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Crawl Space Vent Covers

Crawl spaces are prone to moisture issues in the way they were built. Sealing your crawl space with vent covers will help you avoid this problem.

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While your property’s crawl space is never going to be the most inviting part of your home, it is important that you keep it as clean, dry, and tidy as possible to avoid problems developing without being detected. 

Covering your crawl space vents is just one way in which you can do this, and it’s so easy. In fact, there’s really no reason to avoid installing properly fitting crawl space vent covers, especially if you want to avoid dampness problems.


Why You Need Crawl Space Vent Covers 

Crawl space vents are found in many older homes, and they were initially installed because they were believed to prevent or minimize dampness problems. The rationale was that by increasing airflow, these vents would lower humidity. Certainly, crawl spaces themselves were put in place to protect properties by keeping the home slightly above the ground while allowing access to key systems without pulling up floorboards. 

Over time, however, we have realized that crawl space vents can cause more harm than good if they are not properly covered and cared for. By letting in water during periods of heavy rain, humid air during the summer, and freezing air during the winter, vents make your crawl space susceptible to dampness, mold formation, and pest infestation. 

This is because the air in your crawl space will generally be cold, or at least cool, even in summer. When the humid, warm air comes in, condensation will form on the wood and other materials in your crawl space. This will attract pests and allow mold to form. In winter, it will continue to collect dampness and be more susceptible to snap freezes. Covering your vents properly, however, can offset these issues while still allowing external access when needed. 

The Benefits of High-Quality Vent Covers 

Covering your crawl space vents properly offers a range of benefits to your home as a whole. The most obvious benefit is that well-fitting, high-quality covers will help prevent dampness, mold, and pests from getting into your crawl space to wreak havoc. Properly fitted and sealed vent covers will: 

  • Keep out rain 
  • Stabilize your crawl space climate to avoid condensation and dampness 
  • Deter pests like mice, rats, and raccoons from entering your crawl space 

As a result, you will find that your crawl space is clean, dry, and safe, especially when paired with other crawl space solutions like vapor barriers and dehumidifiers. Better still, you can rely on it staying that way unless the covers experience damage or the weather becomes incredibly severe. This will, in turn, minimize and prevent problems in your crawl space and home as a whole. In fact, it could even save you money on your energy bills by stabilizing the climate and making the temperature in your crawl space and home easier to control. 

Vent Covers


It is wise to cover your crawl space vents. Crawl space vents are now known to allow moisture and pests into your crawl space. This can cause problems with dampness and mold, but also make it hard to control the temperature and climate in your home. 

  • Keep Out Dirt and Dampness 

Vent covers keep water and dirt out of your crawl space by covering up the most vulnerable points of your crawl space. This has many benefits in the long term, of course, as well as in an immediate sense. Keeping dampness and dirt out of your crawl space is one of the most effective methods of preventing issues like mold and mildew formation, wood rot, and sagging floors. 

This prevents many different, more serious problems from taking root in the first place. Structural issues like bowing walls or gaps between walls and flooring can start with dampness and wood rot. With this in mind, it is a good idea to invest in high-quality vent covers as a matter of course; it could save you a huge amount of money and stress in the long run.

  • Ward Off Infestation 

Crawl space vent covers reduce the chances of infestation by blocking off the large points of access for insects and rodents. Of course, it doesn’t make infestations impossible, but it will prevent many avoidable instances. This is positive for a number of reasons, of course. First and foremost, pests in a home are unsightly and unnerving for many homeowners. Keeping pests out will provide you with a more enjoyable living environment. 

Of course, it will also be a healthier living space. After all, certain kinds of pests can cause damage to your property and health if left unaddressed. Cockroaches, for example, are incredibly unhygienic creatures whose droppings and shed husks carry huge numbers of germs. A prolonged infestation of cockroaches can lead to sickness, skin infections, and respiratory issues.

If you leave your crawl space vents uncovered, you could face a number of issues. First and foremost, heavy rain could lead to flooding in your crawl space. Even if you avoid flooding, you could face problems with dampness, mold, and pests as a result of leaving your crawl space vents uncovered. Common problems caused by uncovered crawl space vents include: 

  • Dampness and Humidity 

By letting water into your crawl space, crawl space vents actually increase humidity, which can lead to a number of problems, including damage to your support joists. While the most obvious cause of dampness and humidity in an unsealed crawl space is heavy rainfall and flooding, the most common is actually a little more insidious than that.

Condensation occurs most often in the summer when warm, moist air hits the cool surfaces in your crawl space. This can cause a huge increase in humidity as well as allowing for the formation of mold and mildew in your crawl space. Over time, this humidity and the mold spores will travel into your house as air circulates through your HVAC system, causing more widespread issues. 

  • Structural Damage

Excessive and prolonged dampness can cause a lot of issues, but the most worrying is structural damage to your floors and the wooden joists that support them. Wood is extremely susceptible to dampness unless treated, and when it is exposed to prolonged periods of dampness and humidity, this can cause it to start rotting. Rotten wooden joists are a serious issue for any home. 

