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Crawl Space Mold

Mold is common in homes that have exposed or unsealed crawl spaces. Learning to recognize the problem signs is key to maintaining good health.

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Some homeowners think that crawl space mold is a relatively small issue in the grand scheme of things. After all, if you have structural damage, flooding, and other more pressing issues at work in your home, mold pales in comparison. Nonetheless, mold formation in your home is a serious issue that can impact your home and your health in many unexpected ways. 

Thankfully, mold is relatively easy to deal with on its own. A mold removal professional can remove formations and a crawl space repair contractor can prevent recurrence quickly and efficiently. Of course, it would be far preferable to prevent mold from forming in the first place.  

basement mold

How Mold Gets In 

Mold requires three basic things to take root: moisture, food, and the presence of spores. If one of these things is missing, mold formation becomes highly unlikely. Unfortunately, most places have native mold species and spores present to some degree. This means that all mold needs to find in a property is a suitable food source—some form of organic material and an appropriate level of humidity. 

Exposed Wood and Textiles   

When mold forms in a crawl space, it is most likely to set up shop in exposed wooden beams or joists, exposed insulation, or any organic materials/belongings you have stored there. 

Internal Leaks 

If your crawl space has been waterproofed and sealed at some point, it should have no issues with mold. An internal leak from your plumbing system or appliances can change all of this, however, and leave you with a serious mold problem. 

Structural Damage 

If you have damage to your property—for example, cracks in your crawl space walls or you are in need of foundation repair—you are far more likely to have issues with dampness in your home. With dampness, of course, comes mold. 

Once mold gets into your home, it can take some time to form and spread. Learning to recognize problem signs and red flags is all-important when it comes to nipping a mold infestation in the bud. 

Crawl Space Mold: The Problem Signs 

The problem with mold is that, rather like pest infestations, by the time you can see visible evidence, it is generally already well entrenched in your home. This is due in no small part to the fact that bleach and certain other cleaning products are known to kill spores. As such, mold is more likely to take root in areas that are not frequently used or cleaned. 

There are some exceptions, of course; if you have a particularly humid kitchen or bathroom that is poorly ventilated, you are very likely to find it on the ceilings in these areas. Assuming the mold formations are not visible, however, there are some warning signs you should be aware of. 

Recognizing these problem signs early will help you to find and address mold before it gets out of hand. 

High Indoor Humidity 

A high level of indoor humidity is a serious red flag when it comes to mold and mildew (as well as a host of other issues). There are a number of ways to test your home’s interior humidity but being on the lookout for condensation is a simple way to monitor the situation. A certain level of humidity is normal, and there will be times when you see condensation that is not concerning; for example, humidity forming on your kitchen windows when you cook. 

However, finding condensation on your walls is a strong sign that relative humidity in your home has reached unhealthy levels. This is especially the case if the walls in question are in rooms that are not used for washing or cooking. If you find condensation like this, you should call an expert. If you do not already have mold, it is sure to form in these conditions. 

Musty Odors  

A musty smell in your property is generally indicative of problems with dampness, but there are also certain species of mold that can cause a musty, sweet, or slightly putrid odor. It does depend on the species of mold, of course, and the smell caused by dampness is likely to be present at the same time. It can be hard to tell what the precise cause of the scent is if you have no experience. 

As such, we recommend that you report any lingering bad odors in your home if you can find no obvious cause for the scent. A professional will be able to investigate your home and isolate the precise cause of the bad smell before suggesting a solution that is tailored to your needs. 

Wood Rot 

Dampness, wood rot, and mold formation go hand in hand (pest infestation is often a connected issue, too). Rotting wood changes in appearance and texture and will lose its structural integrity. This can look different depending on the item in question. Wooden floorboards, for example, are likely to warp and become bouncy when they rot, whereas furniture may seem fine until it starts to fall apart. 

If you see visible signs of wood rot or degradation in your home, it is likely that mold is either a contributing factor to the rot, or at the very least, present and feeding on the organic material. As such, you should contact a professional as quickly as possible when you see it in your home. 

Sagging Floors 

Sagging floors are connected to wood root and dampness, of course, but they constitute a separate warning sign for a few reasons. First and foremost, when an otherwise healthy floor starts to sag, it is a sign that there is a problem in that floor’s support system. When you have a crawl space and the floor above it begins to sag, the issue is most likely with either the joists or beams in your crawl space or with your property’s foundation. 

