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Mold in Basement

Hello - There is mold growing in my basement on all of the walls and some of the floor.  It is extremely damp and smells.  It looks like a long term fix would be to fix the basement completely and put new concrete, as the floor is always damp, maybe from condensation?  In the meantime, how can I fix the mold problem so that new mold doesn't grow and the smell is eliminated? Thanks in advance for any tips!

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Posted 2011-06-20T14:32:39+0000  by JAlex910 JAlex910

Hey Babybird!


Thanks for your question, and welcome to the community!


Lime is an excellent way of getting rid of odors and funny smells. At the Home Depot, we sell 2 types of lime, pelletized and powdered, and I would recommend for you to get the powered version. Below is a picture that we sell at my store...



If this bag is a bit too much for you, other home centers sell smaller containers of it. First off though, make sure the mold/mildew problem is corrected. As I stated in this post above yours, bleach will kill what you see: the mildew stains but not all the mold spores themselves. Even if you got the smell down with lime, the mold/mildew problem can rear it's ugly head again. Make sure you take a look at some of the cleaning solutions and steps in my posts above to make sure the mildew/mold does not come back. If it does, you'll be going through a continuous cycle of cleaning and putting down the lime; a neverending battle if you don't take the proper steps.


With that said, lime is a great way of getting the odor out of your basement right now. To use the powered stuff in the picture above, simply sprinkle a liberal amount of lime powder, typically a 1/2 a cup per square foot, on the source of the odor. Then put down a smaller amount of the powder, around one cup per 10 square feet, around the sources of the odor in a large circle. You would repeat this, if necessary, every few weeks until the smell goes away. 


Hope this helps you out,



Best Answer

Posted 2011-06-27T15:08:42+0000  by Joseph_HD_ATL

Go to Home Depot and buy you a dehumidifier and plug it in. If you do not have a sump pump you can install a drain hose to your sewer and let it run at about 50 and it will take the moister out of the area then you can use a litle lysol on the walls and floor to kill the mold that is there and all is well. 

Posted 2011-06-20T16:16:12+0000  by dee2

Hey JAlex910,


Thanks for joining the community!


Great question you asked about mildew, and the great news is that you have several ways of stopping it and preventing future growth down there as well.


Mold/mildew need 3 ingredients to grow: a source of moisture, organic material and a dark temperature space with little airflow. To get rid of mold completely, you'll need to get rid of 1 of those 3 things.


Many wall and floor structures in today's homes make a perfect place for growth and have plenty of organic material present for food.. The surface mold you see may be the result of a colony, which has established itself behind the walls, infesting your unprotected walls. Even if the walls and floor are concrete, it still is a breeding ground for mold spores to be present. So, with that said,  let's grab a mold/mildew killer&inhibitor product to get you on the right track for fixing the mold problem.


If the problem is very bad, with the musty smell as you said, the first step I would take would be to grab a mold fogger that has mildew inhibitors in it. We rent them out in our Tool Rental department and all of the customers I have rented them out to say they work great.

mold fogger.JPG

The great thing about Concrobium, the product that you put in the mold fogger, is that is also comes in a easy-to-use-around-the-house spray bottle as well....



You've noticed I've mentioned Concrobium and not using a bleach cleaning solution. Reason why is that products like Concrobium kill the spores and the airborne particles as well. Bleach works as a disinfectant and only gets rid of the mildew stains, but not the spores that cause it. 


We also have another item that's fairly new in our cleaning aisle, it's kinda cool when you see what it's made of. It's active ingredient, Chitosan is made from crab shells! Don't worry though, it doesn't smell like a fish market when you spray it, and it works great as well.

Clear Shell Zep.JPG


Now that you have the mold/mildew removed, I would say getting the moisture out of there would be a big next step. You can even paint the walls using a masonry waterproofing material called Drylok.  It paints on and stops water from coming back into your basement. Most moisture issues on concrete basement floors stem from possible moisture coming from the foundation walls, then seeping into the floor. Stopping it with Drylok is key.


Yet another way to get moisture out as well is investing in a dehumidifier for your basement. dehumidifier.JPG


We have had this question come up on our community before, to see some more threads, you can see them here and here



Again, by cleaning the mildew and attacking where the source of the moisture is coming from, you should be on your way to getting rid of the unwanted mold growth, smell, and dampness down there.


Let us know if we can assist you further,


Posted 2011-06-20T16:38:04+0000  by Joseph_HD_ATL

Hello - Thank you for your response! I have a few additional questions. 


First, how do I know when the mold is gone? Are there a certain number of times I need to fog or spray the concrobium? Or will it visually go away? What I am seeing in the basement is black and white patches of bumpy material. 


 Also, when I use the fogger I am assuming that I have to remove everything from my basement? Or can I leave everything in place and just cover it? I couldnt find pricing on the website for the rental of the fogger... any idea how much that cost?


Last, when i use the paint to seal the concrete, do I just paint over the broken surfaces in the mall? It looks like the mold is growing from behind the wall but there are patches and holes that it is coming out of.

Posted 2011-06-22T12:41:25+0000  by JAlex910



To find out for sure if the mold is gone after using what we talked about in the post above, use a mold test kit--it is the only sure-fire way to find out whether or not certain areas of your basement has mold. Below is a picture of it.

mold test kit.JPG


As for using the Concrobium fogger, there are a lot do's and don'ts regarding usage. Great questions that you asked on it, and I think you can find your answers as well as additional information on the online instructionn manual, the link to it can be found here 


As for the wall, is the mold growth on drywall or masonry or another substance? Using a paint over a concrete surface will vary from the materials to use on a gypsum drywall. Let us know on here and we can get you squared away for getting rid of the mold/mildew in there once and for all.


Keep us updated!


Posted 2011-06-25T14:42:51+0000  by Joseph_HD_ATL

I washed down the drywall with bleach water. Will lime get rid of theodor in the basement?


Posted 2011-06-26T21:09:21+0000  by Babybird

So in your response to Babybird, even though we treated & cleaned the concrete with a clorox mixture we should still use the Concrobium as you instructed to assure there will not be regrowth?  Then coat the concrete with the Drylok Masonry Waterproofer. (The source of my mold was created on top and under a spot of vinyl flooring when it became wet from rain coming into the door opening and not being properly dried. That vinyl was removed, the area treated with clorox/water mixture and we will not be using vinyl flooring any longer.)

Posted 2012-07-06T19:36:56+0000  by LizardE

Hello LizardE.  Welcome to the Community!


It sounds to me that your situation is somewhat different than Babybird has.  In essence you are saying that the area conducive to growing mold has now been changed so that it likely won't anymore.  If this door area remains dry, then I think you have solved any mold problems there.  The source of dampness is through the doorway, not coming up from the floor, or being embedded in drywall.


It will do no harm to spray the now exposed concrete floor with Concrobium, but I suspect that you really don't even have to do that.  I hope this makes sense.





Posted 2012-07-06T21:00:16+0000  by Chris_HD_CHI

Great!  I think I will still spray the Concrobium just to be safe.  Would you still suggest the Drylok Masonry Waterproofer?  We use the area for storage so we are down there often - for long periods at a time since we have extra entertainment set up down there too.

Posted 2012-07-06T21:05:56+0000  by LizardE

Thanks for the quick response.


No, the Drylock product is not a floor paint.  Besides, where is the water coming from?  It's not up through the floor, but tracked on to the floor from above.  Keep the floor by the door mopped up and clean when it rains so it can dry out, and mold there should not be a problem.  I would focus on how to keep water from coming in the doorway in the first place.





Posted 2012-07-06T21:11:18+0000  by Chris_HD_CHI
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