Then pull the tile and small squares of drywall out together.
Rotten wall behind bathroom enclosure.
Install an air barrier behind showers and tubs installed on exterior walls.
Fiberglass and acrylic tub and shower enclosures come with a flanged edge that attaches directly to the wall studs and the proper way to hide this flange is to install drywall over it.
If any of the wood studs appear wet and moldy you can clean them with a water bleach solution.
Leave some of the old drywall exposed where it will meet the new backerboard.
Leave a 1 8 inch gap between the bottom.
Position the cut drywall sheet on the wall.
Drop those pieces into a bucket of hot water to separate the gypsum backing from the tiles.
If you find that the wood is rotted you will need to replace it.
Any insulation that is wet or moldy will also need to be replaced.
Allow the wood and wall cavity to completely dry.
Cover the wall cavities with a rigid air barrier or other supporting material to prevent cavity insulation from sagging and to create a continuous thermal barrier.