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Musty Basement Smell

Nasty smells coming from your basement are not something you should ignore. They are often a telltale sign that something is wrong.

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Although a lot of basements smell bad, the truth is, they shouldn’t. If your basement is clean and dry, such smells should not be present. Therefore, take this smell as a sign of trouble. 

While the basement is surely not the nicest part of your Michigan home, it shouldn’t have a gross, stale odor. If your basement has been smelling musty lately, you should inspect it thoroughly. This is often a sign that something, somewhere has gone south. Addressing the source of the smell instead of ignoring it altogether can save you a lot of money down the road. 

So, what can cause those nasty, musty smells? How can you get rid of them? Is there a way to avoid having them in your basement? Let’s find out. 

Why Does My Basement Smell Musty? 

It is often not easy to figure out what is causing the bad smell. This is because a basement has a specific smell, the kind you won’t encounter anywhere else. But what causes it? Several things could be the source of a musty-smelling basement. Here are the most common culprits. 

Organic Material 

Some type of organic material may be making your basement smell bad. Your floor joists are made of wood, which is an organic material. In addition, many types of insulation contain such materials as well. If you do not properly maintain your basement, there may be a chance that your insulation is coming out of the walls and falling from the ceiling. While you can sweep up fallen insulation, you will never be able to remove all the organic materials from your basement. If wood is a part of your foundation, it will remain there forever. The good news is that organic material is just one part of the equation. It won’t smell bad on its own. It needs high relative humidity to turn your basement into a stinky place.  

High Relative Humidity 

The next thing on our list that could cause a musty smell in your basement is humidity. Relative humidity refers to how much vapor is in the air, compared to how much moisture that air can hold at that temperature. For example, if the air is at 50% humidity, that means it is saturated with 50% of the moisture it could potentially hold under the same conditions. 

Why is relative humidity important? Because if it goes to 100%, the air is as saturated as possible, and all that moisture needs to go someplace. It usually comes out as condensation on a cold surface such as a window or a water pipe. High relative humidity is dangerous because it creates an ideal environment for all kinds of germs and fungi. 



In most cases, mold is to blame for that musty smell homeowners hate. It needs organic material (which you have in your basement) and high humidity levels to thrive. When the relative humidity level goes above 60%, mold starts to spread all over your basement. However, be careful. Even if the rest of your basement has low humidity levels, mold can still form around condensation spots such as windows. 

Mold is often described as something you must not have in your home. While it is rarely toxic, it often causes allergic reactions and respiratory problems. If you have mold in your basement, you could end up with flu-like symptoms such as sneezing, runny or stuffy nose, cough, watery eyes, and itchy eyes, nose, and throat. Dealing with such health problems can be frustrating, especially if you do not know what is causing them. Having mold in your basement won’t kill you, but it can affect your quality of life. 

Therefore, if your basement has started to smell musty, ask your basement waterproofing specialist for help. 


If your basement is humid, wood and other organic materials will surely begin to rot and deteriorate. This process is usually very quick, so you should not ignore those nasty smells. Rotting items can smell incredibly bad, but that is not the worst part. If structural elements begin to rot, they could become unstable and compromise your home’s structural integrity. Thereby, if your basement has a pungent smell, look for signs of rot. 

Pest Infestation 

When pests move into your basement, they can not only damage everything on their way but turn your basement into a health hazard. A nasty smell is often a result of infestation, and the strength of the stench depends on its severity. If you only have a couple of mice down there, they won’t stink up the place. However, if they make nests and breed, soon you will notice a foul smell.  Believe it or not, mice, rats, or rodents for that matter won’t make your basement smell as bad as some other pests will. For example, the smelliest infestation is a cockroach infestation. These nasty bugs are dirty, they shed their exoskeletons every now and then, and leave bacteria wherever they go. 

Malfunctioning Sump Pump Cover 

If you have a sump pump in your basement, it should always be covered with an airtight lid. Otherwise, children or small animals could fall into the sump pit. In addition, the smell of the water present in the pit can spread all over the basement, and even move into your living space. 

The problem with an uncovered sump pump is that it can increase humidity levels in your basement and trigger all the problems listed above. 

Problem Signs In the Basement 

Noticing a weird, musty smell in your basement probably won’t help you determine where the cause of the problem is. Since a bad odor is a telltale indication that something bad is happening in your basement, you should keep your eyes open for the following signs as well.  

Standing Water 

Standing water, mold, and rot go hand in hand. Puddles of water on your basement floor are an obvious sign that something is wrong. The problem here is that so many things can cause standing water, from damaged windows to leaky pipes. If you notice puddles in your basement, call Foundation Systems of Michigan and our professionals will determine what is aching your home. 

Spreading Cracks 

Most homes have numerous hairline cracks. When the house is built, it needs some time to settle, which is when these cracks appear. Over the years, they do not widen or get bigger in any way. However, if you notice cracks that would easily swallow your credit card, it is time to consult a professional. These cracks are a sign that something is seriously wrong with your foundation and you need to hire an expert who will investigate the situation properly. 

Damaged Drywall 

Are you worried that your basement is becoming damp? If so, simply check the drywall panels in your basement. If they have started to bubble, peel, bulge, or sag, dampness has found its way in. Humidity can cause so much damage, which is why it is essential to waterproof your basement on time. 

Bowing Walls 

Bowing walls are never good news, and if you notice that yours are leaning, you should notify your contractor as quickly as possible. They usually tend to bow from hydrostatic pressure, which is why you should keep your eyes open for dark cracks in the walls. You will most likely notice them before you notice that your walls are bowing. This can be a serious structural problem, so do not postpone the repairs. 

