How To Prevent Mold In The Basement + 13 Basement Mold Tips

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Basement mold is a widespread issue. In fact, mold inspectors and remediation companies see more extensive problems with basement mold than in any other part of the house.

Because basements are built below ground level, moisture will always be permeating the building either through the walls or the foundation or through window wells. This is a function of the moisture in the soil surrounding the basement. Since these are the lowest parts of the home, gravity dictates that if water is present, it will flow towards the lowest area to settle.

If you have a basement you need to take extra precautions to not only look for signs of mold but also to prevent mold in the basement.

A mold free basement because the homeowners followed a guide on how to prevent mold in the basement.

There are 4 primary reasons for the increase in basement mold.

  1. After about 20-30 years of age, many building foundations made from concrete begin to see some cracking, which leads to water penetration. As you know, mold likes water. Around this time buildings also begin to settle which means there could be a change in how level the basement floor is.
  2. Lack of a sump pump, cheap sump pumps, or poorly maintained sump pumps.
  3. In older homes, many basements were never truly designed to be finished but finishing a basement has become a popular renovation item. Older basements are not water-tight and many homeowners and even contractors didn’t know or didn’t bother to waterproof the basements prior to building them out. In addition, when basements are finished, often times there are issues with framing at the joints. This is because two dissimilar materials come together (think wood attached to masonry). Every material expands and contracts at a different rate over time and moisture problems easily develop where these materials meet each other.
  4. Lack of proper grading, rain gutters and downspouts.

How Does Moisture Get Inside A Basement?

There are two main sources of water in basements, neither of which should surprise you. There is an outside moisture source and an inside moisture source.

Outside moisture sources are things like floods, rain, and groundwater. An inside moisture source could be anything from a leak to high humidity to homeowner negligence and poor practices (such as leaving wet towels in a pile in the basement).

Where Mold Grows in Basement

Some of the most common places where mold grows in the basement are:

  • Ceiling
  • Ducts and vents
  • Floor
  • Furniture
  • Insulation
  • Pipes
  • Storage boxes
  • Wall cavities
  • Walls
  • Wooden building frames

Signs of Mold in The Basement

One of the clearest signs that you have mold in your basement is the smell. Because of the stagnant air in the basement, odors build up and become very noticeable. If you smell mold or even a slightly musty odor, you likely have basement mold.

Musty Smell In Basement

How To Prevent Basement Mold

These 13 ways to prevent basement mold are all critical to a healthy, mold free basement. My guess is that there are quite a few mold prevention tips here that you are overlooking. Never fear – know better, do better. Let’s get to it shall we?

  1. To avoid wet floors and standing water in your basement, install a high quality sump pump like this one with a battery backup system and a perimeter drainage canal.
  2. Insulate water pipes in the basement. Generally, cold water pipes in the basement show condensation on the exterior. Insulating pipes in sleeves or fiber glass reduces the humidity levels in the basement.
  3. The best way to reduce high humidity and condensation in basements is to deep-seal your concrete against moisture. Sealing the basement slab (and below grade walls) against water vapor transmission and possible water seepage is the key to preventing mold and mildew. What you use to seal the concrete will make all the difference.
  4. Window wells in basements are often covered. The covering does prevent rain water from coming in but it also prevents proper ventilation. It is best to use window well covers that have a ventilation system. Take covers off monthly to air out your basement.
  5. Speaking of airing out…Get some fresh air exchange weekly if possible. If you have windows or an exterior door into your basement, open those up and allow the stagnant air to move out and the fresh air to move in.
  6. Keep any back-basement stairs clear of leaves and add a drain cover to prevent blockage. Basement mold can easily start from wet fallen leaves that have covered the drain pipe on the outside stairway leading to the basement.
  7. Inspect the basement for cracks monthly and fill cracks immediately.
  8. Add this mold inhibitor to paint or select a mold resistant paint.
  9. Avoid carpet and wood flooring in your basement. Tile flooring or even vinyl flooring are better options since they are less prone to mold growth. The best option is to simply seal and waterproof the concrete.
  10. Never vent appliances such as dryers, stoves, heaters, and air conditioners inside the basement. This also leads to high humidity and condensation. Always exhaust them to the outside. In addition, never dry wet clothes in the basement. This leads to high humidity and condensation.
  11. Be storage savvy. Keep your basement free from clutter. Too many objects and storage items block the free flow of air and reduce ventilation. Items such as clothes and books stored in the basement are food for mold and mildew. Also keep in mind that wet boxes are a nightmare to deal with. It is best to store items in plastic totes. These should sit on wire racks/shelves 6 inches off the ground and 6 inches away from walls.
  12. Avoid storing wood in the basement. Wood is ideal habitat for mold. Not only does it contain moisture but it is the perfect organic material (aka food) for mold spores. Never store wood in the basement.
  13. Spray your basement with Endurance BioBarrier to prevent mold growth. You can read how and why this works as well as how often you need to use the spray in my Endurance BioBarrier Review post. It really works and comes with an amazing guarantee.
Cluttered Basement - not the way to prevent basement mold
This cluttered basement is NOT the way to prevent basement mold!

