I am installing a shower stall in the basement. All the plumbing is done but the plastic base of the shower stall floor sqeaks. The floor where the drain was installed is mounded up so I built a base of 2x4's around the shower base to level it up and make it soild but now when you step in the base even though the base is solid it squeaks when you stand in the center. I am really confused? Help

It's a bit late to be hearing this but you installed the shower base incorrectly. Fiber glass and acrylic showers need to be set in a bed of modified thinset just like setting floor tiles. I usually stick about 24 tennis ball sized globs under the pan before setting. Any chance you can uninstall? If not I do have a suggestion but it's a long shot so let me know about the uninstall first.

I can uninstall and get the thin set. Any particular brand? Also do I spread out the thin set evenly or do I place balls around underneath in some way. I have never done this so any help would be appreciated. Thanks
Jake

You may use thin set or cement or just plain mortar. Puddle it up so it supports the shower base especially around the drain area and then let it set up and cure before you step back in. Good luck, Tom

Just like was said above: remove the pan, mix mortar mix, and set pan into it. Put heavy object on the pan and leave it there until the mix dries. ( 1-2 days). You should have done to begin with...

The brand is not that important, you are just creating a firm base for the pan. I like modified thinset because it is a bit pasty and clings really well. Like I said, I make balls or globs of the stuff and stick every 3-4 inches all over the underside of the pan, nearest the drain is most important.

A BIG thank you to all. The way I installed it I can get it out fairly easily so I think I am good to go. Again thanks much I had no idea I had to put the thin set om first. You have been a big help!

One thing to remember is to not walk in the shower fro several days after you set your mortar. It needs to set up, the can will tell you setting time.