In this particular case the shower tile was still intact ... What was more surprising was that cement based backer boards were available when this home was built and this green board use reflects ...

above the tub. Fill the gap between the tile and the tub with caulk. Cement backer board is used as a sub-surface for tiling, ...

If you have to install a backer board, add $2 per square foot to the cost of the tile. Other materials will cost about $90, ...