Open Crawl Space Vents

Do you have issues with open crawl space vents? Identify the causes and learn how our crawl space repair services in Colorado can fix the situation.

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Crawl space vents may seem like a good idea, and that’s why they’ve been installed on many homes, especially older homes. Leaving them open supposedly helped with airflow and improved the conditions of your crawl space. 
Sadly, homeowners are now discovering that open crawl space vents are breeding grounds for mold, pests, and other problems. By looking out for what kind of damage your own vents are causing and understanding why, you can bring your home back into safe working order. 

crawl space vents

Why Are Open Crawl Space Vents Disruptive for Your Home?

Open crawl space vents can silently damage the foundation of your property due to excessive moisture buildup. These dark and damp crawl spaces create the ideal conditions for mildew, mold, and bacterial growth. They also attract pests that start living in the nooks and crannies of your open crawl space. 
Without any intervention, these problems can spread throughout the entire house. It may lead to foundation damage, structural damage, HVAC issues, and other factors. Each of these consequences can be expensive and unsafe for families. 
Most homeowners remain unaware of the situation. That’s until they notice visible signs of structural damage or escalation of health issues. Luckily, we know how to turn things around. 
Complete Basement Systems specializes in offering practical and personalized crawl space repair services in Colorado Springs and Denver, CO. We use our expertise to identify the cause when we visit for a home inspection. 

Damage Caused by Open Crawl Space Vents

Many homeowners consider open crawl space vents just another fixture of the house. They think these vents are there for better airflow and humidity control. 
This misconception leads to a false sense of security. In reality, open vents are wreaking havoc inside your home. They often lead to costly maintenance bills, health issues, and other problems. The good news is, you can stop these problems before they develop, or stop the existing damage they’re causing before it escalates. You just need to look for the reasons why these open vents are harming your home. 
This usually comes down to environmental factors. 
Moisture Buildup and Air 
Despite popular belief, crawl spaces do not require ventilation. You should prevent outside air, water, and pests from interacting with your crawl space so it can remain dry and pristine. Sadly, open vents make this impossible. They function as easy access points for the elements. The most damaging will be humid air and moisture that gathers during and after storms. 
These unfavorable conditions will help grow mold and bacteria in your crawl space. However, as the problem escalates, it’ll also affect your HVAC unit. It will have to work overtime as humidity rises throughout your home and temperatures fluctuate. 
Worse yet, this outside air will pass through the unfinished crawl space and into your home’s ventilation system. At least 50% of the air you breathe becomes contaminated because of a musty crawl space. 
Water Intrusion 
The occasional rain in Colorado will lead to serious maintenance issues with open crawl vents. Rainwater can enter the crawl space through the entryways and collect there for prolonged periods of time. Excessive accumulation might lead to a flooded crawl space. 
The presence of water will also affect the HVAC system. That’s because damp air requires extra energy to heat or cool, depending on the weather. In turn, this means higher energy bills. 
Additionally, plumbing leaks, structural damages caused by open vents, and settlement might also maximize the chances of water getting in where it doesn’t belong. 

condensation in the crawl space

The Rise in Humidity Levels 
Relative humidity levels can be a leading concern for homeowners. Open vents lead to continuous interaction between hot and cold air. Because of this, the air collision causes the hot air to rise and condense. These factors can lead to the stack effect building up in your home, causing more damage as it does. 
Worse yet, if these conditions remain the same for a long time, then mold and bacteria will flourish. Wood rot, mildew, and fungi will have everything they need to spread: a damp and dark crawl space. This can spread throughout your home’s structural supports, flooring, walls, and up into the rest of your property. 
Without intervention, it could trigger respiratory problems and allergic reactions. The infestation can make your house inhabitable. That’s why keeping the air inside crawl spaces healthy must become a priority for homeowners. 
Pest Infestations 
Rodents and pests consider open vents to be ideal entry points into a safe hideout. Crawl spaces work as a shelter during harsh weather conditions. They also let them access the rest of the home with ease, getting into food storage, cardboard boxes, and clothing. 
Don’t think your crawl space is immune because it’s clean. All it takes is dampness and darkness. If your crawl space has a dirt floor or is unencapsulated, this becomes worse. Possible intruders include: 

  • Rodents and mice 
  • Gnats and flies 
  • Cockroaches 
  • Snakes 

Most of these pests are small enough to pass through grated vents. That’s why closing the crawl space becomes a practical option to limit pest infestation. 

Telltale Signs of Unhealthy Crawl Spaces

How do you know something’s wrong with your crawl space? Everything from excessive moisture buildup to humidity to pests will leave traces within the house. You have to learn how to detect the problem before things get out of hand. 

Keep an eye out for the following signs of crawl space issues: 

crawl space mold and wood rot
  • Structural damage (uneven or sagging floors, cracks, damp spots) 
  • Musty and foul odor 
  • Scratching noises and chewed cables 
  • Higher utility bills caused by damaged HVAC systems 
  • Wood rot or dry rot 
  • Water seepage and flooding in the crawl space 
  • Dirt and debris 

Call in a professional when you notice one (or more) of these issues. They can examine the problem and help you narrow down exactly how your open crawl space vents are affecting your home. With their insight, you can pick solutions that will bring this problem to a stop. 