How To Fix A Basement Leak Due To A Crack In The Wall or Foundation

Leaks happen. Especially basement leaks. But never fear. There are ways to fix a basement leak due to cracking and in turn, prevent mold from growing in the basement. These 5 simple steps will have your basement in tip top shape in now time. Remember – time is of essence so it is important to fix a crack quickly.

Home improvement types can likely tackle this on their own. But for the rest of us? You probably want to at least consult with a contractor if not hire one to make these repairs for you. In any event, the process will be the same.

Let’s repair that basement crack shall we?

1. Locate the Leak – The source of a leak is not necessarily in the same place that you found water. Trace the water to its source either coming up through the foundation or in through the wall. Remember, there may be more than a single entry point.

A basement leak from the foundation with standing water

2. Inspect The Crack(s) – Using a hammer and chisel, carefully open any cracks or voids. Inspect them for extensive damage or holes. Remember that the cracks which you saw on the exterior walls and foundation of your basement are not the total extent of the damage.

3. Remove Loose Debris – Use a small brush to remove loose debris in the crack. Once you get rid of as much as possible, use a can of compressed air for a final clean out.

4. Apply Hydraulic Cement – This is usually where most DIY types call uncle. Please make sure you know what you are doing and always wear protective gear.

Mix hydraulic cement per the instructions on the packet. Apply the mixed cement to the crack, pressing it in as far as possible. Ensure that the cement doesn’t protrude from the wall.

You must use the hydraulic cement within 10 to 15 minutes of mixing it. You have to work quickly and thoroughly. To obtain a flatter finish to the wall or foundation, use a mortar trowel to apply the cement. Leave the cement to cure for 48 hours or more.

5. Waterproof The Walls – Once you have filled the cracks, apply a waterproof sealant to protect against future damage. These sealants should be applied to a wet or damp wall. They must dry completely before you apply a second coat.

There you have it! Everything you need to know about preventing basement mold. I know it seems daunting but caring for your basement is important to the entire health of your home.

If you are looking for more information on leaks, check out my post on the Common Places Water Leaks In Your Home. You might also find my article on Preventing Bathroom Mold helpful.

A wet basement, a water damaged basement, a moldy basement. Prevent mold in the basement. Prevent leaks in the basement.

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  1. Tyler Johnson says:

    That’s a good idea to get someone to help fix the leak right away. I could see how that’s would prevent the mold from growing, as well as avoid any other damage. Next time I have a basement leak, I should get someone to help me do that so I could avoid any mold.

  2. Braden Bills says:

    I’ve been having issues with water damage in my basement, and I’m not sure what to do about it. It makes sense that getting a professional to help me out with this would be beneficial! It would be so nice to not have to worry about mold anymore.

  3. Adam Golightly says:

    My uncle thinks that he has found some mold behind the couch in his basement and he wants to make sure that he can be a lot safer and prevent further damage. Getting some help from a professional could be really useful and allow him to get an inspection so that he will know that there isn’t any more around the area. I liked what you said about how he should get some fresh air in the area so that it can reduce the moisture and move the stagnant air out.

  4. Carrie N. says:

    You mention that what you use to seal the concrete in the basement will make all the difference. Do you have any recommendations? We have an old concrete floor in a 100 year house. Thank you!

    1. Hi Carrie! This product is a great one: Definitely shop around on price because it can vary from store to store.