Est. 1998 — 27 years of woodworking knowledge
After Flood Issue
Stuart Johnson
Our house flooded Saturday morning. We had the carpet ripped out and fans blowing by noon. The slab seemed to dry very rapidly but now we are getting some sort of "growth" in some of the slab cracks. I have no idea what this is or what needs to be done prior to having some new flooring laid.
Re: After Flood Issue
GarthinSanDiego
Looks like eforvescence, salts coming out of the wet concrete. Just vacuum when dry.
Re: After Flood Issue
Kevin French
You can hit it with a some vinegar if your worried
Close...
Jason Roehl in Lafayette, IN
That would be "efflorescence".
"Effervescence" is gas coming out of an aqueous solution--the "fizz" in soda.
Jason
Re: Close...
Barry Irby
Jason nailed it. Its chemical "flowering". Metallic salts coming out of the concrete with the water and "blooming" on the surface. One way to look at it, it's proof the slab is drying. It's probably calcium chloride. In the short term it's harmless to the slab and you. Vac it up and or damp mop it with a mop dry enough to not soak water into the slab.
chemistry
Bill Tindall, E.Tn.
The water dissolved some of the calcium that was in the concrete. As the solution came to the surface it reacted with carbon dioxide in the air to make calcium carbonate which came out of solution to make this solid which precipitated from the calcium rich solution. This phenomena is common when water permeates mortar because mortar is permeable to water. Well made concrete is greatly less permeable to water. Unsure why you are seeing it.
Just wash it off. Do not recommend vinegar treatment.
While the concrete may appear dry it could take days for the water that permeated the concrete to diffuse back out. Lay a piece of plastic on a test area and see if it is damp the next day underneath.
Re: After Flood Issue .. Thanks
Stuart Johnson
Thanks for the quick answers. I can now assure my wife that it isn't the first stage of black mold and she doesn't need to drench the slab with bleach.
mold
Bill Tindall, E.Tn.
It is not likely mold will grow on concrete. Concrete and mortar tend to be basic and mold prefers an acidic environment. In fact some (all?) mold makes acid to improve its living conditions.
There may be other areas that get bleached. Remove your steel tools from this environment. The volatile chlorine will find the steel and initiate corrosion that is hard to stop.
did the sheetrock get wet?
Ian Neuhaus
if it did that's the most likely source of mold
Re: did the sheetrock get wet?
Stuart Johnson
No, the sheetrock is fine. Compared to many others we just got tamp. The carpet and padding were ruined but were ripped out before it could get up the walls. This is our third flooding so we knew to pull it way as fast as we could. Still a mess.