When a new shower is installed, a fiberglass shower pan is often used. A fiberglass pan provides a strong, stable base for the person using the shower to stand on, but it's also plain-looking and can detract from the appearance of the shower. You can improve the appearance of the shower by laying tile over the fiberglass pan.
Fiberglass enclosure always leaves 2 foot of drywall above. For those who are not going to put a full tile shower and want to make it look a little better and make it non-maintenance this is your best option. avstile.com