Thank you in advance for any help you can share with me. I was called by a prospect to evaluate their travertine floor in the master bath and when I was measuring the floor I noticed this problem growing on their shower floor. This seems to be a salt (or some substance ) that is up to 3 inches wide and a 1/4 to 3/8 inch high. Can efflorescence turn into a hard mass like this considering this shower is used every day? Also, there is really not an evidence of mold growing elsewhere in the shower.
My situation is that I want to get a sharp chisel and hammer at an angle and try and break it loose, but I am worried about cracking the travertine. You can see in the photo that the mass follows the grout lines. If I use an acid it will etch out the tiles. Is this a job for me or a demo team and a tile installer?