Skip to Main Content
Nasty Basement with falling insulation and mold

Musty Smell In Basement

Basements aren’t always pleasant, but a musty smell coming from this area of your home is a sign that you have problems with dampness and mold.

Schedule Free Inspection
Nasty Basement with falling insulation and mold

If you are trying to make your basement into a viable living space for your family, or you just want to keep it in generally good condition, a musty smell can be worrying. When that smell begins to spread to the rest of your home, it becomes downright annoying. Air fresheners and candles will help, but they can only do so much. Plus, the smell isn’t the problem you should be worried about because it is most likely just a symptom of a much deeper issue. We’re talking about dampness, of course, and all the problems it can bring.

What Causes a Musty Smell in a Basement? 

To put it simply, the main or root cause of a musty smell in your basement is dampness, unless you have something down there that is rotting or holding a bad odor, that is. Of course, life is not quite that simple; your musty basement smell may be caused by moisture, but there are many other factors to consider. 

These are the most common factors that come together to make a basement smell musty or unpleasant: 


Once moisture gets into your basement, whether it seeps or leaks in, there is trouble ahead. Dampness can cause a huge number of issues that are damaging to your home and health, and the most commonly noticed result of this damage is a bad smell. It will also raise the humidity within your home, however, and this can cause a rise in your energy bills. 

Mold and Mildew  

When dampness meets organic material, mold and mildew are sure to form. Mold, in particular, can smell very bad, and while it is more often a symptom of damage to the wooden structures of your home than the cause, it can be bad for your health. Black mold, for example, can cause breathing troubles, migraines, and extreme fatigue when inhaled regularly. 


Once dampness gets into wood and cloth, it’s only a matter of time before rot sets in. If you don’t dry out damp materials quickly enough, they will become soft and begin to degrade. This will add to the musty smell in your basement, but also undermine the structural integrity of your home and attract unwanted guests. 

Pest Problems 

Pests like mold mites, termites, cockroaches, and rodents love dark, damp, humid spaces. Once an infestation takes root, it will add to the unpleasant smell of mold and dampness, but more worryingly, these pests can also damage your home. 

Musty Smell in Basement


The most common causes of a musty basement smell are mold and dampness. The root cause of these issues, however, can vary. 

  • Dampness 

Dampness may be caused by leaks in your home’s plumbing system or appliances or cracks in your foundation. It can be hard to know just what the causes of dampness are until a full inspection has been completed. With that said, some causes are far more likely to be the root cause of dampness in a home. 

First and foremost, foundation and structural damage commonly contribute to persistent problems with dampness. This is because of how cracks in a wall or floor act as direct channels for water in the soil around your basement. However water gets into your property, it will begin to stagnate and cause a musty smell. 

  • Pests and Mold 

Once dampness makes its way into your basement, it will raise the humidity levels in your home and lead to mold and mildew formation in many cases. This can have a huge effect on the smell in your basement as the water stagnates, but mold formation is a far more pressing concern when it comes to bad odors in a home. Mold loves dark, humid environments and creates a sweet, musty smell. 

Depending on the species of mold that forms in your home you may also experience skin irritation and respiratory problems, or even see an increase in the number of pests on your property. This, in turn, will add to the bad smells in your property, as well as a general decrease in overall hygiene levels. Furthermore, there is a high chance that the mold, and the musty smell, will spread over time.

If you want to get rid of the foul smell in your basement, you need to dry it out and remove all mold deposits. This may sound easy, but it can be quite difficult and dangerous. Some forms of mold are irritating to the skin and can damage your respiratory system. To get rid of the smell and mold for good, you need to prevent dampness from getting into your basement and dry it out. This can be complicated and time-consuming, so it’s best to contact a professional for advice and support. The best solutions for odor removal are: 

  • Damage Repair 

Identifying and repairing the damage which is allowing dampness into your home is all-important if you want to eliminate bad odors. Have a professional assess your home and deal with any damage that may be contributing to the humidity levels in your home. After all, it won’t matter what you do to remove the smell if your basement stays damp; it will only recur. Installing waterproofing measures into your property, too, will help to manage humidity levels. These will be especially important if you are unable to fully cut off all sources of water on your property. A sump pump and vapor barrier will go a long way towards keeping the environment in your basement comfortable. 

  • Dehumidification 

Once the main cause of water and dampness are resolved, it is important to dehumidify your basement fully to remove bad odors and prevent mold recurrence. Humidity in the air is a huge factor in mold formation, after all, and mold is one of the biggest factors in the creation of strong, musty odors in a basement (or any space, for that matter). 

An energy-efficient dehumidifier will provide you with a consistently dry, comfortable environment that is non-conducive to mold formation. A professional can install one in an hour or so. This will prevent the musty smell from recurring in the future, of course, but it may not completely remove the musty smell that is already present. For that reason, you should look into ways to deodorize your property. 

