Al, we need more info to diagnose. How old is the house, the shower? Does it have tiles or molded sides? Can you get matching tile or do you have some left from the original job? Is it only the short wall where the faucets and shower head are located, the other short wall, or the long wall? By the way, most modern showers don't have drywall under the tile, they have cement board. Installation techniques are similar but the products used are different. Do you know for sure which you have?