Sagging Floors 

If you notice a weird smell in your basement, pay attention to your beams, joists, floorboards, and anything else made of wood. If humidity levels in your basement have increased, the wood will begin to warp and deteriorate, losing its strength. Eventually, your floors will begin to sag. 

Musty Basement Smell


Now that you know that a musty smell is not something you should just come to terms with, but rather a sign of underlying problems, you are probably wondering how to make your basement smell fresh again. You will certainly find plenty of solutions online, but the problem is that most of them do not work. 

Bleaching the Basement 

A lot of homeowners recommend using a bleach solution to sanitize the basement. While bleach can kill mold, a true solution is much more complicated than just spraying it all over your basement. This process is complex and if you don’t take all the necessary steps, you can put your health in danger. 

Working with bleach can be messy and complicated, and you could easily get hurt in the process. Therefore, instead of dealing with mold yourself, call the professionals. This way, you will be sure that your basement is completely mold-free and you won’t risk your health. 


A dehumidifier is an incredibly useful appliance that can dry out your humid basement and keep moisture levels under control. It is an important part of the mold-removal process, but it shouldn’t be your only method of fixing things. While a dehumidifier can remove humidity – the cause of mold – it cannot remove the already existing mold from your basement. 

Therefore, the right way to use it is to activate it only when the mold is gone and you have properly waterproofed your basement. It works perfectly with other waterproofing methods and can ensure that mold doesn’t appear again in your basement. 

Regardless of whether your basement smells musty because of mold, rot, or pests, there is one culprit that triggers all of these other problems, and that is humidity. If there are increased moisture levels in your basement your wood will begin to rot, mold will spread and pests will move in. So how can you keep your basement dry once and for all? At Foundation Systems of Michigan, we have vast experience when it comes to implementing waterproofing measures. Here are just some of the solutions that can help keep your basement dry. Of course, maybe your home doesn’t need everything from this list. This is why you should always schedule a free inspection and let our professionals determine which solutions will best suit your home. 

Interior Drain System with a Sump Pump 

Installing an exterior drainage system is messy, invasive, disruptive, and expensive. On top of this, this system can clog often, making the situation even worse. This is why at Foundation Systems of Michigan we recommend our AquaStop® Drainage System. This interior drainage system is in charge of collecting the water that enters through the walls and the cove joint, preventing it from causing any damage. Since it is placed below the ground, it is barely visible once installed. Unlike other drain systems, AquaStop® Drainage System sits on the footing, away from soil and roots, so it won’t clog.  It can be quickly installed, is made from durable materials, and will keep your basement dry for decades to come. 

All the water that is collected by the interior drain system is directed into the sump pit. There, a sump pump can quickly discharge the water and send it away from your home. Furthermore, a sump pit can collect water that accumulates below your home and prevent it from spilling all over your basement. Our professionals recommend Pro Series Pumps which feature a cast-iron casing, and not a plastic one that tends to overheat. These pumps also come with a reliable switch that won’t fail the homeowners in the case of flooding. 

Wall Vapor Barrier System 

Another solution in our line of defense against moisture is the CrawlSeal® Basement Wall Vapor Barrier System. This completely waterproof, plastic vapor barrier protects your basement from the water that enters this area through concrete foundation walls. 

This system lowers humidity, prevents musty smells and odors, and resists mold growth. Our wall vapor barrier system also installs quickly and once it is in place, it redirects water leaking through the walls into the interior drainage system. 


You won’t be able to keep your basement dry by only using a dehumidifier. This device should only be used as a part of your waterproofing system. It can make your indoor humidity much easier to manage and prevent mold growth and rot. 

That said, a dehumidifier needs to be strong enough to keep large, humid areas dry. An ordinary dehumidifier you can get at your local home improvement store won’t get the job done. It is designed to regulate humidity levels in areas where humidity is not that high, such as your living room or bedroom. Therefore, contact experts at Foundation Systems of Michigan and see which appliance will keep your basement dry. 

If your room smells like stale air, you would just open the windows and let some fresh air in. Therefore, it is not strange to wonder whether the same strategy will remove the bad smells from your basement. 

More Harm Than Good 

Believe it or not, ventilating your basement can do more harm than good. In fact, in most cases, it will just make the problem worse. When you open the basement windows, you are letting moisture-laden air inside. 

Since increased humidity levels are responsible for mold, rot, or other problems that are making your basement smell bad, you could only make things worse. Locating the source of the problem and addressing it is the only way you can get rid of that stench for good. 

Call the Professionals in Your Area 

Opening the windows and washing your basement with bleach are strategies that are often recommended, but highly inefficient. By opening the windows you can let even more moisture inside while working with bleach can harm your health. 

Instead of taking things into your own hands, step aside and let professionals handle them. Removing mold is dangerous, and only one of the steps you need to take to completely get rid of nasty odors. Call Foundation Systems of Michigan and see which waterproofing measures will help maintain a dry, clean, and safe basement.

Letting the Professionals Take the Lead 

Our professional team of basement waterproofing specialists at Foundation Systems of Michigan have the skills and experience needed to determine the root of your problems and recommend the best solutions for them. They are not salesmen, and they will never recommend something you do not truly need. Our staff provides friendly, thorough inspections throughout the entire Lower Peninsula and the Eastern Upper Peninsula in Michigan, as well as in Northern Ohio and Toledo. We offer flexible finance options so do not hesitate to check out our award-winning services. After our no-obligation inspection, you will receive same-day written quotes, so you can immediately find out which solutions will allow you to restore your home to its original state. We have been working with musty-smelling and moldy basements for over a decade, so there is nothing we haven’t seen and fixed before. Request an inspection today and get to the bottom of the problem with help from our experts.

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