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Musty Odors

A musty smell in your home, even at a low level, can point to many different problems within your property as a whole. Learning to read the problem signs is key.

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Do you have a musty smell in your basement? Does it seem to be spreading through every part of your home, getting stronger no matter what you do to get rid of it? If so, it’s time to call in a professional to investigate it properly. There are many issues that could cause a musty and unpleasant smell in your home.  

From mold and mildew to wood rot and pest infestation, each of the issues that can cause a bad smell will also have other effects on your home. Learning to determine subtle differences in the smell in your home, and knowing when to start an investigation, is incredibly important to the health and well-being of your home and your family. 

What Causes Musty Odors? 

Unfinished crawl space with water damage

The precise cause of bad odors in any property can be linked to a number of issues, and in fact may be caused by a mixture of issues. However, the issues most likely to cause musty odors in particular are those that are connected to dampness, fungal growth, or pest incursion. 

Dampness and Humidity 

Dampness and humidity are some of the most common factors found in homes that are dealing with a musty smell. For example, the smell of stagnant water can be surprisingly strong and will have a musty and unpleasant edge. If this is the case, you are likely to find pools of water in your basement or crawl space. 

Even if there are no visible pools of water, high levels of relative humidity can also cause a generally musty smell by contributing to dampness and creating condensation. These conditions are generally more conducive to mold, mildew, and fungal growth and formations, especially in spaces with a lot of organic material. 

Mold and Mildew 

Mold and mildew are one of the most common causes of a strong, musty odor in a property’s crawl space. The smell may spread through your property as a whole quite quickly, meaning that a musty smell in your bedroom could still be coming from mold in your crawl space. This has a lot to do with the way in which mold spores become airborne. 

You will recognize mold formations and growth by the rounded, spreading patches of discoloration that they can cause. Mold can be grey, brown, pink-ish, green-ish, or black in color (depending on the species) and may also take a slightly fuzzy or furry texture as well as a musty smell. 


A persistently damp and humid environment can also have an impact on organic surfaces within your home. Exposed wood, cardboard boxes, and textiles, can all be impacted by rot if they are subject to dampness and humidity on a consistent basis. Rot in organic materials is not only unpleasant, but unhealthy. 

Wet rot affects different surfaces and materials differently. Wood will become soft, slightly slimy, and will often have a white-ish sheen. Wet rot can produce a strong, musty, or stagnant smell that is quite similar to that produced by mold. 

Pest Infestation 

Pest infestations are also notorious for producing a bad smell in a property. This is not the only negative side effect associated with pest infestation. Depending on the pest in question, infestations can undermine the structural integrity of your flooring and even impact your health and well-being. 

The most common pest infestations in homes in and around Mobile, Alabama, are cockroach, rodent, and termite infestations. Each of these has its own set of problem signs and potential issues, as well as a distinct odor. Termites are the most damaging to your property’s structure but also the least likely to produce a strong odor. 

By contrast, a rodent infestation can cause a strong smell of urine to pervade a property. Larger rodents like rats can also cause damage to pipes and wires. Finally, cockroach infestations can cause a strong, vinegary smell and lead to serious illness if you or anyone in your home has a compromised immune system. 

In many cases, the source of a musty smell will be a combination of these issues. This may not seem like an immediate issue, but we recommend that you do investigate as these kinds of smells can represent a real danger to your home or health. 

Why Worry About a Musty Smell? 

Keeping on top of your property’s condition can be tough. There are so many little things that can go wrong and so many places where the signs of damage can percolate, hidden from view. With this in mind, you can be forgiven for thinking that a musty smell in your basement is the least of your worries, but there are a few reasons you should consider this odor a serious problem sign. 

Bad Odors Indicate Damage 

Dampness is one of the key factors in the creation of a musty or stagnant odor in a property. In essence, this kind of smell can be the first and most obvious sign of damage to your property’s structure or plumbing system, especially if the leak is very small or out of sight. 

By investigating fully as soon as you notice this, you could catch the problem before it snowballs and causes avoidable damage to the rest of your home. 

Musty Odors Indicate Unhygienic Conditions 

A bad, musty smell is a strong sign that the environment in a space is unhygienic. That’s not to say you do not clean, but rather that there is something undermining your cleaning routine, whether it be mold and dampness or an active pest infestation. Whatever the cause of this dirt and smell, it can escalate and ultimately affect your health. 

