Shower floor repair

Originally Posted by pinkertonpv

The Master bath shower in a 20 yr old house I recently purchased had a major water leak. The shower is 4 ft by 8 ft and is lined with what appears to be cultured marble including the floor.

The floor had several cracks that had been caulked to stop the leak. After checking the floor from the crawl space and seeing the rotted wood, I removed the floor with hammer and chisel/crowbar. Underneath the floor was about 2 1/2 inch thick circles of what appeared to be Quickrete.

After removing this I was down to the rotted sub-floor. There was no pan liner, membrane or any thing else between the concrete and sub-floor. I removed the rotted portion.

Along the walls at the original floor level are one inch thick trim pieces of the cultured marble that I left in place. So the sub-floor is 2 3/4 in below the trim. There is considerable rotted wood under the wall with the shower door; however, all other walls and wood appear to be solid. I will replace all rotted wood from the crawl space beneath the floor.

My question is how to replace the floor. Videos on the web show in new construction installing sub-floor, tar-paper, pre-pan mix w/slope to drain, liner and pan w/slope to drain and finally tile.

Cement board is used on the walls. I don't want to remove the cultured marble on the walls but will probably have to remove the bottom 6 inches of the wall along with the trim. Will probably have to remove the C/M at the door to insure pan and liner are correctly installed.

Should I replace the bottom 6 inches with cement board over the membrane liner? Then same tile on floor goes up backer board? Can I tile over the cultured marble?

Do I need to attach cement board or some other backer board over the C/M first before the tile? Or do I need to remove the C/M if I want to add tile on walls? This may be necessary for the shower door wall if the rotted wood goes up the studs. Haven't seen that yet.
Any comments are welcome.