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how to get rid of basement mold

How To Remove Mold From Basement Walls – A Step-By-Step Guide

A large-scale mold outbreak can ruin your home and, most importantly, your health. Once an infestation starts in your basement walls, it poses a problem for a variety of reasons:

  • The hideous stains that begin filling up the walls and floor are horrible.
  • The odor caused by the mold spores can be hard to deal with and if left unattended, can quickly take over the whole house.
  • It can infect the nasal cavities and lungs and cause eye irritations.

It also slowly damages the home’s structure, eats away at the foundations, and weakens the overall structure of the building.

If you’re concerned about a mold outbreak in your home, here’s a guide from our team at All Dry USA to help you rid this harmful fungus. If you still can’t clear out the outbreak, call us today for emergency services, we have served countless customers all over the country, especially with mold remediation services.

What Causes Mold in a Basement?

The right breeding conditions are required for mold spores to grow and spread on your basement walls. The following situations can lead to mold growth:

Excess Moisture

Excess moisture due to condensation or leaking foundations creates the perfect mix of oxygen and moisture needed for mold growth. Condensation can also occur due to electrical appliances stored in the space or poor ventilation. The built-up condensation eventually creates a highly humid environment that encourages mold growth.


Leaks can occur due to burst piping or faulty foundations. Sometimes, this is due to aging and infrequent maintenance. Hydro-static pressure caused by a rise in the soil water table will also create a leak in the foundations – leading to basement leaks. Water heaters can also leak sometimes.

In cases of a complete water heater failure, there can be significant flooding, which leads to excess moisture in your basement.


Flooding is one of the significant reasons for mold growth in the basement. Floods cause massive amounts of water to build up, leading to hydrostatic pressure. This, in turn, leads to leaks, moisture, and the resulting mold growth.

Sump Pump Failure

A sump pump pumps water out of the pit and away from your building. This keeps the basement dry and mold-free. If this pump is not correctly maintained, it will stop working correctly. This will result in a build-up of water around your foundation, leading to leaks in your basement. This leads to water damage, the perfect environment for mold to grow.

If your basement has any of the conditions mentioned above, it is wise to test for mold, even if it is not visible to the naked eye.

You can get a do-it-yourself test kit at the local supermarket or call an expert/professional to conduct a test in your home and basement.

Read more: What does mold look like in walls?

Types of Basement Mold

Various types of mold will infest your basement. While they are all hideous, not all of them are toxic to humans.

Molds can be divided into two categories:

  • Allergenic
  • Mycotoxin/black

Allergenic molds usually pose no health risk unless you are extremely sensitive to molds or asthmatic. On the other hand, black molds produce a toxic chemical called mycotoxins and are particularly harmful to humans and pets.

Here are the common types of molds that can infest your basement.


Aspergillus is one of the most common household mold species. There are different types of Aspergillus, and most of them thrive well indoors. Some of the Aspergillus molds are allergenic, but some are mycotoxin and should be removed by a specialist, especially if it is something like black mold.

This fungus is dark green and found on damp walls, ceilings, and even furniture. It flourishes in humid environments, but can also grow in areas that are dry with high levels of humidity or condensation.


Fusarium is found in extremely wet areas. You will find it growing in areas with standing water, damp walls, flooded basement areas, and air vents of humidifiers. It doesn’t need a warm and humid environment to thrive.

It is often yellowish and produces mycotoxins that are harmful to humans and pets. It is also quick-growing and can spread rapidly if nothing is done to arrest its growth.


Cladosporium occurs in areas with high condensation levels. It also thrives in cold environments as it doesn’t need warm, humid conditions to grow. You can find it in shower curtains, window sills, window air conditioning units, and the ceilings of bathrooms.


Popularly known as the “black mold,” Stachybotrys is a mycotoxin and is harmful to humans. It is blackish and has a distinctive musty odor. It is found in areas that are often wet, have low light, and a high amount of moisture.

If you aren’t sure of the type of mold growing in your basement or home, it is wise to seek out a local expert to identify the particular mold spreading through your home.

Read more: How to test for mold in your basement

How To Get Rid of Basement Mold

There are numerous ways to get rid of mold in your home and basement. However, before you start clearing out the mold, make sure you fix the real problem as the mold growth is only a symptom of an underlying problem. This could mean fixing a leak, ensuring that the basement has proper ventilation, and checking that any standing water has dried.

Here are several methods you can use to remove mold from your home and basement.


Vinegar is a great household cleaner that can also be used for removing mold. To be specific, ensure you get white vinegar when thinking of using this solution. Simply pour the white vinegar over the mold and allow it to sit between two to five minutes. You can then wipe off the mold with a cloth or sponge. This works on a variety of porous and solid surfaces.