Cockroach infestation and mold formations are particularly worrisome, for slightly different reasons. Cockroaches are incredibly dirty creatures that leave bacteria and germs everywhere they go (and they get into everything). This can lead to infections in small wounds, skin irritation, and general illness if they come into contact with your food or eating utensils. 

Mold, by contrast, is generally benign with the exception of certain species. While most kinds of mold will cause general irritation to the skin after direct contact, some can be more actively harmful. Black mold, in particular, is very toxic when you breathe in the spores. Black mold can cause headaches and migraines, throat, ear, and nose infection, respiratory problems, dizziness, and even fainting. These effects will be more strongly felt by people who have underlying health conditions. 

Bad Smells Make Your Home Uncomfortable 

Above and beyond other issues, a musty or unpleasant smell in your home can make it a very uncomfortable and unpleasant environment to be in. Your home should be a place of comfort. While it may seem like a cosmetic issue, a bad smell stemming from mold, rot, or pest infestation is a fixable issue that when left ignored, only gets worse.  

Anything that impacts the environment and interior climate of your home will impact your comfort (and the comfort of your family). If you happen to be planning on selling or renting your property, this will have a far more tangible, financial impact. In fact, a bad odor could actually lower the price you can expect to get for your home (because it indicates that there is damage to the property). 

As you can see, it is important that you do not ignore musty odors in your home. There are just too many issues that could be hidden away in your home, quietly growing while the odor is the only noticeable red flag. as 

Problem Signs You Should be Aware  

While we always recommend that you investigate a musty odor in your home, especially when a deep clean and thorough airing of your home does not dampen or remove the smell, we understand that it can seem like a minor problem. We recommend that you look for these problem signs as they indicate the presence of structural damage, plumbing issues, or the presence of mold and pests: 


Cracks on walls and in your concrete floor or slab are a bad sign no matter where or when they appear on your property. Cracks in your home will only grow in size. When they appear in conjunction with a bad, musty odor, it is likely that the cracks have breached the full width of the wall or floor in question. This can allow water to seep into the property from outside and allow dampness, high humidity, and mold and mildew to affect your home. 

Stains and Discoloration 

Stains and discoloration can be indicative of many issues, but the most likely underlying issues are mold formation and leaks. Consistent water and dampness, either from a leaking pipe, window, or crack that is allowing water to seep through, will stain concrete surfaces over time, creating orange-ish or dark patches. Mold, by contrast, can cause discolored patches of many colors and will often take on a furry texture. 

Droppings/Shed Exoskeletons 

If you find animal droppings, chew marks, or shed insect exoskeletons around your home in conjunction with a bad odor, it is likely that you have an underlying pest infestation to deal with. The precise nature of the smell and the contextual signs of infestation will allow a professional to determine what pest is most likely to be at work in your home. 


Condensation occurs when high levels of relative humidity clash with sudden cooling in the air, or a cold surface in the area. This can cause damage and contribute to generally higher levels of humidity throughout a property, making condensation part of a vicious cycle that creates an ultimately unhealthy environment in your home. 

Pooling Water 

Pooling or standing water anywhere in your home is the single strongest sign that you have damage to your property’s plumbing system. This is especially the case if you can see a steady stream of water, or you have noticed irregular dripping in the area around the pool of water. If you see this, it is likely that dampness, or issues related to it, are to blame for the musty smell in your home. 

Each of these problem signs can be connected to a number of issues and, as such, should not be ignored when they present themselves. Acting quickly and calling a professional when you see these red flags in your home can save you a lot of time and money in the long run. 

Musty Odors


Tackling the musty smell in your home can take many different forms, depending on the cause of the smell and the underlying issues at work in your home. With the help of an expert, you can get to the bottom of the foul smell in your home, and eliminate the problem at the source.  

Cleaning and Airing 

If the musty smell in your home’s crawl space was being caused by a pest infestation, the buildup of debris, or fungal growth following flooding, a deep clean and thorough airing may remove the smell altogether. You should start this process by removing all of the visible debris from the area in which the smell is strongest. Check this debris for signs of mold, mildew, and rot to make sure that there are no deeper issues at work. 

