Last Friday, we pulled up our hard wood floors because they buckled, we know we have a drainage problem and Also last Friday they starting digging the trenches for the drainage around our property. I noticed on Saturday that there is white fuzzy stuff popping up on the slab. I sprayed with bleach... didn't go away. Last night I scrubbed and used a mold killer ( I don't remember the name) and today it's back. What else can I do to get rid of this stuff so we can have a new floor put in our house. Will the moisture barrier under the floor help?

Efflorescence -- White Fluffy Crystalline Powdery Deposit on Concrete (http://www.factsfacts.com/MyHomeRepair/efflorescence.htm)

Drylock's dry powder for painting prep that's mixed with water will work too. Use adequate ventilation and personal protective equipment for working with acids. Gloves and goggles and clothing you don't care about.

What cause the white furry stuff to come on my concrete floor?