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Open Vents

If your property has open or uncovered crawl space vents, you should rectify this quickly. Exposed vents are a leading cause of crawl space damage and unhealthiness.

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These days, newly built properties tend not to have crawl space vents at all, but will instead have a crawl space door or access hatch. Older properties tend not to have them, but if your home was built between the 1950s and 2000 (roughly), it is likely that it will have crawl space vents. Properties that have these vents tend to have them covered with durable PVC covers or doors, but this is not always the case, even in Cincinnati and Columbus, OH. 

If you live in a property that has open crawl space vents, we recommend you cover them as soon as possible to avoid damage and infestation within your home. 

Of course, you should have a professional assess your crawl space before you do to ensure you are not sealing in problems and pests. If you are concerned about the health of your crawl space and its effect on your home as a whole, however, full encapsulation or waterproofing could be the best option for you. This will not only address any damage in your crawl space but prevent it from recurring at a later date. 

A History of Crawl Space Vents 

Building codes and regulations are always changing. From year to year and state to state, properties must meet slightly differing standards. When it comes to crawl spaces, this can be a complex issue because of the gray area they inhabit. Too small to be considered a functioning part of a home, like a basement, but far too enclosed to be considered an exterior or separate space, crawl spaces can be a pain. 

Through the 1950s, it became best practice to install vents into a crawl space to increase airflow. This was believed to improve ventilation and prevent dampness and excessive humidity. However, this has since been proven to be untrue. In fact, crawl space vents are more likely to cause these issues than alleviate them. In the 1990s, studies found that crawl space vents not only allow dampness and moisture into a crawl space but that they reduce energy efficiency and can make it hard to maintain the temperature of your home. 

As a result, crawl space vents have been in decline for the last 20 years, and are now routinely covered as a part of general crawl space improvement work. Sealing crawl space vents is now recognized as a far healthier state of affairs (as long as air is artificially circulated) 

What Problems Can Open Vents Cause? 

vented crawl space with bad insulation

Of course, all of this is not common knowledge, which is why so many homeowners are shocked to hear that their crawl space vents could be causing serious problems in their property. There are many different issues that can arise as a result of having uncovered crawl space vents. They include, but are not limited to: 

High Relative Humidity 

Having your crawl space open to the elements via uncovered vents can have many different side effects for your home. This has a lot to do with the climate outside, of course, but just as much to do with the crawl space environment. While Cincinnati and Columbus, OH, are known for relatively warm and humid winters, it does not matter how warm the outside world is—a crawl space will generally be colder. 

As such, the relative humidity in an unsealed crawl space will tend to be high no matter the weather because of the way in which cold and warm air clash in this space. Thanks to the stack effect that is caused by the uncovered vents, this humidity spreads into the main property almost immediately and will start to have an impact on the internal climate quickly. 


When the relative humidity in a crawl space reaches 100%, condensation will start to form on the walls and even the ceiling of the crawl space. This will cause damage to any exposed wood in your crawl space and may cause it to start rotting. This is not only unhygienic and likely to cause a seriously bad smell but could lead to the collapse of the floor above your crawl space. 

Condensation can also occur throughout the rest of your home when your crawl space is suffering from 100% relative humidity on a regular basis. This will directly contribute to an unhealthy environment and secondary damage. 

Mold and Mildew Formation 

When your home has ongoing issues with dampness, humidity, and condensation, the formation and spread of mold and mildew is almost guaranteed. There are many different species of mold that can be found in Ohio, some of which are more dangerous than others. However, all of them have the potential to cause damage to your home and irritation to your skin, eyes, nose, and respiratory system. 

Black mold is undoubtedly the most dangerous form of mold that can spread in your home. Capable of causing serious irritation to your lungs, eyes, skin, and throat, this kind of mold is notoriously unhealthy. As well as causing headaches, dizziness, and skin irritation, black mold will exacerbate pre-existing medical conditions in a potentially lethal way. 

Pest Infestation 

Crawl spaces that have uncovered vents provide inviting environments for pests of all kinds. Rodents and insects, in particular, will find unsealed crawl spaces particularly welcoming and can easily and quickly set up nests that will allow them to spread through your home as a whole. From rats and mice to cockroaches and spiders, there are many pests that are native to Cincinnati and Columbus that you could find yourself dealing with if you don’t cover your open vents. 

