Hello, I've recently completed building and tiling a custom shower, ready now to grout, and have a 1/2" gap between the shower wall and floor tiles and am wondering whether to grout or silicone the joint? Beneath the tiles is a 4" mortar base and the walls have 1/2" Hardibacker behind the tiles. Any suggestions?

I hope you have 1/2 joints between tiles. Every one does it different. I prefer to butt all corners then grout. If it cracks then there is movement and i caulk it. 1/2 inch is a lot to caulk-id grout it

Thanks for the advice Rob. Unfortunately the shower floor ended up being 1/4" lower than I planned and based my wall tile placement on. I have 3/16" spacing between the wall tiles. Next time maybe I'll put the floor tile down first? Thanks again!