Mold Removal + Concrete

As you know, water or moisture can cause the most damage to buildings. Whether from a leaking roof or something as disastrous as a flood, water can be considered the root of all building problems. Water and moisture often lead to mold growth, sometimes in visible locations, but also in unseen locales throughout your building. One of the most important tasks after water damage is to remove all items from the building that have been touched by the water: sheetrock, insulation, rugs, furniture, everything.

Following the removal of flood water and then the removal of mud, we removed all items from the basement. It took days to remove all of the mud and over one week to get the basement to where it looked dry.  We washed our belongings, sanitized them, and have yet to return anything to the basement.

Now we are dealing with mold issues on the concrete basement walls, generally in locations at or below where the muddy water settled for a few hours. Originally we thought bleach would do the job, but it’s been a few rounds of bleach (one of those rounds was undiluted bleach!) and the white, fuzzy mold on the walls keeps appearing.

We have heard conflicting information, too. First, we heard that bleach would remove the mold and that the other products were all marketing. Then we heard otherwise. So, like a good homeowner and preservationist, I turned to my books and online resources. I learned that the chemicals in bleach are inactivated by organic compounds.

Darn. But, that explains why the white fuzzy mold keeps returning.

The concrete walls in our basement are certainly not of the non-porous variety. They are 83 years old and quite porous. In a handful of locations, I can see the aggregate that composes the concrete. It is not like today’s concrete, that’s for sure. Thus, the dirt and whatever else has migrated into my concrete walls is deactivating the bleach, and allowing the mold to grow.

We’re stumped.

All of the literature I have read, whether it’s from the National Trust or a university or any random website, simply talks about the importance of mold removal and safety precautions. The articles discuss the importance of drying out the basement and air circulation and a dehumidifier, of course. But, I need to know what to use in order to remove the mold and keep it away. I have yet to find a resource that mentions specific products proven to remove mold from concrete.

Can you offer a suggestion? What should we do?

I think our next step is to suit up and scrub the walls. But, with what? I’ll keep looking, but if you have an idea or even better – a proven solution – I would love to know.

Thank you!