Once the area is free from all debris, you should look for signs of an active infestation. These include sightings of the pest themselves, finding droppings, and seeing nest formations. In the case of termites, you will see damage to wooden surfaces and supports. If there are no signs of active infestation or mold formations, you should proceed with a thorough cleaning of the area (remember to wear a mask and gloves if you use bleach), then allow the space to air out before closing it off again. If the debris was the cause of your musty smell, it should go away after this. 

Structural Repairs and Dehumidification 

If the musty smell in your home continues after a deep and thorough clean, it is very likely that there is another issue at work. Mold formation as a result of persistent dampness, for example, or wood rot as a result of dampness can cause a bad smell to take root in a property quite easily. The source of this moisture can be structural damage or plumbing damage, but whatever the cause, it will need to be repaired to get rid of the smell. 

Cutting off the source of moisture is vital to creating the right conditions for climactic stabilization and the removal of the musty odors in your home. The nature of these repairs will depend on a number of factors, including the severity of the damage, the nature of the damage, and the presence of other issues and complications. Cutting off the main source of moisture won’t remove the smell and secondary issues that have been caused. 

Waterproofing and encapsulating your crawl space can be of great help when it comes to removing musty odors and preventing their recurrence. There are other benefits to waterproofing your property’s crawl space. 

What Waterproofing Does 

Waterproofing and encapsulation are common procedures in and around Birmingham, Alabama, which involve creating a contained, watertight space inside a property’s crawl space or basement to prevent water damage and lower humidity. It does this by taking a multi-step approach to exert climate control and stabilize the environment in a space. 

Generally speaking, crawl space waterproofing and encapsulation cover matters of ventilation, drainage, insulation, and seepage. This means covering or sealing crawl space vents and doors, installing better drainage solutions, insulating the walls, floors, and pipes, and installing a moisture barrier and dehumidifier. 

The Benefits of Waterproofing 

Choosing to waterproof your property’s crawl space has many potential benefits for your home, your health, and even your finances. As well as preventing moisture, dirt, pests, and airborne allergens from entering your crawl space, waterproofing and encapsulation will lower relative humidity in your home as a whole. 

Secondly, waterproofing your crawl space will stabilize the temperatures within the space (and the rest of your home) by increasing your home’s ability to retain the heat or cold created by your HVAC system. The reduction in humidity will also stabilize temperatures because arid air is easier to condition than humid air. The result of this is increased energy efficiency and lowered energy bills. Better still, it creates an environment that is healthier. 

No. You should not attempt to waterproof and encapsulate on your own. While DIY may seem tempting, there are many ways for it to go wrong.  

Underlying Issues Must Be Dealt With First 

One of the biggest issues with waterproofing is that you must deal with any underlying damage in order to get the best results. If you do not deal with underlying foundation damage, structural damage, plumbing leaks, or unsealed crawl space vents, you will simply cover up the damage. This can allow it to grow unchecked, or even lead to the dampness recurring in your crawl space. 

This can actually make the issue worse than it was before, because of the way in which a waterproofed and encapsulated crawl space will trap any moisture that does gather in it. By cutting off ventilation, any crawl space that does not have a dehumidifier will simply hold any moisture that gathers in it and allow it to percolate. This will magnify the issue. 

Professional Products Are Hard To Find 

The process of waterproofing may be relatively straightforward, but it does require specialist tools, skills, and products to get the best possible results. Many of these tools and products are hard to find in the average hardware store but are easy for professionals to get through supply stores. 

Likewise, the experience and training that professionals have means that they are most qualified to use these tools and products effectively. Even a slight mistake with something like a vapor barrier can cause a lot of damage, and in a cramped environment like a crawl space, it’s easy to have accidents. This means that while hiring a professional may seem more expensive, it can actually be more cost-effective in the long term.  

Call AFS for Basement and Foundation Repair 

If you have noticed a strong, musty, or foul odor in your home, our experts are here to help. AFS foundation & waterproofing specialists has been helping homeowners restore their homes to full health since 2000. We’re happy to serve Birmingham, Huntsville, and Mobile, Alabama, and Nashville, Chattanooga, and Knoxville, Tennessee. As a locally owned and operated business, we offer free inspection appointments 

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