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Leaking Basement Floor

Finding water all over your basement floor without any obvious explanation is more than a little unnerving. What causes a leaking basement floor? Let’s find out!

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A property’s basement can either be a great boon or a huge pain in the neck, and there is rarely a happy medium. While your basement offers a wealth of storage space and the chance to expand your livable square footage, it is also vulnerable to issues like hydrostatic pressure, seepage, and general dampness. This is because of its subterranean position. Unlike the rest of your home, your basement must contend with the pressure of the soil around your home (as well as all the water that it holds). 

What pressures does your basement face? How can you recognize red flags before they escalate into serious issues? Let’s dive into all you need to know. 

Your Basement and Foundation are Closely Tied 

The first thing you should know about your basement is that it is closely tied to your foundation. When damage starts to show in your basement walls and floor, it is likely that the source is within your foundation. 

This means that your basement acts rather like a canary in a coal mine when it comes to foundation damage. When issues like settlement, frost heave, and subsidence damage your foundation, your basement floor and walls act as the visible face. After all, it’s not always possible to quickly inspect your property’s foundation. 

Causes of A Leaking Basement Floor 

If you have noticed that your basement floor always seems to be wet, or you have found pools of water across the basement floor for no obvious reason, it can be very worrying. Dampness and humidity are some of the most basic signs that something is going wrong in your home. Unfortunately, this also means it can be hard to figure out just what is causing your basement floor to leak. 

Let’s assume there is no chance that the water is coming from an internal source. For example, this would include a damaged appliance or leaking pipe. In that case, here are the most likely culprits. 


It is very common for a property’s foundation and basement floor to be made of poured concrete. This is, after all, one of the most widely used construction materials thanks to its impressive strength and durability. Unfortunately, poured concrete has one main weakness: It is incredibly porous. 

Porous materials like concrete can absorb water over time. If your property sits in a very wet area where there is a lot of hydrostatic pressure, a process called ‘seepage’ may take place. Seepage is what occurs when water literally seeps through a concrete wall or floor into your home. This process usually doesn’t damage the surface in question, but it can let a surprising amount of moisture into your home. 

Foundation Settlement 

Settlement shouldn’t be confused with the natural settling of a newly built home. Instead, it’s most often caused by the shrinking of expansive soils. Expansive or reactive soils are those that are highly absorbent and change in volume depending on their moisture content. Clay-based soils are a perfect example of this because of the way that they swell and shrink depending on their level of saturation or dehydration. 

When expansive soil becomes very dry—for example, during a drought or heat wave—it can shrink sharply and leave sections of your foundation unsupported. When this happens, it is possible for sections of your foundation to break away and settle into the gap. When the soil becomes saturated once more, these cracks in your foundation will act as channels for water. If the basement floor above is intact, the water may begin to seep through over time. If it has been damaged too, the water will make its way into your home through the cracks. 


Subsidence is a process of sinking that can happen for a number of reasons. While it is most common in very heavy buildings placed on marshy soil, it can also affect lighter structures or be caused by expansive soils. All it really needs is for the property in question to be built on soil that is fundamentally unable to support it. Over time, properties in this situation will begin to sink. 

Of course, it is very unlikely that the property will sink in a uniform fashion. When a property sinks unevenly, extra strain is placed upon certain areas of the home and cracks start to form. The basement is often the first place to see such damage, and spreading cracks across the floor and walls are a common sign of subsidence. As with settlement, these cracks act like channels for trapped moisture and can allow water into your home. 

bowing basement wall

Bowing Walls 

Bowing walls are a common issue in homes that are struggling with hydrostatic pressure. As the lateral pressure makes the walls in question crack and bulge inward, they can start to push against your basement floor, causing cracks to form. If this is the reason for your leaking basement floor, you will be able to tell very quickly, as the walls will be leaking too. 

A noticeable bulge or lean will also form over time. If left without intervention, this may cause walls to break away from the ceiling. That will lead to the floor above your basement starting to sag and dip as well. 

In cases where large amounts of water are entering a basement via the floor, it is very likely that there is more than one contributing factor at work. As such, it is important that you act quickly when you see any warning signs or red flags. 

Warning Signs 

The warning signs of a leaking basement floor are fairly simple and easy to spot. As well as the obvious presence of water on your basement floor, you can also look for: 

  • Spreading cracks that appear to be seeping 
  • Condensation on the walls and windows 
  • High indoor humidity 
  • Mold formation 
  • Leaning or bowing walls 

Of course, these can also be symptoms of other issues. Because of that, it’s very important that you prioritize a full investigation of the issues at hand. This is the only way to be entirely certain of what is causing the dampness within your home. 

