I recently paid a tile installer and plumber to repalce my tile shower. It originally appeared that they had done a great job (tile, thinset, cement board and sheetrock), but then I began smelling mildew. I have access to see the outside of the shower wall. The installer placed the sheetrock (green board) inside of the shower liner and down to the bottom of the liner. The sheetrock is wicking up moisture and causing mildew (Houston, TX).
How can I prove that this is an improper installation technique and that he needs to rebuild the shower with the sheet rock outside of the liner where it cannot wick up moisture?
Is there a code or design standard that I can quote?