Many homeowners incorporate a bathtub surround into their overall bathroom design. Three-piece bathtub surrounds, usually made from acrylic or fiberglass, eliminate the need for wall tiles in a bathtub area. Bathtub surrounds are low-maintenance; installation is usually much faster than tile installation. If the back wall of your three-piece bathtub surround won't stick to your drywall, there are several ways you can ensure proper adhesion.
Expose Adhesives to Air
Apply the glue or adhesives to your drywall according to the directions on your three-piece tub surround manual. According to Lowe's, you must pay special attention to any instructions that require you to expose the spread-on glue to air before you affix the tub surround panels. If adhesives are not given adequate time to set up, the bond between the tub surround panel and the drywall won't be as strong. As a result, your back wall may not stick to your tub surround.
Chisel Off Protruding Studs
Chisel back warped, protruding or out-of-plumb studs on your back wall. Use a sander or a hammer to get all of your wall studs flush with the drywall. If the drywall is damaged or the protruding studs are not easily leveled, install cement backboard over your drywall before installing the three-piece tub surround. Keep your tub surround panels flat and flush along the rim of your tub. A tub surround won't adhere properly to walls that are lumpy and nonuniform.
Set the Back Panel First
Install the back panel of your three-piece tub surround before you install the side panels. The Family Handyman website suggests holding the back wall of your tub surround in place with a small nail above the top flange. Determine if the back wall of the tub surround aligns within an eighth of an inch of the bathtub. If not, reset the back wall and check the bathtub to make sure they are level. The back wall of your bathtub surround won't stick to your drywall if it overlaps your bathtub.
Anchor with Fasteners
Anchor the back panel of your tub surround to your wall studs with fasteners, specified by the manufacturer. Avoid using household nails and screws that may not adequately secure the tub surround to the back wall. Family Handyman recommends predrilling holes in your studs before driving the fasteners through the surround. You may need to add shims, small pieces of triangular wood, to fill gaps and keep the tub surround straight and flush against the back wall. Weak fasteners that do not meet manufacturer specifications can cause a tub surround to pull away from the back wall.