As wood rots, it becomes soft. This means it loses its ability to support the structure of your property and can start to bend or even crumble. Likewise, your wooden floorboards could begin to sag and warp, partly as a result of their own reaction to dampness, and partly because of damage to the joists that support them. The most noticeable sign of this kind of damage is a feeling of springiness or bouncing underfoot when you tread on affected flooring.

You can buy and install crawl space vent covers by yourself, but that’s unwise. Professionals like the technicians at Foundation Recovery Systems are guaranteed to choose the right vent covers for your home, and they will make the installation process easy. Better still, they will be able to spot existing problems in your crawl space. After all, there’s no point in sealing pests or dampness into your crawl space where the problem can grow unchecked. The benefits of professional installation are: 

  • High Quality 

Crawl space specialists have access to some of the best materials and will be able to provide crawl space vent covers that are not commonly found in hardware stores. These will fit perfectly and be incredibly durable, ensuring that you can kick back and relax without any worries about avoidable issues plaguing your property. 

Letting a professional supply you with high-quality vent covers will also ensure that you save money in the long run. Durable, well-fitting PVC crawl space vent covers, for example, have a life span of roughly 20 years (or even more). This means you won’t waste money replacing cheap vent covers repeatedly as they become worn or inefficient. 

  • Efficiency 

Installing vent covers may be straightforward, but there is a knack to getting it right. If you don’t get a cover that fits properly, or you fail to install it properly, you could see many issues within your crawl space and property at large. This is because poorly fitting vent covers will let moisture in while minimizing airflow, thereby exacerbating the issue and leading to severe humidity, mold problems, and musty smells throughout your home.

A professional, however, will be able to get the job done in no time at all with no hiccups or mishaps. This will save you money on unnecessary repairs and replacements in the future, minimize your stress, and free you up to deal with other things. So, as you can see, allowing an expert to take care of your crawl space vent covers is a small act that could have a big effect!

Choosing the Right Covers 

Of course, an ill-fitting or unsuitable vent cover is practically as bad as having no cover at all. In fact, it could be worse; if your vent cover is letting in dampness as well as blocking outdoor airflow, your crawl space will become a breeding ground for mold and mildew very quickly. Here are some things to keep in mind when considering what kind of vent covers to have installed. 


Vent covers come in many different forms, so it is important that you choose the right kind of material for your climate. Missouri can be very humid, and the temperature can change dramatically, which can cause damage to crawl space vent covers. Materials like plastic are best because these covers are lightweight, durable, and waterproof. Consider durable and weather-proof covers when thinking about long-term protection as these covers are by far the most cost-effective and efficient on the market right now. 


Make sure you get exactly the size of cover that you need; a good fit is essential to efficiency. If the cover is too small, you will have problems fitting it and it could easily come loose or allow moisture and pests into your home. If the cover is too big, the sealant could fail or there could be spaces between the vent and the cover that allow moisture into your crawl space. 

Installation Requirements 

It’s important to choose vent covers that are easy to install and remove when you need access to your crawl space. The best thing you can do is contact a professional who will be able to source and install high-quality, well-fitting crawl space vent covers easily and quickly. This may seem like an unnecessary expense when you could do it yourself but doing so could save you time and money in the future. 

Why Foundation Recovery Systems Should be Your First Choice 

Foundation Recovery Systems has been helping Missouri homeowners waterproof their basements and crawl spaces since 1992. We know a thing or two about getting the best results, and we know how to spot an issue before it becomes a real problem. If you have any pre-existing problems, such as mold or dampness, our technicians will spot and fix them. 

Our CrawlSeal™ crawl space vent covers are high-quality, durable, and easy to remove and replace after installation. Most importantly, however, they attach mechanically to provide an airtight seal around each vent. This means they help weatherproof and waterproof your crawl space by keeping rain, dirt, and wildlife exactly where they belong—in the yard. 

There’s no point in sealing off your crawl space if we are simply sealing in existing problems. Foundation Recovery Systems offers free inspection appointments to all homeowners to ensure that we know exactly what you need. This means that we will check for existing dampness, mold, or pest problems and suggest fixes before we install your vent covers. While this might seem like it’s making the job bigger than you expected, it could save you money in the long run by avoiding escalation. Our experts service homes in St. Louis, Kansas City, Moberly, Des Moines and Springfield.

Our Service Areas

Des Moines Location

2401 SE Creekview Dr.
Ankeny, IA 50021

Kansas City Location

7280 NW 87th Terrace, Suite C-210
Kansas City, MO 64153
(816) 774-1539

Lee's Summit Location

211 SE State Route 150
Lee's Summit, MO 64082
(816) 774-1539

Moberly Location

1401 US-24
Moberly, MO 65270
(660) 202-8662

Springfield Location
1820 N Barnes Ave
Springfield, MO 65803
(417) 612-8286
St. Louis Location

1625 Larkin Williams rd.
Fenton, MO 63026
(314) 207-9995