Can this be used on normal drywall to water proof a shower?

Thank you for your inquiry regarding MAPEI products! The Tile Council of North America Standards (TCNA) states that unless you are using a fiberglass re-inforced, water resistant sheetrock, the use of sheetrock in a tub or shower surround is not considered as acceptable. If you plan to use sheetrock and then roll on the Mapei Aqua Defesne, it will adhere, but please note, there is no Mapei warranty in regards to the waterproofing the sheetrock. Hope this helps, and if you would like additional assistance with your project before you begin, please call us here at Tech Support Mon-Fri from 8 am to 5:30 pm EST at 800-992-6273. Thank you! Product Advisor # 11