Tea Tree Oil

Tea tree oil is a fungicide and a terrific solution for eliminating basement mold from walls and other surfaces. Before using tea tree oil, mix the oil with water and then shake well to ensure the solution is mixed correctly. You then spray the mixture on the areas infested with mold and scrub until the mold disappears.

Grapefruit Seed Extract

Grapefruit seed extract is not only great at mold removal, but it also prevents a re-occurrence of the mold infestation. To use this solution, mix the extract with an equal part of water and apply it to the affected areas. Allow the mixture to sit for a few minutes (five minutes should work wonders). Then wipe off the mold with a sponge or dry cloth.

Hydrogen Peroxide

Hydrogen peroxide is a handy and non-toxic solution for getting rid of mold in your home and basement. Mix with water and then spray on the affected floors and walls. Allow it to sit on the mold for ten minutes, and then use a scrub brush to scrub off the mold and mildew.


When using Borax, it is essential to mix it properly as the wrong mixture can be harmful if ingested. You should combine a cup of the Borax solution with one gallon of water. Apply the Borax solution to the affected areas and then scrub using a sponge or a scrub brush. Borax also fights off the musty odors due to its deodorizing properties.

Once mixed properly, you don’t need to bother about rinsing the Borax solution off the surface affected by mold and mildew.


Bleach is an easy-to-use and affordable solution. Once applied, you can be assured that it will kill mold and all the spores. However, it won’t kill the mold roots, so they might regrow if favorable conditions remain.

The disadvantage of using bleach to treat mold infestations is it can’t be used on fabrics or carpets. It can only be used on hard surfaces such as tiles, bathtubs, etc. It can also be toxic if ingested. If the ventilation of your basement is poor, bleach needs to be used with caution.


Concrobium is an EPA-approved mold removal chemical that is non-toxic. While it is less toxic than bleach, it can be expensive. When applied to mold-infested areas, it not only kills the mold, but it also prevents the recurrence of mold spores on surfaces that were appropriately treated. It can also be used on a wide range of surfaces, unlike bleach, such as wood, plastic, stone, tile, and other surfaces.

High-Efficiency Particle Absolute (HEPA) Vacuum Machines

You can use HEPA vacuums to remove the mold from the walls while ensuring no spores are left after the clean-up. Vacuuming with a HEPA machine regularly in areas with high humidity will also prevent mold growth.

Pro-Tip – Always check the label and/or instructions when using cleaners, as some may hurt certain materials or porous surfaces.

Read more: How to unclog basement floor drain

What Can You Do To Prevent Mold in a Basement?

To prevent mold from reoccurring or growing at all, you can take the following steps:

  1. Use a negative air pressure machine to filter and clean your home and basement air. The machine filters all the air out of the room using ducting. During this process, it filters all mold spores that can engender mold growth in the right conditions.
  2. Correct the moisture problem by fixing any leaks and cracks in the foundation. If your sump machine has failed, ensure it is set and running again.
  3. In areas with high humidity, install a dehumidifier and a humidity gauge to monitor the humidity levels. Always ensure that moisture stays below the 60% range at all times.
  4. Seal your foundation using materials such as a dry gypsum wall and a primer. That way, any rise in surface water due to flash floods doesn’t find its way into your foundations and, subsequently, your home.
  5. Purchase a mold inhibitor and mix with the paint, which you will use to paint the walls of your home and basement.
  6. Check to ensure that your gutters aren’t clogged, and all water is deposited far away from your home. Also, get your gardener to ensure that the area surrounding your basement slopes away from the foundations of your home.

Frequently Asked Questions

Is mold in the basement dangerous?

Yes. Mold can eat through your walls and threaten the structural integrity of your home. It also poses health risks such as allergic reactions when inhaled or touched.

Can mold grow on concrete basement walls?

Yes. Mold needs oxygen, water, and a food source to grow. Concrete walls, floors, and ceilings of dark basements are all places mold loves to grow. Even a tiny patch of standing water on concrete can lead to mold.

How expensive is basement mold removal?

The price ranges. It can be just a few dollars if you clean it yourself, up to several thousand if you have a severe infestation. Ask All Dry USA for a free quote now.

Call in the Pros to Deal with Your Mold Outbreak

While you can remove mold infestations yourself sometimes, it is wise to call in a professional and experienced remediation company if the mold outbreak displays the following characteristics:

  • The breakout is due to contaminated water
  • It covers an area greater than 10 square meters
  • It is within your HVAC systems
  • It has seeped into parts of your foundation that you can’t access
  • It keeps on coming back even after you have scrubbed it off

To deal with any of these factors and prevent the risk of a future outbreak, call in an experienced mold remediation company such as All Dry USA. We will help you restore your property and ensure there is no recurrence of mold infestation.

Ben Suiskind
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