Leaking Basement Floor


If you have noticed a strange, musty smell in your basement that no amount of cleaning can solve, it is likely that you have an issue with dampness and humidity. Learning to isolate the potential sources is important. 


Seepage is a unique process by which water seeps through porous materials like poured concrete. If you notice your basement floor or walls are always damp to the touch (and there is no other obvious source for the water in your home), it is very likely that you are dealing with seepage within your home. This is both a blessing and somewhat of a curse. 

You see, seepage is not overly destructive to your floor or walls. A concrete structure does not need to be damaged for seepage to take place, and the process itself is unlikely to cause damage. This is good for your home, of course, but not so great for you. Because seepage doesn’t come from one particular source of damage, it can be frustratingly difficult to handle. In the case of seepage, the only real solution is often to opt for a full waterproofing process within your basement. 

Structural Damage 

There are many potential causes of dampness and humidity in the average basement. Internal leaks are always a possibility, of course, but they are also fairly easy to spot. A burst pipe, after all, is far from subtle. Structural damage, by contrast, can be far harder to identify and diagnose. Foundation damage, leaking window wells, and cracked walls can all let water into your home. 

Each of these issues has a unique set of tells that can help you to identify them and a set of likely underlying causes. This is why repairing and waterproofing a wet basement can be so difficult! As well as all of this, there is also a process called seepage that can see water seep through porous but undamaged concrete, making it incredibly difficult to deal with. 

Mold and Mildew 

Mold and mildew require humidity, dampness, and organic material to form in the first place. This makes a damp, non-waterproofed basement a perfect environment for mold. When mold and humidity come together in a space, they can create a unique and strong odor that is often described as musty and slightly sweet. 

This smell is only exacerbated by issues like wood rot and pest infestation, which are more common in damp basements that are struggling with mold problems and structural damage. As such, you should get a professional to investigate the source of this smell as soon as you notice it. This will give you a chance of dealing with it before it escalates. 

Basement waterproofing is one of those things that most professionals will suggest to you at some point. This is not a matter of money, however; experts suggest waterproofing because it is a genuinely beneficial process. 

Structural Protection  

Basement waterproofing is one of the most basic things you can do to protect your home from avoidable damage and dampness. Water damage is one of the most destructive things that can happen to a property. From mold and mildew to wood rot and damage to wooden flooring, furnishings, and appliances, a damp basement can cause many issues. 

Waterproofing measures like vapor barriers and dehumidifiers can protect you from more than moisture. A high-quality vapor barrier, for example, will also make your basement more resistant to pest intrusion. Likewise, a dehumidifier will protect you from some airborne allergens and create a more pleasant environment in your basement. 

Energy Efficiency 

Waterproofing your basement will also have a tangible effect on your property’s energy consumption. First and foremost, effective insulation is often a part of the waterproofing process (unless it is already present). Secondly, reducing the level of relative humidity in your property will make your HVAC system far more efficient. 

This is because of the way that humid air reacts to heat and cold as opposed to arid air. Humid air is far harder for your HVAC system to process and heat or cool because of the moisture it holds. Arid air, by comparison, is very easy to process. As such, waterproofing will let your HVAC system take a break, thereby using less energy and costing you less money. 

Peace of Mind 

Professional waterproofing might be an expense you didn’t plan for, but it could save you huge amounts of money in the long run. Firstly, it will reduce the overall humidity in your home. This will make the environment healthier, more comfortable, and kinder to your HVAC system. Secondly, waterproofing will make pest infestation and mold formation far less likely. This will save you money on future repairs and even your energy bills. 

Waterproofing will also help to stabilize the temperatures inside your home and can prevent less widely discussed issues (like the stack effect) from taking root and causing problems. In short, when you pay for basement waterproofing, you are buying peace of mind, because you are taking preventative measures to protect your home.  

In theory, it should be possible for a skilled homeowner to waterproof their basement. However, there are many dangers to both yourself and your home that make it inadvisable. It’s far better to have professional help for a number of reasons. 

The Best Products are Hard to Get 

If you decide to waterproof your basement, you will quickly realize that getting the best products for your home is all-important when it comes to getting the right results. That’s because the right products tend not to be available over the counter in a hardware store. This means you really need a professional on your side to get the best deals. 