Even if you have installed grates over your crawl space vents, you will find that some small pests can still make their way into your home. It will keep out very large pests, of course, but even smaller snakes and rats could still pass through certain grates. 


Unless you cover all open crawl space vents in a way that totally seals them, your home will be vulnerable to flooding during periods of heavy rain and flooding outside your home. This is more concerning than you might think because water that makes its way into your home from outside will not drain away when the flood recedes. 

Instead, the water will be trapped under your home until it is manually drained, affecting the humidity levels in your property and causing damage to the vital systems that keep your home running. 

As you can see, it is incredibly important to cover your crawl space vents before problems start to take root. It could save you a lot of time and money over your time in the property. 

Open Vents


Have you noticed a bad smell in your home that has seemingly no cause? Does it fail to lessen or go away no matter how much you clean? If so, it is very likely that the original source of the smell is in your crawl space somewhere. There are many things that can cause a crawl space to smell bad, including: 

Pest Infestation 

Crawl spaces are notoriously prone to pest infestation, especially when they have not been fully encapsulated. Some pest infestations are more pungent than others, of course. Spiders, wasps, and harvest mice, for example, will not make a terrible smell even if their nests are very large—unless one of the nests dies and begins to rot (in which case the smell will be quite strong and persistent). 

Other pests, however, can make a very bad smell without trying. Rat nests, for example, can produce a strong smell, as can cockroaches. In fact, depending on the type of cockroach and the size and age of the nest, a cockroach infestation can be actively dangerous to your health as well as bad smelling. Worst of all are larger pests that can make dens in exposed crawl spaces. 

Open Crawl Space Vents 

It may sound silly to say that open vents can contribute to a bad smell in your crawl space, but they can indeed. This is because of the way in which open vents allow moisture and dampness into your home. When the humid air from outside gets into a cool crawl space, for example, it can cause condensation and lead to water seeping into exposed woodwork. 

This can lead to persistent dampness, which will create a smell of its own but can also cause wood rot and allow mold and mildew to flourish. Rot, mold, and mildew can produce a strong and pungent smell that will spread throughout your home quite quickly. You will be able to recognize this smell thanks to its slightly oily edge. 

Covering your crawl space vents should be high on your priority list as a homeowner, but there are some things that you need to do before you can seal your crawl space vents safely. After all, you don’t want to shut in pests and problems. 

Sealing a Damp Crawl Space Creates an Incubator 

Durable, high-quality PVC crawl space vent covers can be purchased in most hardware stores. So, it is possible to simply buy vent covers and install them yourself. However, we do not recommend that you do this for a number of reasons. First, there is no guarantee that generic vent covers will fit your property’s vents well. If they do not form a full seal, water will be able to get into your crawl space and become trapped. 

This trapping of moisture or pests is the main problem that comes with simply covering your vents and calling it a day. You see, sealing your vents will prevent airflow from outside. That means that any moisture that becomes trapped will have nowhere to go. As a result, the environment will become an incubator for dampness, condensation, mold, and mildew. This will damage the structure of your home, but can also impact your health. 

Crawl Space Waterproofing Prevents Damage 

As you can see, it is important to deal with underlying issues in your home and crawl space before you simply seal the vents. This means handling problems like foundation damage, seepage, and other structural issues to ensure that your crawl space is in good health before you seal it up. The process of waterproofing will begin after all structural issues have been dealt with. 

Waterproofing your crawl space goes beyond simply sealing the vents, however. A typical crawl space encapsulation will include a process of drainage improvement and insulating before a vapor barrier is installed and the vents are covered. The installation of a dehumidifier is typically the last step in the process. Once your crawl space has been encapsulated, you will see a huge difference in the climate inside your home. 

While the process of waterproofing and encapsulation may seem straightforward, we urge you not to attempt it alone. This process uses many delicate pieces of equipment that can be easily damaged and will cause more harm than good if done incorrectly. 

DIY Jobs Can Go Wrong 

If you try to encapsulate your crawl space alone, you could very well find you do more harm than good to your home. If you install insulation and a vapor barrier in a crawl space that is damp because of foundation damage, for example, you will only cover up the signs of deeper damage. The damage itself will continue to grow until it presents itself in other ways, by which time it will be more expensive and difficult to repair. 

