Can Mold In My Basement Affect Upstairs? Mold Guide

Can mold in basement affect upstairs? This is a common question among people who have mold forming in their basements. Mold has nothing but negative effects on your property and family. It not only destroys your valuables but also causes health issues for your loved ones. You cannot escape these health problems even if you are living upstairs. 

can mold in basement affect upstairs

Why is the Basement Affected With Mold?

There is a higher chance of mold forming in basements because it is dark, damp, and cool by nature. Since the basement is not cleaned as often as the other parts of the house, there are many things on which mold can grow. The condition and usage of the basement also have an impact on this.

Some people use the basement for excess food storage, living space, and laundry room. Mold formation is excessive in basements that are partially finished and left unused. If the soil around your house is moist, then there is a high tendency for the moisture to seep into the concrete walls if proper waterproof seals are not used. If continuous streams of water inside the basement are left untreated, it will lead to mold and bacterial growth causing health issues. It is important to keep your basement clean just as much as you focus on the other areas of the house.

black mold in basement

Can Mold in Basement Affect Upstairs?

Mold can travel very easily through the house and spread to different areas in your house. Due to the extremely light weight of the mold spores, they can land on your clothing, or pets’ fur, or even travel through the air. When it encounters a damp spot, it will start to grow in that region just as it did in the basement. So, if you have a moldy basement, it is important to keep your house dry and well-ventilated with adequate sunlight to prevent it from spreading. 

What is the Stack Effect?

The stack effect is the way in which air travels through the house. When the air gets heated up inside the house, the hot air rises and travels through the house before leaving through the roof. When the old air leaves, new air rises to fill the space. Although air circulation inside a house is good, if the house is already infected with mold, then the air rising up may carry mold with it. When air is contaminated with mold spores, it can rise up with the air and settle on different parts of the house including upstairs. In this way, mold can escape from the basement even if you haven’t carried anything with mold from the basement to an upper flow.

black mold in basement

What Does Mold Look Like?

Mold is a fungus that is released as tiny spores that flow in the air. It often appears as white spots or stains on ceilings, carpets, surfaces, wallpaper, and paint. It can also grow on other surfaces including wood, paper, cloth, and dead animals. It’s not always white or black mold in the basement as there are many different types of mold in various colors and textures. It might be difficult to tell these types apart. The following are some of the mold types that affect your basement.

  • Chaetomium: It has a fluffy and cotton-like texture, and will often change color over time. The color changes from white to grey to brown to black.
  • Aspergillus: This is the most commonly found mold among households in the US and has many different colors. This belongs to a large family of molds that has over 185 different species.
  • Alternaria: It is a velvety-textured mold that often sprouts out hairs in dark green or brown.
  • Cladosporium: This is an olive-green to brown-colored mold with a suede-like texture.
  • Penicillium: This mold can be identified clearly with its bluish-green coloring and velvety texture.
  • Stachybotrys: This variety is not found commonly in homes since it requires constant, copious amounts of moisture to grow. It is also known as toxic black mold, and appears slim, in a greenish-black color.

What are the Health Risks of Having Mold in Your Basement?

Having mold in your basement is as risky as having it in any other room of the house due to the easy transmission of spores in the air. Although some people are not reactive to mold, it can cause severe allergies in certain people. Exposure to mold can cause various issues, especially among children, the elderly, and people with respiratory conditions. The following are some symptoms of mold exposure:

  • Respiratory difficulties: This may be in the form of coughing, sneezing, shortness of breath, or a blocked or stuffy nose.
  • Eye and skin complaints: Rash-like symptoms such as visible red spots on the skin and even red, itchy eyes.
  • Asthma: Some can even get asthmatic complaints and asthma attacks.

If you have mold in your house and suffer from any of the symptoms above, you might most possibly be under mold allergy. You should consult your doctor as soon as possible and they will determine whether this is the cause after conducting various allergy tests.

How to Stop the Spread of Mold in a House?

The main step in stopping mold spread in your house is to control the moisture and dampness. Here are some recommendations from the Centers for Disease Control and Prevention.

  • Fix leaky roofs, windows, and pipes through which water can enter the house.
  • If your house floods by some means, make sure to clean it thoroughly and dry everything exposed to water.
  • Keep the damp areas of your home such as the bathroom, laundry, and kitchen well ventilated.
  • Try to reduce the humidity levels in your home as much as possible. You can use an air conditioner or a dehumidifier to keep the humidity levels between 30% and 50%.
  • Do not use carpets in rooms or areas that typically have a lot of moisture. This includes bathrooms and basements.

Cost of Mold Elimination

The cost of mold removal varies with the extent of area, location, and complexity of the issue. The average basement mold removal cost using professional mold remediators will cost between $500 and $3,000. This cost can even increase if there is mold in a large area including carpets and drywall. There will be additional costs if you need to seal the foundations. The average cost for sealing the foundation will be around $2,100 – $6,000. 

You can try to remove it on your own if the mold is only within a small area. According to the Environmental Protection Agency (EPA), you are safe to remove mold patches less than 10 square feet (which is roughly 3ft×3ft). If you are trying DIY methods for mold removal, it will cost only around $50 – $300. But the outcomes of the two approaches may vary significantly. Although the cost is low, most homeowners will not do a fair job in trying to eliminate mold by themselves.

Can I Remove Basement Mold With Bleach?

If you want to try a DIY method, you can remove the mold using household cleaning supplies such as bleach and dishwashing detergent. When removing mold in your basement, you often have to deal with drywall and concrete. Use the following steps to remove mold effectively from your basement.

Note: You should definitely wear proper personal protective equipment before starting the mold removal process at home. The PPEs include a mask, rubber gloves, safety eyewear, and sturdy enclosed shoes.

  1. First, prepare a solution by dissolving 1 part dishwashing detergent, 10 parts of bleach, and 20 parts of water. 
  2. Then apply this solution to the moldy area using a sponge or mop. Do not over-saturate the surface. 
  3. Leave the solution on the moldy area, and let it air dry completely.

Frequently Asked Questions

Can Basement Mold Make You Sick?

Yes, mold in the basement can cause allergies and respiratory conditions if you are a reactive person and enter the area. It can also cause health issues even if you haven’t been to the basement since mold spores can float in the air. The air inside your house will carry these spores easily and circulate throughout the house. So, it is important to get rid of mold in the basement as soon as you discover it.

Will a Dehumidifier Help With Mold?

A dehumidifier is a very useful tool in preventing mold growth in a house. It will reduce the moisture level inside your home so that it creates a less desirable environment for mold to grow. But it cannot remove the mold that has grown on a surface.

Will Mold in One Room Affect the Whole House?

Various studies show that mold in a basement can find its way into almost any indoor area of a home. Mold formation is common in basements since they are a common area of flooding and condensation issues. It may greatly affect the health of the residents once the mold spores move around the house. Depending on the reactivity of the individual, mold can irritate the skin, eyes, nose, throat, and lungs.

Can Mold Cause Headaches?

Yes, mold headaches feel like a pulsing or throbbing pain, unlike normal dull headaches. It may worsen with physical activity and especially when you are indoors in a specific building. The symptoms also come as pressure behind the eyes and a tickle in the throat after a few minutes of entering the place.


Hopefully, we have answered your question; can mold in the basement affect the upstairs? It is very essential to remove mold from your basement as soon as you find it. If not, it will gradually spread to the other parts of your house and cause health issues for your family. Keeping your basement dry and free from moisture is the best way to deal with mold formation. Use a suitable sump pump to remove water from your basement during storms. You can also try various water discharge methods to reduce the impact of water on your basement.