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Can a Damp Basement Affect Upstairs (Act before it’s too late)

A poorly-maintained basement is musty, damp, and avoided at all costs. Sometimes, it’s not even just negligence; keeping it dry and clean seems to be an uphill battle, and people often give up on it. However, a damp basement is more than uninviting; it can dangerous and affect the rest of the house.

From adversely affecting your home’s structure to causing some serious health hazards, the list is endless. In this article, I explain why you should be concerned about your damp basement and the best possible solutions to reduce humidity.  

Basement damp can spread through the walls and ceilings into the upstairs. Soggy walls and ceilings are weak and can collapse (whether on the main floor or in the basement). Damp breeds mold, further compromising the structure and posing health risks. Mold can move upstairs. Damp basements make houses cold.

Damp Spreads Through Walls and Ceilings

There are outdoor as well as indoor moisture sources that are responsible for your damp basement. Moisture accumulated from appliances like dryers, humidifiers, coolers, rain or groundwater seeping inside through the cracks, and humidity from ventilation are the primary reasons why there is moisture in your basement.

A Man removing Mold fungus with respirator mask

Wooden frames in your basement walls, drywalls, ceiling boards, etc., absorb moisture and make your basement structure damp.

You can opt for wooden frames made with pressure-treated wood, particularly for the bottom plate, which are resistant to rotting or moisture-resistant drywalls that reduce the chances of basement moisture and associated problems like mold, mildew, etc.

Even stone and masonry that has not been waterproofed can absorb moisture and cause structural damage to your property. Water seeps into the stone and masonry, making the brick more porous and causing moisture to travel from your basement to the rest of your house. 

Moisture from the basement can creep through the walls and ceilings (particularly if the source of the damp is not promptly addressed), climbing higher and finally reaching the upstairs structures. A damp basement is capable of ruining your house and costing you lots of money in repair.

Soggy Walls and Ceilings Are Weak

Most people think that faulty construction is the reason for water seeping in and causing dampness in the basement. The truth is, your house could be built to perfection, and yet moisture can get in. Sometimes, cracks happen due to the pressure created by the water build-up.

No one likes soggy walls. A little bit of rain causes ugly wet spots to appear on your walls, giving your space a shabby look. A damp basement not only reduces the aesthetic appeal of your place but will also surely cause damage to your beautiful home.

The basement is usually the first place in a home to become damp. Once moisture seeps into the basement wall or foundation then the entire structure starts becoming weak. You know your ceiling is getting damaged due to moisture when it starts sagging, paint starts peeling off, or cracks start appearing.

If a damp basement is left unattended for too long, then someday you might end up with some of your upstairs, downstairs!

Even if the basement is fine, the creeping moisture can weaken the walls and floor upstairs and cause them to break and buckle.

Furthermore, a ceiling has wires, joists, pipes, etc., that get damaged by the presence of moisture.

Damp Breeds Mold

Mold thrives in places that are damp, dark, and wet like a damp basement. One of the worst consequences of a damp basement is the breeding of mold. Once a part of your house gets affected, then chances are there that mold spores have already spread around your home.

Mold spores float in air, entering your home through vents, windows, and air conditioning systems. Once they enter, they settle on wet surfaces and then spread all over your beautiful home.

Mold needs water to grow and spread. If your basement is damp due to leakage or any other reason, then mold infestation is bound to happen sooner or later. The thing about mold is, you can smell it when it starts spreading in your damp basement.

Apart from damaging your house, mold infestation is capable of causing some serious health hazards (more on this later).

Female worker of cleaning service removes the mold using antimicrobial spray and scrubbing brush

Mold Can Travel Upstairs

The natural or HVAC-generated air movements through your home cause mold from your damp basement to travel upstairs and find new breeding grounds. These spores are airborne and spread with the moist air released from the basement. Sometimes, you can even carry molds on your feet or your shoes and transfer them upstairs.

Basements are that part of the home that is seldom cleaned and is packed with unnecessary things. Hence, mold infestation often goes unchecked and untreated for a long period. Over time, mold contaminates areas near the breeding spot.

If there’s mold on the wall, then there are chances that it will spread to the ceiling, door, door frame, and more. Mold spores latch on things that are damp and start to breed there.

Appliances with air ducts like air conditioning and heater draw in mold spores. Eventually, mold starts growing in the air ducts and reaches upstairs. Mold is an indoor air pollutant and can cause several long-term and short-term health hazards. It commonly causes respiratory problems and affects the residents as well as animals living in that house.

Health Risks of Mold

You know you have a mold infestation problem by two things. First, the earthy, musty smell that’s hanging in the air, and second, when your family members start showing symptoms like regular sneezing, eye irritation, and coughing.

Mold is known to be a health risk. It causes health problems especially related to the respiratory system. If you are exposed to mold spores, then chances are, you will develop certain allergy-like reactions like skin rash, headache, coughing, sore throat, and runny nose.

As per the Institute of Medicine (IOM), when healthy people come in direct contact with the mold, they develop upper respiratory tract symptoms. It also triggers asthma symptoms, like difficulty in breathing in people with asthma, and can lead to an asthma attack.

