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Open Crawl Space Vent

Open crawl space vents are a huge contributor to crawl space unhealthiness. What should you know if you have open crawl space vents?

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Open Crawl Space Vents

When you’re looking for a way to maintain your crawl space’s health, you want to make sure you’re thinking about a variety of elements. One thing that you should think about relatively early in the process is open crawl space vents. When you have open crawl space vents, you’re essentially inviting a lot of problems into your home. Why is this such a big problem? Here’s everything you need to know about the issues with open crawl space vents.

Why Are Open Crawl Space Vents So Bad?

Some homeowners feel shocked when they learn that open crawl space vents are bad in the first place. Why are these vents so bad? What’s the big problem? There are several concerns that open crawl space vents can introduce, but here are the most obvious ones.


  • Relative Humidity 

Likely the biggest problem with open crawl space vents is relative humidity. Relative humidity is the one you’ll hear about when you turn on the weather. The metric measures how much water is in the air relative to how much water the air could hold. When it hits 100%, you’ll end up with condensation.

How does this have anything to do with open crawl space vents? Cold air can hold much less moisture than warm air. When you have open crawl space vents, you’re allowing cold and warm air to collide, and regardless of whether the cold or warm air is on the inside or outside, you’re going to end up with relative humidity reaching 100% either way, causing condensation to form in your crawl space.

  • Outside Water and Air 

Open crawl space vents also allow for water and air to come inside your crawl space freely. Neither of these is great. Your crawl space should ideally have as little outside interaction as possible. Instead of having outside water and air coming inside your crawl space, you want to make sure your crawl space stays dry and utilizes only conditioned air.

When you allow outside water and air in your crawl space, you’re much more likely to end up with a flooded crawl space and an air conditioner that’s working overtime. Remember, your home’s air comes largely from the crawl space, with as much as 50% of your home’s air having spent time in the crawl space at some point, so it’s important to keep that air healthy.

  • Rodents and Pests

Another giant problem that may arise due to crawl space vents is rodent and pest infestation. Because your crawl space tends to be enclosed and safe from the elements, rodents and pests will come inside if you give them any area to do so. That makes it very difficult to maintain open crawl space vents without pest infestations.

Even if you have a grated crawl space vent, you’re still going to end up with rodents and pests in the crawl space. A grated crawl space vent certainly won’t help you with smaller pests like gnats and flies, and it might not even help with some smaller predator pests like snakes and rats that might be in your area.

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How Do You Maintain a Healthy Crawl Space without Crawl Space Vents?

Many homeowners believe that open crawl space vents are the only way to maintain a healthy crawl space, which means they may never have even considered closing them. Here’s how you can make sure your crawl space stays safe and healthy even without open crawl space vents.

  • Crawl Space Encapsulation 

If you have a dirt crawl space, you need to invest in crawl space encapsulation. Essentially, crawl space encapsulation allows you to completely remove entrances for air and moisture from the outside of your crawl space. That makes it easier for you to maintain a healthy crawl space as a generalized concept.

Typically, a crawl space encapsulation process requires a crawl space vapor barrier, covering crawl space vents, and ensuring that all crawl space doors have effective seals. You may need more or fewer of these steps, depending on the problems you’re currently having with your crawl space and the issues you’re hoping to tackle.

  • Crawl Space Dehumidifier 

A crawl space dehumidifier can be a necessary addition to your crawl space, especially if you already have very high levels of humidity in your local area. Because crawl spaces sit underneath the ground, they’re often cooler than the rest of the home. Cool air can hold less moisture than warm air, which means that cool areas might have a high level of humidity.

The answer to this problem can be a crawl space dehumidifier. However, you mustn’t just add a crawl space dehumidifier into the crawl space without tackling any other problems first. You can’t just count on a crawl space dehumidifier to help you stay safe if you’re not willing to maintain your crawl space health in other ways.

  • Crawl Space Insulation

Insulation will help your crawl space stay healthier no matter what the temperature outside is. Unfortunately, if you don’t have great crawl space insulation, you’re going to end up with issues regarding your home’s temperature because the outside temperature will start to leak in through your home’s crawl space.

Again, it’s important to remember that crawl spaces have a huge impact on the rest of your home. When up to 50% of the air in your home comes from the crawl space, you want to make sure your crawl space is healthy and at the right temperature. Crawl space insulation can be a straight shot to doing just that.

FAQs About Open Crawl Space Vents

Many homeowners wonder why their home has crawl space vents if they are bad for the crawl space. After all, why would the construction crew build the crawl space vents in the first place if they are bad? There are a few main reasons that crawl space vents still exist in homes, even newly-built ones.

  • Tradition

The most common answer is that homeowners used to think that crawl space vents were good. The idea was that the vents would allow outside air in, drying and airing out the crawl space. In an ideal situation, this would prevent the growth of mold, wood rot, and infestations that are a result of a build-up of moisture and humidity.

However, nowadays, homeowners know that crawl space vents tend to cause significant issues. Instead of preventing moisture and humidity issues, they can cause them. Likewise, this makes a vital area of your home mostly exposed and vulnerable to the elements, so any flooding, drastic temperature changes, or drifting mold spores in the area can find an easy route in. Because of that, crawl space vents are waning in popularity.