Open Crawl Space Vents


Many homes in Colorado come with crawl space vents. If they’re that bad, you’d expect the original contractors to omit them from the blueprint, right? Their presence makes you wonder why it’s still common in households, even newly built ones. Here are the primary reasons why homes have crawl space vents: 
Old Traditions & Misconceptions 
A decade or so ago, homeowners considered crawl space vents an essential feature. They were designed to keep your space well ventilated, dry, and mold-free. Supposedly, it would also prevent humidity from accumulating inside the house by letting natural air floor circulate throughout your crawl space. 
Over time, homeowners have realized that this is untrue. Crawl space vents that are permanently open lead to drastic problems in the home’s maintenance. They expose your home to environmental conditions that should be kept limited, such as unregulated hot or cold air, water, moisture, and mold spores. Additionally, open vents leave a clear entryway for pests and other critters. Due to this, crawl space vents are gradually vanishing from remodeling and construction plans. 
The Legal Building Codes 
Many building codes include crawl space vents as a mandatory fixture for buildings. Its legal value overpowers any known disadvantages of building the vents to be permanently open. Years of industry experience have taught us otherwise. Yet builders can’t change the legislation. That’s why construction crews may stick to the lawful, old-school technique instead of updating their plans. 
Moreover, crawl spaces without vents take more time and care to develop. That’s why contractors install the vents instead of removing them. Homeowners can then alter and repair the layout according to their preferences afterward. With the help of a local professional, you can help make up for that earlier mistake. 

Vent covers for your crawl space will be an effective solution, but not if they don’t seal the vents full time. That’s because crawl space vents will continue causing problems whenever you open them for ventilation. It happens more often than not in the summer. Instead, homeowners should consult with a professional to have the vents properly sealed. If you try to simply block up the vents yourself, there will be problems. 
A Temporary Fix 
Homeowners consider crawl space vent covers as an affordable solution to all associated problems. Taking the DIY route seems counterintuitive because it does not undo the pre-existing damage. That means you will still need crawl space repairs to resolve structural and environmental problems caused by the open vents. 
More importantly, homemade installations are a short-term fix. They might protect your crawl space for a few weeks or months. There are, however, other factors involved that do not get addressed with a makeshift cover. As a result, secondary crawl space issues might crop up. Most of these may require professional consultation. Escalated damages could increase maintenance costs, making covers an expensive investment. 
Professional Installation 
Crawl space specialists can detect underlying problems when they arrive for a home inspection. Their expertise can help you fix issues and potential threats. They also provide premium-quality covers that have higher durability and weather-resistance. If required, they can tailor the covers to your exact vents and make sure they absolutely seal the vent, instead of opening or shutting. These covers can offer you better temperature regulation and control. 
Those qualities will make the custom-built covers a more viable and worthwhile option than DIY hacks. Besides that, our cooperative professionals can align crawl space repairs with your budget goals and individual needs. That means you shall get a well-fitted cover at a cost-effective price. Plus, you don’t have to worry about installation or maintenance. These services are a part of the service package. 

On the surface, having the option to open and close crawl space vents sounds doable. Even though these types of designs are better than open vents, they are still harmful. Let’s consider the pros and cons of this solution. 
The Advantages 
These vents are easy to close and open. Flexibility and control are the main advantages of this type of vent. For example, you can shut the vent whenever it’s raining or snowing in your area. When you do this, you stop floodwater from entering the crawl space and causing seepage or mold infestations. These benefits do not apply to open crawl space vents. 
The Disadvantages 
However, you might forget to close the vent. It’s an honest mistake that happens because you got busy or interrupted after you opened the crawl space vent. This possibility can become a constant fear for homeowners who prefer to keep crawl spaces enclosed. If you are not careful, the vent can remain open for a prolonged period. That leaves enough room for pests to get in and out of the house in your absence. 
Moreover, open crawl space vent problems go beyond pests and floodwater. Leaving the vents open for too long will cause the humidity and temperatures of your crawl space to fluctuate, even if it’s well encapsulated. It doesn’t take much for mold or fungal spores to spread into your crawl space, even if the vents are only open for a few hours or minutes.

The Solution: How to Maintain Healthy Crawl Spaces? 

Complete Basement Systems assists homeowners by offering crawl space repair services in the Colorado Springs and Denver areas. We also find alternative solutions for maintaining healthy crawl spaces. 
Most Colorado residents consider ventilation a necessity for healthy crawl spaces. After all, open vents let the air flow freely, helping bad air to exit the house. Unfortunately, there are some negative consequences too. That’s why sealing crawl spaces will become an ideal resolution for open vent problems. 
Our experts specialize in various crawl repair services. These include everything from complete crawl space encapsulation to minor upgrades. We provide vapor barriers, energy-efficient dehumidifiers, drainage solutions, and more. Let’s explore your options. 

