How to Remove and Get Rid of Black Mold in Your Basement {a step-by-step guide}12 min read

How to Remove and Get Rid of Black Mold in Your Basement {a step-by-step guide}12 min read

Do you see black mold in the basement? Or traces of spongy looking grey or black deposit on walls or ceiling or floor in the basement?  Do you smell a musty odor? Well, do you notice high humidity in your basement? And want to get rid of mold in your basement….

If you feel any of the above or notice wall colors deteriorating, then the chances are you have mold in your basement.  This is of serious concern and is not a time to take things lightly when you notice any strands of fungi growth. 

This article will dive deep into the identification and cleaning the black mold.

Word of caution! Do not disturb the mold, until you have a good grasp of how to completely remove and get rid of black mold.

It’s a Serious issue – Don’t Ignore

As you may have heard molds are not just ugly looking but they cause damage to your house.  They can even cause structural damage, eventually. 

Mold due to slow water intrusion through the external wall

While this article refers to black mold as a single type, it is not so.  In fact, there are 100s of varieties of mold and that black mold may be anything from Stachybotrys, S. chlorohalonata to S. chartarum.

The mold growth can be yellow, beige, green, grey or black in color.  And there are usually many different varieties at play at any given time. 

It’s hard to identify just by color but if you are experienced at it, and based on the geographic location, you may be able to identify some of the strands easily.

In any case, the main warning here is don’t take it lightly. This is a serious issue and can cause health hazards.  So you need to act quickly and get rid of the mold quickly.

Let me clarify something. Most mold spores are not a problem. Well, if I just stop there, people will kill me. But that is the fact.

Then why is mold dangerous? It due to the mycotoxins they release. So the black or dark green mold you see is just fine as long as the spores count is limited.

However, if they go beyond the limit, you will inhale a lot of these spores. Then they release mycotoxins which in turn causes a lot of health-related issues.

Prevent – Instead of Getting Rid of Mold in Basement

Prevention is better than cure! Enough said…

Identifying, cleaning and eradicating is very very hard. Once you get them in your basement, getting rid of the black mold is a hard task.  

Humid, wet and smelling musty? then you may have a moisture problem.

In fact, depending on the size of the infestation, you need to call a mold cleaning pro, that can handle biohazards to get rid of it.  It cost a lot. How do you ask? Well, I had to call a pro 3 times before it was completely taken care of.

It’s so easy to put some preventive measures in place so you don’t get into the problem in the first place. 

There are three conditions that must be met for mold growth. Comfortable temperature, an organic medium, and moisture. It’s hard to control the first two on the list.  So we must control moisture in the basement.

Check for moisture level in the basement.  That means two things.  

  • Leaks in the basement and identifying the source of water intrusion.
  • The humidity level in the basement

Check if there is any water getting from the exterior through a cinder block.  Are there cracks in the basement walls?

Do you have leaky pipes?  Or any plumbing fixture that is constantly dripping water somewhere.

Are floors showing cracks and is it exposed to pulling in moisture from below the ground?  

Do you see traces of black patches on the wall, ceiling or floor? Or do you feel the drywall in the basement to be cold and wet?  These are all the things that you should see in your basement and try to prevent before mold growth.

Fix leaks, divert water away from the foundation and get a dehumidifier in the basement.

After identifying moisture issues in your basement, try to take necessary corrective actions.  

It’s going to be way cheaper to fix the issue and install a dehumidifier than combating the mold once it’s rampant. 

Try to move objects away from the source of the issue.  In any case, don’t put things against the wall. 

Find a way to move the air.  Moving air has less chance of mold growth than a stagnant one. Invest in an exhaust fan, but you should know what you’re trying to achieve when installing.

Avoid storing organic matter in your basement, which is just providing fungi more breeding ground. 

Mold Basics

Mold is nothing but fungi and they are found everywhere. So, when you walk the park you are inhaling and that is fine.

In fact, you need a mold to decompose all the dead organic matter (such as fallen leaves) in our environment. 

They grow in a nice temperature when it can find humidity and an organic matter to eat. They are what we call the necessary evil.

Mold in certain quantity is totally fine, however, if it exceeds a certain count it becomes toxic and is a serious concern for health.

Mold Types – How to Identify?

You will be surprised to know this fact. There are as many as 350,000 mold species, according to the Centers for Disease Control

While the common indoor molds are Cladosporium, Penicillium, Alternaria, Aspergillus, etc.

You may not be able to identify just by visually looking at the mold growth. Certified mold inspectors take a sample and send it to a lab, where the lab tech identifies the specified under a microscope and report back.

While you will be very familiar with Stachybotrys that’s just one, albeit a dangerous one.  And to add to the confusion there are more than 50 species of Stachybotrys.

So finding it out yourself is out of the question. If you still need to know the type of mold growth in your basement, you must send the sample to a lab to identify correctly.

Labs give two sets of information.  The type of fungi and the count. A competent mold inspector will take 2 samples. One inside the house and another outside the house. 

The lab then looks at each type of mold present in the basement and try to compare it with the count of mold spores in both the samples.  If there is a significantly larger number of spores inside then the lab finds it to be an issue with that specific species.

