I am trying to extend this penny tile floor. The existing penny tile floor is concrete + tile + penny tile on top. The new addition I have added is osb+plywood+cement board (as pictured on top).
I would like the bridge the gap between the cement board and existing addition.
My current plan is to fill the gap with tile thinset and cover with cement board tape. Not sure if this is the right way to go.
As far as the edge cracks go in the cement board picture, I am going to replace the cement board and drill pilot holes for the screws. I'm a beginner and luckily have more cement board! Oops.