Likewise, if you install the wrong waterproofing measures, or choose an appliance that is unsuitable for your home, you could end up spending more money than you need to or leaving your crawl space not properly protected. This will, once again, cause or exacerbate damage to your crawl space by acting as an incubator for dampness and mold. As a result, the effects on your home and health will be magnified. 

Professionals Give the Best Results 

Having a professional undertake crawl space waterproofing may seem like an unnecessary expense, but there are many benefits to doing so. First and foremost, a professional will be able to assess your crawl space and identify all damage and its underlying causes. More than this, they will be able to repair the damage and create a healthy environment in your crawl space. This will give them the perfect base for waterproofing. Having this strong and healthy base before the encapsulation process will not only provide a better result; it will also protect the products and appliances that are put in place. 

When it comes to the process of encapsulation itself, professionals will be able to offer you a better result than a DIY process could. This is partly because of their experience and skill, but also because they have access to the best tools and products for this process. Industry-grade products and appliances are not always sold over the counter in hardware stores and can be hard to get ahold of when you are not a contractor. Even if you can find them, as a non-professional, chances are you will pay more for them. As such, professional crawl space encapsulation can actually be cheaper and will almost always be more cost-effective in the long term than a DIY job.

How to Protect Your Crawl Space 

Covering your open vents is not the only thing that you can do to take care of your home and create a healthy environment in your crawl space. The process of crawl space encapsulation has developed incredibly over the last 20 years. 

If you have a home with open vents, you should consider waterproofing your crawl space to protect your investment. There are many professionals across Ohio who will be able to help you. The process of installation goes like this: 


Most crawl spaces should have some form of drainage in place already, but if the drainage provisions in your crawl space are unsuitable, there are many options available. For example, you could invest in some drainage matting to allow water that gets into your crawl space a channel under the crawl space liner. 

Likewise, there are perimeter drains that can be installed to collect water as it seeps up from the ground and many different sump pump options for you to consider. Once you have proper drainage in place, the process of encapsulation moves to the next step. 


Installing insulation on the crawl space walls will make a huge difference to the health of your home. Insulation will help to provide a more regulated temperature in your home as a whole. Insulating your pipes will also prevent the likelihood of them bursting in a sudden cold snap and make your home’s plumbing system more energy-efficient, thereby saving you money. 

Vapor Barrier Installation 

Installing a vapor barrier is an incredibly important part of crawl space waterproofing that will leave you with a safe, dry, and hygienic space that can be used as extra storage. When it comes to crawl space encapsulation, you should contact a professional to ensure that you get the best and most durable vapor barrier for your home. 

Vent Covering 

Actually covering your open vents will be one of the last tasks during crawl space encapsulation and waterproofing. After all, it is important to make sure the space is safe, dry, and secure before it is sealed away. These days most vent covers and doors are made of durable, heat, and weather-resistant PVC plastic to ensure a tight seal and long-lasting protection. These covers are also customizable, so you can make sure they blend in with the exterior of your house if you want. 


Once a crawl space has been sealed, it is important that you install a dehumidifier to manage the internal climate and ensure that there is a healthy level of airflow around the space. There are many energy-efficient dehumidifiers on the market right now, but you should talk to a professional to make sure you get the right model for your home. 

Crawl space encapsulation and waterproofing are incredibly versatile processes that can be tailored to your specific needs by an experienced professional. Of course, we do not suggest that you attempt to encapsulate your crawl space alone. Having professional help will ensure that you get the best possible result at the best possible price. Finding the right crawl space specialist for you should be a priority. 

Ohio Basement Authority Offers Quality Crawl Space Encapsulation 

If you want to have your open vents covered, you have decided to go for full crawl space encapsulation, or you just want to talk to a professional about your options, it is time to call Ohio Basement Authority. We are experts in crawl space repair and waterproofing and have helped thousands of homeowners across Cincinnati and Columbus, OH. No matter what forces are at work in your home, our experienced and skilled team will be able to help you set it right. 

Whether you simply want vent covers installed to protect your home, or you think there may be structural issues at work, the process will start with a free inspection appointment. Our team will schedule this appointment for a day that suits your schedule and send an inspector to ensure that we understand the precise nature of the issues in your home. We will then provide you with a free, no-obligation estimate for all costs associated with our suggested work so you can make an informed decision about what is best for your home. 

Our crawl space experts can help you

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