Thread: white crystallized crawl space substance

Hello all

We are home owners in Ontario and while gutting an addition to our home (due to mold in walls) we discovered a very thick white substance in the crawl space underneath where the laundry used to be. It was a section of complete snow white, thick substance. It almost appeared to be thick frost (pointy, rough) like you would find in a freezer and looked like we could have scraped it with our cars snow scraper!! Has anyone seen this before and do you have any idea if it is a type of mold or extensive wood rot or what ???? Very concerned.

Thank you
Signed
concerned Ontario Home Owner

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Efflorescence: Cause and Control

Originally Posted by Heather Garrett

Hello all

We are home owners in Ontario and while gutting an addition to our home (due to mold in walls) we discovered a very thick white substance in the crawl space underneath where the laundry used to be. It was a section of complete snow white, thick substance. It almost appeared to be thick frost (pointy, rough) like you would find in a freezer and looked like we could have scraped it with our cars snow scraper!! Has anyone seen this before and do you have any idea if it is a type of mold or extensive wood rot or what ???? Very concerned.

Thank you
Signed
concerned Ontario Home Owner

Hi Heather,

A photo would help.

Is this on the foundation wall or the soil/slab?

Good Morning all

Thank you for your replies. I am 99.9 % certain that we are dealing with mineral efflorescence due to the first thread that was sent to me. http://www.masonryinstitute.org/pdf/612.pdf The very first photo on this link was EXACTLY the same as what we saw in the crawl space. We are doing a complete gutt of the area (walls, ceilings, floors, insulation) right back to the outside framing. This is not part of the actual "living" space so we can leave this area gutted until the spring at which time we need to put a block foundation for the walls to be rebuilt on. I was going to see if I could find some type of industrial hepa vacuum to clean up the residue (dust, smaller drywall chunks) etc and then spray ALL of the areas with a solution of 10/1 borax and water, allow to dry using dehumidifier with hepa filter and fans and then paint every square inch with kilz primer. I am hoping this will at least get us into a more healthy situation where we can leave this area blocked off for the winter and use the rest of the house until we can begin reconstruction in the spring.