Mary Lou asked: How do I clean calcium build up from concrete blocks in the basement? We had water in the basement, and there is a lot of calcium build up on the cement blocks.
When calcium deposits land on the surface of your concrete, there is a brief amount of time that they can be removed with scrubbing and water. However, once they harden, they will require the use of acid to remove. The strength of the acid will depend largely on the thickness of the deposits and the amount of time they have been present. Start with the weakest acid and work your way up to the harsher acids until the deposits are removed.
You Will Need:
- Acetic acid
- Hydrochloric acid
- Soft cloths
- Scrub brush
- Spray bottle
Steps to Remove the Deposits:
- Vinegar is a weaker acid, but effective in removing most calcium deposits.
- Moisten a cloth well with the vinegar.
- Blot the vinegar onto the deposits so they are thoroughly moistened. The vinegar can also be put in a spray bottle and sprayed onto the surface.
- Allow the vinegar to soak on the surface for a few minutes.
- Scrub with a stiff brush. If you see the calcium deposits breaking up and coming loose, you know the vinegar is working. Continue, reapplying the vinegar as needed, until the deposits are removed.
- If the vinegar is not working, it’s time to kick it up a notch. The next level of acid is acetic acid. This is the same type of acid found in vinegar, but is available in much higher strengths at hardware stores.
- Using protective gloves and eyewear, apply the acid to the surface as before.
- Allow it to soak and then scrub the surface.
- Reapply as long as the deposits are being removed.
- If the acetic acid does not remove the deposits, as is possible with very old deposits, a strong acid will be required. Hydrochloric acid will remove the deposits, and requires safety precautions to avoid harm to skin. Wear protective eyewear and gloves.
- Carefully apply the acid to the deposits.
- Scrub with a scrub brush.
- Once the deposits are removed, rinse the surface well to remove all of the acid.
- If desired, the acid can be neutralized with baking soda or other base.
- Rinse well with water.
- Allow the surface to dry.
Additional Tips and Advice
- To avoid tough build up in the future, clean the area regularly before the deposits have a chance to harden and thicken.
- Dispose of all acids properly to avoid damage to drainage systems.
- Follow all safety precautions on the packages of acids.