I need to do something about the tiles in our bathroom. They need to be replaced. I would like to put a 3 or 5 piece tub enclosure in instead of the tile, but we have a window in the top middle of the wall. I'm sure my husband could install the enclosure, but he is not sure about to do with the window. We would have to cut out for the window, but what do we do to make sure it stays dry underneath?? Should we use caulk, or is there something like corner molding we could use?? Or would it just be better to just re-tile?? We have to replace the backer board no matter which way we go. Thank you for any suggestion you can provide.