Assuming you don’t have foundation problems like settlement or subsidence, the most likely cause of damage to your supports and joists is dampness and, as a result, rot. Where there is rot, mold is likely to form. As such, sagging floors are a warning sign of many issues from dampness and foundation damage to mold formation. 

If you see these problem signs in your home, it is likely that you have dampness and mold at work in your home somewhere. It is important that you investigate thoroughly when you find such issues, as it is unlikely that mold will form in isolation. Once you have identified the underlying issues, it is imperative that you deal with them quickly. 

Crawl Space Mold


Mold is a surprisingly robust substance that can thrive in many different environments, temperatures, and areas. There are only three requirements for mold formation: moisture, spores, and organic material. Most crawl spaces have organic materials (like exposed wood) and every area has prevalent mold species. 

Internal Leaks  

Some of the most common causes of dampness and humidity in Colorado Springs and Denver properties are internal leaks from a home’s plumbing system or attached appliances. In a property that has an unsealed crawl space, for example, it is fairly common for pipes to freeze during the harsh Colorado winters. This can cause them to burst and flood the crawl space. 

While the flooding itself can be drained easily, the dampness that a serious flood leaves behind, however, can be lingering. This is because of the way it will saturate insulation and seep into any exposed wooden supports and joists it touches. This saturation will release moisture into the air and cause the relative humidity to rise. If this persists over time, mold is sure to form (along with a large selection of other issues like mildew, pest infestation, and rot). 

Structural Damage 

Of course, moisture can also get into your home via points of structural weakness and damage. Cracks in your crawl space walls, for example, will let water seep into your home. This kind of seepage will be most pronounced during the wettest months of the year, storms, and of course the spring thaw. Another gateway for moisture is foundational damage. 

Damage like foundation settlement or subsidence is notorious for causing persistent dampness and humidity in a property’s crawl space. When cracks appear in your foundation, they essentially act as channels for groundwater to make its way up into your property. This will, of course, be more severe during wet seasons. 

It can be tempting to think of mold as a harmless irritant, and this certainly may be true for certain species of mold, but others can be genuinely harmful to both your health and your home. This is why it is so important that you act quickly when you see signs of damage and mold formation in and around your property. 

Structural Damage  

Mold needs organic material to form and spread, in most cases. It won’t grow on surfaces like stainless steel or marble, but loves cloth, wood, drywall, and will even form on some kinds of wallpaper. This is because it needs to feed on the organic material in order to keep itself alive as well as grow and spread. This has an impact on whatever the mold is feeding on, of course. 

As mold eats away at the organic material that it has formed on, it weakens the material. As such, if mold forms on a damp support joist, it will eat away at that joist, making it weaker and weaker. This can lead to the joist starting to buckle and crack, leaving the floor above to sag due to a lack of support. As you might imagine, this can have serious implications. 

Health Concerns 

As well as being unhealthy for your home, mold creates an unhealthy, unhygienic environment that can cause a number of health issues. First and foremost, certain species of mold, like black mold, are directly harmful. They can cause skin irritation and infections, respiratory issues, and even persistent headaches and migraines. 

Other species of mold may exacerbate pre-existing conditions like eczema or asthma. This can be incredibly serious for people who are already in poor health. Finally, most species of mold will be attractive to some kinds of pest. Homes with a serious mold presence are more likely to deal with spider, cockroach, and even rodent infestation. 

Getting rid of mold is not as simple as scrubbing away the visible formations; you also need to find a way to prevent it from reforming at a later date. In this endeavor, it is best to avoid the DIY methods you will find on many blogs. While they may claim to be effective, they do not take underlying issues into consideration and could cost you more money and time. 

Manage Humidity 

If you want to control mold and prevent it from spreading throughout your home while you find the best way to deal with it, managing the level of humidity in your home is all-important. This is also key in preventing mold from forming again after you have removed it from your home. Of course, keeping an ideal level of relative humidity in your home is a good idea in general. 