People with existing health conditions like asthma, lung disease, chronic obstructive pulmonary disorder (COPD), and allergies are more at risk of getting adversely affected by mold.  

Mold is also harmful to your pets. Dogs and cats often come in direct contact with mold spores as they tend to lick surfaces and chew on things. Mold poisoning can cause serious allergic reactions, respiratory problems, gastric symptoms like loss of appetite, vomiting, fur loss, sores, excessive scratching or licking, and many other problems.  

You must take mold infestation seriously and get rid of it at the earliest for the safety of everyone you love and care about. And permanently dealing with mold infestations starts with clearing up damp in your basement.

Upstairs Can Become a New Breeding Ground

Molds are always looking for new breeding grounds. When they travel from your damp basement to the upstairs, they find new places to grow. As mentioned earlier, any place that’s dark, damp, and dingy is where they are likely to settle down.

Once mold spores reach upstairs they find new breeding grounds. A leaky roof or window, water-damaged shower pipes, surfaces with layers of dust, cracked tiles where moisture has accumulated, rotten wooden frames, on or under carpets and floor mats, and filing cabinets.

Molds also grow in home appliances that tend to preserve moisture, like washing machines, dishwashers, and air conditioners. The list of places is endless. Mold will take up residence in any place which is dark, moist, and warm.

You spend lots of time, energy, and money on making your home aesthetically appealing. Now, once mold enters your home, the beauty of your space will be compromised. Peeling of paints, cracks on walls or ceilings, warping, rotting of frames, joists and columns, stained wall—there are countless ways for mold to ruin your beautiful home.

Mold spores penetrate porous surfaces like drywall and insulation and weaken the structure of your building. Wood gets most affected because molds can feed as well as grow on wood. Molds cause damages that require costly repairs.

Cold Is Heightened by Moisture

Every time you open the basement door, a gush of cold wind rushes to welcome you (or hit you in the face, depending on the season!). Even walkout basements, which seem more like regular spaces, are often colder than the rest of the home.

Moisture and humidity will make your basement colder than the rest of your home. The moisture in the air makes the warm air rise up and the cold air settle down, resulting in low temperature.

A damp basement can make your home colder than the normal temperature. So, whenever you open the basement door, warm air gets pulled down from upstairs (temperature gradient), making the upstairs colder in winter. To keep up with this, your heaters will also be working overtime.

Moisture Compromises Insulation

When it comes to insulation and unfinished basements, the International Residential Code says that the basement must be insulated, or the rest of the house must be insulated against the unconditioned space.

If your house was insulated against the basement, then moisture from the basement may be able to get into this insulation, compromising its function. This not only makes the house non-code-compliant, but it increases heat transference and energy usage.

Tackling Damp in a Basement

Prevention is always better than cure. The best thing to do is regular checks of your building for mold infestation and water leakage. This way, you can ensure that there is no mold growth, or even if there is, it’s treated at the earliest to avoid serious problems. 

There are several ways of dealing with a damp basement. Some of them are:

Exhaust Fan/Dehumidifier – If your basement has a kitchen or a bathroom, then installing an exhaust fan will ensure excess moisture is vented out.

In some rare cases, ventilation won’t be enough and a quality dehumidifier that drains directly into the floor drain is the best option. Avoid dehumidifiers that collect water into internal containers as they have to be emptied often. A built-in dehumidifier(pictured below) with automatic humidity control is best for finished basements.

Waykar 158 Pints Crawl Space Dehumidifier, Commercial Dehumidifier with Wired Remote Control, Auto Defrosting, Industrial Dehumidifier with Carrying Handle for Basement and Whole House.
  • EFFICIENCY & LARGE CAPACITY: This crawl space/basement dehumidifier is designed to extract up to 158 pints of moisture daily with high efficiency, without adding to your energy bill. Suitable for...
  • CORROSION PROTECTION: This dehumidifier features an internal corrosion protection coating that safeguards the internal metal components from humidity-induced corrosion. This unique feature extends the...
  • AUTO-DEFROST FUNCTION: Equipped with an automatic defrost feature, this dehumidifier detects and melts ice on the evaporative coils, maintaining its efficiency and prolonging its lifespan. This...
  • WIRED CONTROL PANEL & SENSOR: The wired control panel offers easy access and control without the need to enter tight crawl spaces. The sensor provides accurate humidity readings, enabling precise...

Last update on 2023-12-05 / Affiliate links / Images from Amazon Product Advertising API

Repairing Cracks – Cracks on walls, ceilings, or foundations cause moisture to seep into the basement. Filling up cracks is an inexpensive way of taking care of a damp basement.

Sikaflex Crack Flex Sealant, Gray, High performance, textured polyurethane sealant, self-leveling, sealant for sealing horizontal cracks, 10,1 fl. Oz

Waterproofing – You can always waterproof the walls of the basement using a waterproofing masonry sealer.

Insulation – Insulating pipes, walls, and ducts where moisture collects frequently.

Increase Ventilation – When you have proper air circulation in the basement then it gets difficult for moisture to settle down. Don’t let the lack of windows make you give up on ventilation. Windowless basements can still be well-ventilated whether permanently or just temporarily).

If the water is starting to gather and pool, you may have to look into a sump pump, waterproofing, or both.


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