Designing Kitchens and Bathrooms - One-piece shower support?

I am finishing the bathroom in our basement and just installed the shower. It is a single piece fiberglass shower with a small seat built into it. I was wondering if it is necessary to put any support underneath as the floor portion of the shower isn't resting on anything. A few guys at the Home Depot said it wasn't necessary but I would like to be sure.

Following manufacturer's installation instructions is very important. Some models do require support. Check the installation instructions. Contact the manufacturer if need be.

The base should be able to support an average weight of 233 pounds. Depending on the quality of the shower you purchased, you may or may not have a unit with integrated floor support. Many manufacturers skip this step, relying on the installer to support and level units and worry about draining and weight distribution. There is a wide range of qualities and manufacturer's as well as within their individual product offerings. The better units tend to cost more. Improperly supported showers can result in fractures, cracks, leaks and construction nightmares. A good fiberglass unit comes with the support and rests level on the floor. It feels solid. A little flex in the walls is fine so they can expand and contract.

Over time the fiberglass shower floor will sag to the point it will crack and cause leaks if it does not have a support system. Lack of or improper support beneath shower units keeps the fiberglass repair people in business.

Thanks for the advise. The builder's crew brought the shower in for us before they framed the bathroom but they didn't leave the instructions or any paperwork on it (typical of our builder). The base seems very solid but based on your post I think I will add a little support to be on the safe side.

Thanks again!