I have a screened in porch with a concrete floor and want to put down ceramic tiles. The floor was painted and I am currently removing the paint. How do I get paint residue clean enough to hold the adhesive? I will be using 6"or 8" X 24" Tiles. Porch is 10' X 24'. There will be some dampness . Can ceramic tile and grout be sealed from dampness? Thank you for your time and efforts to help me.

I've removed the Sheet Vinyl flooring that's been in the kitchen for 30 years with a heat gun. Got all the glue off the 1/4" underlayment which is on top of the 3/4" subfloor. The underlayment is in good shape and I got all the glue off. It is dead level and the seams are tight. I want to lay some porcelain tiles 12" X 18" and am hoping I can get away with what I have down. I had thought about removing the underlayment, but its glued big time to the subfloor and stapled. I would appreciate if someone would advise if it is ok to move forward and if there is any prep steps I need to do 1st if I can go this route? Thanks in advance