home by that upward draft.

So how can you solve this problem? What can you do to preserve the quality of your home’s air? People may have once thought that crawlspace vents should be kept open during the summer. Vents should be closed during the winter. However, new wisdom says that crawlspace vents ought to be kept shut all year round to prevent the outside elements from getting into your home.

Let’s take a look into whether you should ventilate your crawlspace or have it sealed!

The Benefits and Problems with Ventilating Your Crawlspace

Depending on the size of your home, your crawlspace may have a few or a fair number of vents. These vents often look like small windows, and usually, they’re not very good at seeing through. Their main purpose is to supposedly help fight back against mold growth by allowing the air to circulate and ventilate. The concept goes: the fresh air comes in one way, and the fresh air pushes the stale air out through another vent.

Benefits of Ventilating Your Crawlspace

This kind of crawlspace ventilating is designed to go along with many building codes and is also the more affordable option to have when building a house. Also, if you’re in an area with a dry climate, there’s little to worry about moisture getting trapped in your crawlspace.

Problems with Ventilating Your Crawlspace

‘58 Foundations & Waterproofing President, Todd Prosan, states that “Depending on the state and area that you live, especially if you live in areas with higher humidity, ventilating can do little good for your crawlspace and the rest of your home. That’s because the humid air in your home is simply being replaced by more humid air from outside. With the consistent humidity, mold growth can occur in your crawlspace whether or not it’s ventilated.”

Termites require moisture and damp wood to start a colony, but a sealed crawlspace can keep that necessary moisture out
Termites love damp crawlspaces. A sealed crawlspace means not enough moisture for termites to survive.

Here’s a list of the common problems that a vented crawlspace can bring to your home…

  • Mold growth
  • Wood rot on your wooden structures including floor joists and support beams
  • Moisture-loving pests like termites and dust mites
  • Increased humidity can lead to increased energy costs on your heating/cooling
  • Rusting of metal equipment in the crawlspace
  • Allergens from outside can enter your home through a vented crawlspace

These problems won’t stay in your crawlspace either. Due to the Stack Effect (also called the chimney effect), any excess moisture and allergens in your crawlspace will be sucked up into your living space like a vacuum. Mold spores will get spread throughout your home in the process, making other parts of your home vulnerable to mold growth and wood rot should there be enough moisture present.

The Benefits and Problems with a Sealed Crawlspace

The signs are now pointing to building codes moving in favor of sealing your crawlspaces to protect them. Encapsulated crawlspace are consistently better at controlling moisture. In turn, the air quality drastically improves for both the crawlspace and your home’s living spaces.

In order to seal your crawlspace, you’ll first need to get rid of the existing moisture in there. Any standing water needs to be removed, and the space should be dehumidified before sealing measures are installed. Once ready, a vapor barrier will be installed and placed across the ground of your crawlspace, the support beams, and even the walls. You may also want to have your crawlspace insulated, and also waterproofed with drainage channels, and a sump pump with a battery backup. Ultimately, sealing your crawlspace is meant to help maintain a desirable environment in your house using a closed system approach.

Benefits of a Sealed Crawlspace

With a sealed crawlspace, your house can begin to benefit from a more closed system. If the air in your crawlspace is kept consistently dry, the air in your house will remain that much more comfortable and healthier for you and your loved ones.

If your crawlspace is insulated as well, it can improve the energy efficiency of your home and save costs on your heating and cooling. When your crawlspace is filled with humidity and moisture, it can place more stress on your home’s furnace and HVAC.

Keeping your crawlspace sealed and dry also creates an environment that has a greatly reduced risk for mold growth. Mold requires moisture to thrive. Without that moisture your wooden structures will be able to last for much longer and retain their structural integrity. An encapsulated crawlspace will also provide passive protection against radon gas that may be seeping up from the soil in your crawlspace.

Problems with a Sealed Crawlspace

Most homes don’t start with a sealed crawlspace. This means that you will usually have to seal your crawlspace yourself, which means costs. The encapsulation and sealing process can be on the expensive side, so it requires some financial preparation. What’s more, you will want to consider having maintenance done on your new crawlspace encapsulation once it’s in place, to ensure that it’s working throughout the years.

Keep Your Crawlspace Dry and Healthy with ’58 Foundations & Waterproofing

Sealing your crawlspace can be costly, but for the health and safety of you and your loved ones, it’s a more-than-worthwhile investment. A sealed crawlspace can spare you from the repairs that would be required when your home’s wooden structures become affected by moisture and mold. Mold spores can also aggravate existing allergies and health problems that you or a loved one may have. Preventing mold from gaining a foothold in your crawlspace should be a priority. Using a crawlspace dehumidifier can also provide an extra layer of protection against moisture in your sealed crawlspace.

’58 Foundations & Waterproofing has over 60 years of experience in encapsulating crawlspaces, repairing foundation walls, and removing mold from homes like yours. Our crawlspace repair experts will keep your home safe from the dangers of mold and moisture invasion. Give us a call today and let our experts provide you with a free inspection and a detailed estimate!