Just the right type of hardware is necessary to adequately and safely secure handicap grab bars to wood studs, wood blocking, shower and bath walls, and drywall. Solid Mount 
Hardware is a very secure installation hardware specially designed to bridge the gap between a fiberglass shower wall and the wood stud.
The fiberglass shower wall sets off the wood stud or blocking by .5 to 1.5 inches or more. Solid Mount hardware utilizes a long bolt and bracket to extend through the wall space to the stud. (Solid Mount Image from goldenhammerbath.com) For more information about installing grab bars into a fiberglass shower enclosure, visit AtlantaHomeMods.com.