  • Building Codes

Even though many homeowners know that crawl space vents aren’t great for the crawl space, building codes in many areas still require them. After all, legislation on these matters takes a long time to process, and even if local crawl space experts understand the value of more updated methods from on-the-job experience, it may be easier for regulators to simply stick with what’s tried and (supposedly) true.

Likewise, if there’s an option for an unvented crawl space, it often requires much more work. Some construction crews would rather just build the unvented crawl space, then allow you to fix it later if you want. This allows them to save on building costs and construction time but also works for homeowners who aren’t as invested in the process and would also like heavier costs to be an optional thing down the line. Thankfully, now that you are aware of the damage it’s causing, you can get ahead of the issue.

Putting a cover on your crawl space vents won’t necessarily fix the problem. Even though the main problem here is that the vents allow access to the outside world, there’s more to this problem than just that. Simply adding a cover yourself is unlikely to be effective.

  • More Elements Necessary

It can be tempting to just put a cover on the crawl space vents and call it a day. Although this could be an option, it’s not a great thing to do when you’re trying to DIY your crawl space vents. Any existing problems in the crawl space will need repairing, and additional solutions may be necessary to fortify against vulnerabilities that have developed in your home as a result.

Specifically, you need a lot more than just a cover to make sure your crawl space stays healthy after you close your crawl space vents. By trying to clear things up with a surface-level fix, you’ll have a few weeks or months of peace at best. After all, you may run into secondary issues that require more serious measures anyhow. 

  • Getting Help from an Expert

Putting a cover on your crawl space vents isn’t the only fix you need. You should also have a professional look over the situation and make recommendations based on your exact circumstances. They may be able to spot warning signs of other issues, or they can recommend more clever fixes that will give you a long-term solution, not just an easy one. For example, maybe a standard cover will only fix the problem temporarily, while more specialized crawl space vent covers can give you better access to your crawl space later or help to regulate issues with humidity.

Aside from that, they can help you find the most cost-effective solution. Homeowners that are tempted to simply buy vent covers and install them personally will find the results are more prone to errors, may be poorly fitting or the wrong design for their home, even if it doesn’t immediately appear this way. A professional will be able to help you pick the right design, install it properly, and provide a quality guarantee for one fixed price.

Some homeowners wonder whether crawl space vents that you can open and close on your own are a good solution. Although these might be a step up from the typical crawl space vents, they’re not the best choice.

  • The Purported Benefits

The main benefit that this type of vent offers is you can close them when bad weather is on the horizon. This ensures you don’t have issues with flood water coming into your crawl space, which you will if you have a crawl space vent that doesn’t close.

This also gives you the chance to balance the pros of crawl space vents with the cons. You can leave them open to air out the space and gain limited access if you need to perform pest control measures. It’s not complicated to open and close them when you want. 

  • Issues with These Vents

The main problem with these types of vents is that most homeowners forget to close them. It’s very easy to leave them open for several days or weeks at a time, which counteracts the entire point of the covers. During this time, pests can easily get in and out, infesting the area when the covers are open and thriving inside while the covers are shut.

Plus, floodwater isn’t the only problem that these vents face. They’re still prone to the same problems as all home vents, including issues with airflow and high crawl space humidity, which means you shouldn’t rely on them. They certainly won’t fix the problem all on their own and their few benefits might outweigh the dangers they pose.

When you have open crawl space vents, you’re going to have problems. Fixing those secondary problems, which can include things like high humidity, requires that you fix the open crawl space vents themselves. Here’s how you can avoid these problems overall.

  • Close the Vent for Good

Your best option for avoiding crawl space vent problems is to make sure you close the crawl space vents for good. Depending on how old your home is, or how the vents were designed, they may be open by default, leaving your crawl space vulnerable without your knowledge. As a result, the area is easy to access by the elements, pests, and other outside issues.

Closing the vent will fix many of the problems. It will prevent access by pests, which could otherwise find entry to the crawl space itself, but also your main home. You can rebalance the humidity or overall temperature in the area, which can affect your electricity bills. You can even safeguard the crawl space against flooding or water damage. While it won’t fix every issue, sealing the vents will prevent many. 

  • Talk to an Expert

You’re going to need to talk to an expert. That’s because these problems require very specific help to fix. If you try to apply a catch-all solution, you may find that it doesn’t last long or that it leaves room for other problems to simply develop out of sight. Likewise, DIY fixes are prone to costing more money and leaving you with damage that needs professional assistance anyhow.

A Groundworks crawl space repair expert can help you understand what’s going on in your crawl space. With a free inspection, you can then identify all the current problems with your open crawl space, catch warning signs for related issues, and prepare for any future problems that might develop. This can make it easier for you to maintain a healthier crawl space overall.

Fix Your Open Crawl Space Vents by Enlisting Help from a Groundworks Expert

When you want to fix your crawl space vents, you need to make sure you’re going about it in the right way. Sure, you could just put some vent covers on the crawl space vents and call it a day, but that’s not going to tackle all the problems in your crawl space. Many possible concerns might arise and you must talk to a Groundworks expert to find out more about your crawl space options.

From crawl space encapsulation to just installing a crawl space dehumidifier, there are many different options for your crawl space that can make it healthy and safe. For help closing your crawl space vents, talk to a crawl space repair expert to learn more about your options.

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