  • A Deep Clean 

Once you have repaired all damage and the humidity in your home is under control, a deep clean is your best option for removing all remaining traces of mold, pest droppings, or rotted organic matter from your basement. This will help you to chase the last of the bad smells away and has the added bonus of leaving your basement sparklingly clean. 

Your biggest concern when undertaking a deep clean should be killing all the mold formations that are already in your basement. There are specialized cleaning products that are designed to remove mold, but a blend of bleach and water will do the trick just as well. Remember to wear gloves, however, as bleach can be hard on your hands. For more serious cases, be sure to contact a mold remediation professional.

Once you have removed the mold and dampness from your basement, waterproofing measures are the only way to truly prevent the issues from recurring. 

  • The Right Gear 

Installing a vapor barrier and an energy-efficient dehumidifier can make all the difference to your property. However, you should also make sure your sump pump is in working order and that you have sufficient drainage systems in your basement and yard to prevent dampness from making its way back into your home. 

If your property has not undergone waterproofing measures recently, or at all, it is best to call a professional to have your basement assessed for warning signs and weak spots. This will highlight any underlying issues that may need to be repaired, as well as provide you with a tailored list of suggested waterproofing measures for your home. 

  • Professional Waterproofing Saves You Money 

This may seem strange but spending money on professional waterproofing can save you money in the long run by reducing dampness and humidity. A professional will be able to tell you what you need to make your property safe and healthy once more, and they will provide you with the best possible products and services. This prevents dampness-related damage but can also lower your energy bills as a result of this low humidity. 

Professionals will be able to get their hands on products that are not readily available to the general public. These specialist products are often more effective and durable than their commercial counterparts. This means that you only pay for what you need, and get a high-quality, durable solution that protects your home and your bottom line!

Why Is a Musty Basement Smell Something to Worry About? 

Aside from making your basement unpleasant to be in and causing damage to your home, a damp environment and musty smell are often symptoms of much more serious pre-existing and invisible damage. You see, unless you have a clear idea of where the dampness in your basement has come from, the most likely sources are: 

Internal Leaks 

If you notice standing water on your basement floor or near the walls – even a small amount – you could have an internal leak. An internal or plumbing leak will most often come from your pipes or an appliance such as your water heater. Thankfully, leaks like these are fairly noticeable and easy to fix. 

External Flooding 

Extreme rainfall or outdoor flooding can cause water to enter your home. This can, of course, be the result of very dramatic flooding, but most often it is caused by the inability of your current drainage systems to remove water from your basement and foundation. A clogged gutter or broken sump pump could be your worst nightmare in these situations. 

Cracks in Your Walls 

Most often caused by excess hydrostatic pressure, cracks in your basement walls offer water the perfect gateway into your home. They can also be the first signs of wall displacement, leaning, or bowing, so it pays to get them checked out as soon as you notice them. 

Foundation Settlement 

One of the most common causes of dampness is water seeping into your basement from below. Repeated droughts and floods can cause cracks to open up in the soil underneath your home. As the soil expands and shrinks, your foundation is put under severe stress and can crack as it settles. These cracks allow water to seep into your home. As you can see, that musty smell in your basement is so much more than an annoying disturbance to the peaceful and pleasant atmosphere you have created. It is a serious red flag that warrants your immediate attention. 

Diagnosing and Fixing Your Musty Basement Smell 

The problem with trying to get rid of mold and dampness yourself is that it’s hard to effectively diagnose the issue without a full inspection of your basement. The only way to permanently fix the issue and remove the smell is to address the source, or sources, of moisture. If you fail to do this or fix only some of the issues, you will face recurrence regularly. Worse still, you could fail to notice a tertiary problem and end up facing more serious issues in the future because it has been allowed to escalate unchecked and unobserved. 

This is why we recommend that you hire a foundation and basement specialist to assess your home. A full inspection will not only uncover the main causes of dampness in your basement but will also highlight any tertiary issues that have been caused by prolonged or repeated dampness in your home. By doing so, they will be able to address all the causes of dampness, mold, and bad odors in your basement at the same time. As a result, they will be able to leave your home feeling and smelling fresher than it has in a long time. So, professional help is well worth it in the long run. 

Foundation Recovery Systems has been helping Missouri homeowners to prevent black mold and banish dampness and musty basement smells for more than 20 years. We know what your home needs, and we know how to undertake repairs and waterproofing measures with minimal cost and disruption within your home. We also know that the quality of our work and the passion of our team members speak volumes. This is why we offer free inspection appointments and provide a same-day written quote without any booking obligations.

FRS service area

Our Service Areas

Central Illinois Location

2064 N Woodford St.
Decatur, IL 62526

Des Moines Location

2401 SE Creekview Dr.
Ankeny, IA 50021
(515) 373-8491

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
3020 N. Martin Ave.
Springfield, MO 65803
(417) 612-8286
St. Louis Location

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