Steps to Getting Rid of Black Mold in Basement

Like I mentioned before the title might say Black mold, but you should get rid of any and all kinds of mold.  The steps are fairly straight forward and detailed below

Mold technician using a full body suit, gloves and a respirator mask

Use precaution and follow this always.  Cover your body well, use a respirator mask, goggles for eyes, gloves for hands and have a HEPA vacuum to clean.

  1. Remove all items from the basement.  All moveable object must be out and you need to have a fairly clean working space.
  2. Identify the source of moisture intrusion and try to resolve it. If it’s a leaky pipe, get a plumber and fix it.  But on the other hand, if you have the issue behind the drywall, you may want to cut remove the drywall (as in the next step), fix the problem and then move on.
  3. Access the problem.  Do not touch or disturb the mold.  Spores can be thrown into the air and will create bigger problems.
  4. Try to isolate the area that you will be working.  Use a 4mm poly sheet and use it to make a small work area.  Make sure the area is airtight and air can’t leave that room. It’s ok to suck clean air in, but not throw the air with mold spores out.
  5. If your drywall, ceiling tiles, insulation, and carpet have deeply infested mold, do not try to clean.  It’s easier, faster and safer to cut, remove and throw them. You should get a lot of construction grade black bag and should start dumping all the infested removable items in it.
  6. For very topical and surface-level mold growth in the basement, try to use a mold killer and clean it thoroughly and let it dry. ( I try to stay away from bleach as much as possible)
  7. Now you will be left with structural objects in the house such as cinder block, studs, and beams. Apply the mold killing solution on the affected area, use a wire brush and scrub it thoroughly. Remember mold can penetrate porous materials and you should soak the material such that the mold spores are killed all the way inside.
  8. Once completely cleaned, you need to let it dry fully and then apply a sealant.
  9. If you fear suspending spores in the air, you need to have a sophisticated setup. Set Up an air scrubber which will constantly clean the air while and after you are done with the mold cleaning.
  10. Maintain the correct humidity level in the basement so the problem doesn’t recur. 
  11. Wipe and clean furniture that you originally removed from the basement, before putting it back in the basement.  Anything that can be trashed must be trashed.

If the mold is extremely topical you may use bleach to get rid of it. However, remember that mold grows on the surface and it penetrates into your basement walls too.

So using bleach is going to kill the mold on the surface and doesn’t penetrate. When experts ask you to not use bleach it’s because of this and not because it can’t kill. That’s just a myth.

Disclaimer: I’m providing this article for educational purposes only. This is a sound plan but you must exercise caution and be more protective.

What to do for Mold on Basement Floors?

It’s tricky to identify. If you end up having a non-porous material on the floor you may not even notice the black mold. It will be silently living and growing underneath the flooring material.

A lot of is caused due to a leaky pipe somewhere that is dumping water.  Or due to moisture seeping up through the floor. In either case, you need to resolve the issue.

To remove black mold on floor, you first need to remove all the flooring material and trash it. Take the mold killing solution and saturate the affected area and let it soak.

Like earlier, scrub it with a wire brush and wipe the visible mold growth.  Do not scrub without using the solution. The solution is to first kill it and scrubbing is it to remove the dead ones.

Once cleaned, you may use a mix of warm water and vinegar or an ammonia-based solution or a bleach-based product to clean the floor properly.

“Warning! Never ever try to mix bleach and ammonia.  The produced fumes will be toxic.”

Rinse it with water and let it dry completely.  Use a floor heater to expedite the drying process.  Have a dehumidifier to reduce indoor humidity in the basement.

Before installing the flooring material, get a good quality underlayment which acts as a moisture barrier and lay it first. 

Then go ahead and install the flooring material. However, if you are going to install products such as vinyl tiles, you may do so.

How Much Does it Cost to Remove Mold from Basement?

First, you must decide if you are going to remove the mold yourself or call a pro to do the remediation and get rid of mold in the basement. 

Second is the product used in mold removal dictates the cost.  If you have a small area in the bathroom, then you can get away with household items such as vinegar, borax, peroxide, etc.

If it’s a DIY mold removal project with home supplies it $0. And if you buy specific hospital-grade mold remediation and sanitizing solution then you can be done with under $50.

However, if the infestation is large and you don’t know how to properly remove without causing further damage you will like to be calling a professional mold removing company.

The cost can range between $500 – $7000. This involves isolating the area, scrubbing cleaning, removing and sealing every non-removable item in the structure such as studs, beams and cinder blocks. 

And for all other removable items such as carpet and drywall, just remove and trash them.

Depending on the extent of the infestation in the basement and type of fungi you may choose to do it yourself. 

In fact, CDC recommends a maximum of 10 square footage until which homeowners can remediate mold themselves.

In any case, you should identify the source and stop the moisture problem before you finish the mold removal job.  If not, then the problem will reoccur and we can’t put a dollar figure to it and likely incur a future cost.

As always, if you liked this post, please share this post and this image on Pinterest and social media. You may just help someone in need of a better living condition.

Info graphic on Mold growth and conditions needed for mold to spread

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