Furthermore, even if you can find a store with specialist, industry-grade products, it can be hard to find out just what you need for your property. If you buy a product that is not suitable, you could end up paying far more than you need to – or worse, still not getting the results that you need from the process. As such, it’s better to have someone in the know on your side. 

DIY Waterproofing Can Go Wrong 

The process of basement waterproofing is not always invasive or intensive, but it can be. Furthermore, there are many tasks that are delicate, difficult, or that require special tools for proper completion. Tackling these tasks as an amateur can be daunting and even dangerous, as well as costly if you intend to hire or rent the necessary tools and equipment. 

As well as the obvious possibility that you could damage your home or the products you have bought during installation, there is the chance that you could install them incorrectly. This can be surprisingly damaging. Installing a vapor barrier improperly, for example, can result in you trapping moisture inside your home. This will create a very unhealthy environment for you and your property. 

There are Benefits to Professional Help 

One serious benefit to having professional help that few people ever talk about is the convenience that it offers. It’s all fine and well to be money-savvy or skilled at DIY, but a professional service is quick, easy, and efficient. Experts can undertake work in half the time that even a skilled amateur would need, and they will do it with minimum disruption to your home and your day. 

Secondly, professional services come with support and guarantees of quality. When you buy products and appliances through a repair service, you also get warranties and guarantees (sometimes transferable) that protect you from breakdowns and faulty products. You can also rely on an expert to tell you how to make the most of products that you are unfamiliar with. So, as you can see, there are some good reasons to choose a professional service that transcend cost. 

How to Deal with a Leaky Basement Floor 

If you have a consistently damp basement with a leaky floor, the first thing you should do is perform your own investigation. While it is unlikely that you will be able to fully diagnose the issue, you can take note of all the warning signs that you see. This will help the professional you contact get a handle on the situation quickly. 

Look for things like large cracks, puddles of water, and mold formations. Make a note of where in the basement they appear. Once you have done this, you should remove any valuable or sentimental items from the area to prevent them from becoming irreparably damaged. 

Contact a Professional 

Contact a professional as soon as you can and arrange a proper assessment of your basement. When the inspector arrives, provide them with all the information you have and give them the space they need to properly assess the damage. Once they have completed their inspection, most professionals will have an idea of what is happening and how to fix it. They may suggest further exploration, but this is not overly common. 

We know it can be tempting to go it alone, but DIY is a bad idea. Issues like this tend to be complex and can involve structural damage that requires specialist repair tools and products. This is doubly the case if you feel your foundation might be the underlying cause. Foundation repairs are dangerous and intensive. They require heavy excavation, and if you get them wrong, you could injure yourself, someone else, or cause huge damage to your home. 

Consider Waterproofing Your Basement 

basement gutter with level

Even if the main cause of your leaking basement floor is structural damage, waterproofing is still a fantastic idea. As well as being a relatively simple and easy process that a professional can undertake in a day or less, waterproofing will protect your home from all kinds of issues going forward. Something as simple as installing a floor drainage system can go a long way toward preventing the recurrence of dampness and humidity. 

This will protect your home from mold and mildew, wood rot, and strain on your HVAC system as a result of high relative humidity in your property. The list of benefits to waterproofing goes on and on. Of course, the precise benefits you will see depend on your home and your current situation, but it is a generally good decision to protect your home from dampness. 

Waterproofing your basement is also easy. There are many basement waterproofing specialists in and around Colorado Springs and Denver. Don’t be afraid to look around for a contractor that you feel is going to serve your interests best. Ask questions, get quotes for the work, and do some of your own research until you feel ready to make a choice. It is important that you feel confident you are making the right decision for yourself, after all. 

Contact Complete Basement Systems for Professional Waterproofing 

If your home is being plagued by dampness, humidity, and mold because of a leaky basement floor, removing the signs (and smell) of damage may seem like a losing battle. This is where Complete Basement Systems comes in. We are the premier basement waterproofing specialists in Denver and Colorado Springs. 

Basement waterproofing can be surprisingly easy and cost-effective when you have the right team on your side. Get in contact for a free, no-obligation inspection appointment. You will receive a same-day written estimate for our suggested repairs. Our skilled team will ensure you have all the information you need to make the right choice for your home. 

Our Basement Waterproofing Experts Can Help

Schedule free inspection
Schedule free inspection
Our Basement Waterproofing Experts Can Help

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