I have this little situation in my garage. This is right under a back door that goes out to our back deck that has leaked some over the last couple years. I guess water has gotten through the flooring and caused this in the garage. Sorry the pictures aren't better, but with the rippling on the surface, it looks almost like a mushroom in texture. I haven't touched it but I did knock off a piece that was growing along the edge of the garage door framing down below and it knocks apart about like a mushroom. Can I just trim this stuff off with something and then bleach it, or do I need to get some type of fungicide? Or is it a mold I'm dealing with? Is that the same thing? Forgive my ignorance. Thanks.
Pat