If you have not waterproofed your crawl space already, it is something you should consider. Sealing and waterproofing your property’s crawl space is one of the best things that you can do to protect your home from dampness and all the trouble that it can cause. This is not something you should do alone, however; professional help is essential to getting the right result. 

Call a Professional 

Getting rid of mold is a specialist task, and as such, you should contact a mold removal professional as soon as you notice it in your home. First and foremost, the chemicals and processes required to completely remove the mold in your home can be dangerous if you don’t know how to use them properly. Secondly, depending on the type of mold you have, follow-up work may be required. 

After you have called in a professional who specializes in this task to remove the mold in your crawl space, you’ll then need to reach out to crawl space repair professionals. Those experts will assess your home and make a decision as to how they can help you to protect it from recurring formations and issues. This means they will be able to create a tailored waterproofing plan for your home as well. By allowing an expert to take this work on you will save money in the long run and ensure a quality result that is long lasting and effective. 

Dealing with Mold: Is DIY a Viable Solution? 

There are plenty of blogs and websites dedicated to DIY solutions for issues like mold, but we recommend that you do not attempt to deal with these issues alone. First and foremost, certain species of mold can be dangerous to your health and wellbeing, and there is really no way to identify them without proper testing. Exposing yourself to these kinds of mold and their spores could cause many problems, including, but not limited to: 

  • Persistent headaches 
  • Respiratory problems 
  • Skin irritation 
  • Infections 

In fact, the sudden onset of issues like these, or an exacerbation of pre-existing conditions, is another problem sign to look out for. Of course, most people don’t immediately think of mold when their health deteriorates (which is why other red flags are so key). These are other reasons to avoid DIY solutions: 

The Dangers: Chemicals and Costs   

While there are many homebrew mold remover recipes online, many of the most dangerous species of mold are hardy and tenacious. This is why professionals use specialist chemical mixes to kill the formation and spores before drying out the surface to prevent recurrence. This is an intensive task that has many dangers because of the often corrosive nature of the chemicals. 

If you try to go it alone, you could not only end up hurting yourself, but you could fail to remove all the mold and spores. As such, you will find that the relative cost of mold removal rises in cases where a DIY repair is attempted first. 

There is also the issue of underlying problems and structural damage to consider. Even if you manage to remove mold fully, persistent dampness will lead to a recurrence at one point or another. You have to ensure that you deal with all underlying causes to get an effective fix; this is where professionals really shine. 

Why You Should Call an Expert 

Unless you are certain that the mold has been caused by a single source of dampness, it is very likely that a range of repairs and waterproofing measures will be needed to secure your home. These tasks are not suitable for amateurs, especially if the repairs are structural in nature. This is partly because of the specialist skills required to undertake them, but also because of the heavy tools that can be required. 

An expert will be able to diagnose and effectively repair any issues and underlying causes that come to light. This will ensure that you get a permanent solution the first time the issue is handled, but also that the overall cost is lower than it would be if you had to deal with each cause as the mold recurred and required further investigation. 

In short, professional help is safer, quicker, more effective, and generally provides good value for money. So, while it can seem daunting to hire an expert, we urge you to avoid do-it-yourself options and let someone in the know take care of your family and your property.  

Let Complete Basement Systems Help You Prevent Crawl Space Mold 

The team Complete Basement Systems has been the resident crawl space and basement specialists for Denver and Colorado Springs, CO, for years. Our team is made up of dedicated, experienced, and knowledgeable staff that is determined to help each and every customer get the very best, tailor-made results. 

If you are worried that you may have mold, dampness, or damage at work in your crawl space, we are here to help. All you have to do is arrange a free inspection appointment to get the process started. All our inspectors are highly trained and personable. They will arrange a date that suits you and conduct a full analysis of your crawl space to identify the extent and nature of the issues within your home. Once they know what they are dealing with, they will run you through their suggested solutions and provide you with a same-day written estimate for the work. 

All of this comes with absolutely no obligation to book repairs through us. We believe that our work and reputation speak for themselves and will never pressure you to make a quick decision. You can take all the time you need to shop around, but if the situation deteriorates quickly, please feel free to call our team. Your health and safety is our main concern. 

Serving Greater Denver area, Colorado Springs, Eastern Colorado, and parts of Nebraska and Wyoming

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Palmer Lake, CO 80133

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Denver, CO 80216