No offense, but that is a handful of bad ideas.
The tiles definitely need to be set in thinset mortar. Preferably dry mix thinset as opposed to the pre-mixed stuff. Using silicone to put shower/bath tiles in place is something that a bad handyman would do to get done with the job in a hurry, and it is a poor practice.
Although I suppose you might be able to get away with just silicone between the tiles in lieu of grout, I feel it is a very bad idea. It'll be a maintenance nightmare in a couple years.
Be sure that you don't just apply the tile straight to the backerboard without doing a couple things first.
1) You must use thinset and mesh tape to mud and tape the seams and corners of the backerboard. Otherwise you're almost guaranteed the tiles will crack.
2) You must waterproof the backerboard before tiling. Redguard is the least expensive option. Kerdi is the best option and costs considerably more.
The tiles definitely need to be set in thinset mortar. Preferably dry mix thinset as opposed to the pre-mixed stuff. Using silicone to put shower/bath tiles in place is something that a bad handyman would do to get done with the job in a hurry, and it is a poor practice.
Although I suppose you might be able to get away with just silicone between the tiles in lieu of grout, I feel it is a very bad idea. It'll be a maintenance nightmare in a couple years.
Be sure that you don't just apply the tile straight to the backerboard without doing a couple things first.
1) You must use thinset and mesh tape to mud and tape the seams and corners of the backerboard. Otherwise you're almost guaranteed the tiles will crack.
2) You must waterproof the backerboard before tiling. Redguard is the least expensive option. Kerdi is the best option and costs considerably more.
