Filling gaps and cracks in bathroom concrete floor

cloudhoppa

Hello! Thanks in advance to anyone with time to help! I just wanna do it right the first time! So i'm redoing a small bathroom's walls and floors, already had the plumbing redone. The pictures here are of cracks, holes, and over 1" gaps on some walls between the concrete and studs. I've searched and searched throughout this website but haven't quite found my identical situation. I want to put ceramic tiles down, not sure what size yet. There are lots of options for concrete fillers and such, any suggestions?

I have no restrictions with time and want to spend the money to do it right. I pulled up the old ugly ceramic tiles and some of the underlying concrete just crumbled or came up.

Attached Thumbnails

     

GottaFixIt

My initial suggestion would be a polymer modified concrete after proper prep. Of course its important to find and fix the cause before patching it, though.

cloudhoppa

Should I square out the bigger holes with a chisel and then I think use concrete bonding adhesive, then the quick set concrete fill? Like is said earlier, theres a lot of options for concrete fill, I want to use whats best for a bathroom/more humid than a normal floor.