Doug asked: How do I clean mold on cement block wall and cement floor? One end of my shop is built into the side of a hill. I am in Minnesota, so the inside wall below grade is usually cold, or cool, and damp. Mold forms on the lowest two feet of the back wall, as well as the cement floor in the back corners. The walls and floor are painted. What is the best way to remove the mold? I want to clean it up so it can be repainted.
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Moisture can move through underground cement in many ways. Often there are moisture barriers in place, but they can wear out and become less effective over time. The porosity of cement blocks make it a key area for mold growth. The moisture is able to get it, but has no way of drying up, which makes the perfect landing spot for mold spores to prosper. No matter how the moisture got there to begin with, it’s important to remove the mold completely. Be prepared to put some work into it. The materials are easy – but it’s going to take plenty of elbow grease to get rid of the mold completely.
You Will Need:
- Water
- Bleach
- Bucket
- Scrub brush or sponge
- Rubber gloves
Steps to Remove the Mold:
- Bleach is a well-known killer of mold and bacteria. In this case, it’s the perfect cleaning agent to kill and remove the mold completely.
- Start by mixing 1 part bleach with 4 parts water in the bucket.
- Put on rubber gloves to protect your hands and wear old clothing as they will likely get a splash or two of bleach on them.
- Use a scrub brush or sponge, depending the surface and severity of the mold, and dip it in the bleach solution.
- Scrub the mold with the solution until it is gone.
- When all of the mold is removed, dry the area completely.
Additional Tips and Ideas
- Protect yourself when using bleach. Always wear protective rubber gloves and open any doors or windows to allow for proper ventilation.
- If you are planning to paint the area, consider applying a sealant to the area to prevent moisture from coming through again.
- There are commercial mold removers available at most hardware and home improvement stores. They are specifically designed to remove mold from concrete walls and floors.
{ 4 comments… read them below or add one }
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Very good article on cleaning up mold from cement. However, I would add that the person cleaning should also wear a respirator (just something simple from the hardware store) – you don’t want to be breathing the mold spores.
Additionally, if your mold is in the basement and you can see it, I would not run HVAC until it is cleaned up. It may spread the spores throughout the house.
Mold cleanup
I use full strength bleach in a spray bottle. Just soak the cement wall with the bleach, let is stay for an hour, then wash clean.
Need to remove STEEL black marks on concrete
This is not a mold question. We have the mold removed and painted the cement floor, unfortunately white paint got on the sand color paint, we removed it and we name have black steel marks on cement and paint. We need to be able to remove those. We have used spic and span, also a Mr Clean Eraser. Neither have hardly touched the black left behind. We need to get this repainted with the sealant paint but need the black gone first. Any suggestions?
Need to Remove Steel Black Marks from Concrete Garage Floor
I would appreciate any suggestions that anyone has on how to remove Steel Black Scratch Marks on Concrete Garage Floor, since we have moved some appliances.
If you have any procedure that will remove these marks, please send me whatever works the best.
I am trying to get the garage cleaned up, and am having trouble removing the Steel Black Scratch Marks left by moving heavy Side-By-Side Refrigerator, and Large Freezer.
Thanking you in advance,
Linda K. Carr
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