Hi:

I removed my bathroom walls (around tub) to stud then insulated/ vapour barrier and screwed cement board to the studs. In the process of cutting the cb and installing to walls the gaps in the corners (ceiling to wall corner; wall to wall corner) are anywhere from ¼ to almost 1 inch wide (thanks to my rookie cutting abilities). What should I use to fill these gaps or will this even be a problem when it comes to adhering the tile?

Thank you.

Anything 1/4" or less prefill with thinset and then apply your Alkali-Resistant mesh tape and thinset.

Over 1/4" you may need to replace the board if it is not fully supported and securely fastened to a stud. Otherwise, prefill,thinset and mesh tape.