New Surface

To properly repair cracks in fiberglass tubs and showers, it’s best to understand how they are manufactured. They are made in a mold, First thing sprayed in is the finish which is a thin coating of colored gelcoat. Next is chopped fiberglass and resin from a chopper gun. The thickest part is the floor area which varies from approximately 3/32″ to about 3/16″ inch thick. Next to give it support, strength and rigidity strips of 5/8″ to 3/4″ pressed board are laid out in the wet fiberglass. Behind that, they spray a thin coat of the fiberglass for 2 reasons; first as a moisture barrier and so the particle board doesn’t show.

These units fail when the floor is overloaded or it gets moisture into the particle board. Either way it allows the floor to flex (move) and the fiberglass tears or cracks. Once this happens the particle board get wet and it’s pretty much over with. If yours has a crack stand at a the crack and put your weight on it, it will flex or feel spongy. what this means is the boards are either broken loose or it is wet. Either way its strength is gone.