Crawl Space Insulation 
Insulation prevents external temperatures from disrupting your home environment, allowing you to better maintain a healthy and consistent temperature inside the house. Without proper insulation, your open crawl space will let outside air and moisture into your property. Heat gets transmitted across the house through floorboards and other structural aspects. 
The fluctuating temperature can force your HVAC system to work in overdrive. In turn, it results in higher electricity bills and maintenance costs. Crawl space insulation services are part of the overall repair service. Its seals open vents and insulates the whole area. 

Insulation panel installed in crawl space

Benefits include: 

  • Reduces cold spots and drafts 
  • Optimal temperature regulation 
  • Prevents external air from coming inside 
  • Supports the energy-efficiency of modern homes 
  • Improves air quality 

In short, it plays a significant role in maintaining healthy and secure crawl space conditions. 

Crawl Space Vapor Barrier 
Vapor barriers are an advanced form of crawl space encapsulation. They are designed to seal crawl space walls and floors. 
These custom-made liners don’t let moisture and humidity pass through the open vents. The barriers ensure the area remains dry. The quick and simple installation process makes it a go-to solution for many busy homeowners. The barrier creates an airtight environment to prevent the growth of mold infestation and rot. Additionally, it’s important to have airtight vent covers placed over the vents to completely seal them off and prevent any air and water, and decrease pests’ interest in the space. 
These newly stable and dry conditions allow you to save on utility bills. Other advantages of these specialized liners include: 

  • High durability 
  • Rip-resistance 
  • Tailored design 
  • Professional installation service 

These features make them a worthwhile investment against common crawl space problems. 

Crawl Space Drainage System 
Crawl space drains are clog-free drainage systems. They reduce water collection and maintain dryness during humid conditions within your crawl space. They feature holes that collect water from walls and flooring and then directs it to a sump pump system
The comprehensive drainage system can not only remove any water that builds up but also prevent flooding or limit the amount of damage it does to your property. Whether you have a large or small crawl space, this can be an effective solution. 
The drainage system covers more ground and saves you from potential risks. The perks of these drainage systems include: 

important crawl space waterproofing measures
  • Reduced high humidity levels 
  • Maintaining your home’s energy efficiency 
  • Keeping crawl spaces clean, clear, and dry. 
  • No clogs or major water problems 
  • Your wooden floorboards and ceilings remain safe. 

Energy-Efficient Dehumidifier 
If you’re having issues with humidity in the crawl space because of your open vents, an energy-efficient dehumidifier can help once the vents have been sealed and the crawl space has been encapsulated and waterproofed. The ultra-powerful device has a compact structure that fits into narrow spaces. These machines operate on low-energy to ensure that you don’t have to pay higher electricity bills after installation. 
The high-powered blower keeps damp spots dry to prevent mold infestation. Additionally, our specialized product comes with a humidity sensor. The device regulates humidity levels in the crawl space without assistance. It even automatically drains the moisture. These specifications make it the ultimate press and set solution for crawl space repairs. 
Benefits include: 

crawl space dehumidifier installation prevent mold and rotten foundation
Dehumidifier Installation
  • No moldy walls or floors 
  • Inhibits bacterial and fungi growth 
  • Healthier and cleaner air inside crawl spaces 
  • Reduction of structural damage 

Any combination of these crawl space repair services can help limit challenges faced by homeowners in Colorado. After a free inspection, our team can help close up your open vents, repair any damage left behind, and safeguard your home’s crawl space against future damage. 

What Happens in the Free Crawl Space Inspection?

If you’re dealing with the problems that open crawl space vents bring, it’s recommended that you seek out the help of a professional. You can schedule a visit with our crawl space specialists. They will use the information you share and what they see onsite as a blueprint. They can then recommend the ideal solutions for your exact situation. 
Onsite evaluation allows our team to: 

  • Identify the primary cause of your crawl space problem. 
  • Detect hidden structural damage and environmental issues. 
  • Understand the logistics of a particular project. 
  • Share unique insights on how to solve these problems. 
  • Create a tentative timeline to start repairs. 
  • Discuss the budget before breaking ground. 

Once you give us the thumbs-up, we get down to work. Our dedicated team ensures that you receive real-time updates on the progress. We also ensure that our flexible solutions will align with your budget and your long-term goals. These include providing customized crawl space repair services to meet individual needs. We’re ready to serve you in the Denver and Colorado Springs areas. 

Let our crawl space experts help you

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Schedule free estimate
Let our crawl space experts help you

Get a Free Crawl Space Inspection from Your Local Expert 

Are open crawl space vents making your home unsafe? Call a specialist to fix the issue before the situation escalates. Our dedicated team of licensed contractors can examine the site, develop a personalized plan, and talk you through what comes next. 

With their input, you can eliminate the chance of wood rot, cold drafts, mold, and increased utility costs. Complete Basement Systems can use expertise and due diligence to help keep your crawl space dry, secure, and safe. 

Our specialized tools and solutions give you the ultimate protection, and we offer unique insights into tackling various crawl space problems without breaking the bank. If you’re interested in properly protecting your crawl space and home, you can contact us to request a free estimate and a no-obligation repair quote