I built a shower base from 304 brushed 14ga stainless. It is 48x96. It has a cross brake to channel water to the center drain and 6 inch sidewalls. Do I need mortar or something else undernieth so its not spongy when walked on?

Absolutely. You will need mixture of light weight concrete or topping mix under the pan. ( that's what we use - but there is number of mixtures you could use ). With this mixture present, pan will feel solid to touch, will not buckle when stepped on, and water will not be audible when falling onto unsupported flat metal base.

I would love to see a photo of this pan. Do you think you could post one ? Thanks..

Absolutely. You will need mixture of light weight concrete or topping mix under the pan. ( that's what we use - but there is number of mixtures you could use ). With this mixture present, pan will feel solid to touch, will not buckle when stepped on, and water will not be audible when falling on unsupported flat metal base.

I would love to see a photo of this pan. Do you think you could post one ? Thanks..

Thanks, I was assuming so. Never thought about the noise though, good point. We cut the hole for the drain today, and welded a recessed plate undernieth so the drain will be flush. I will post a picture when its all done, but that may be a few months yet. The shower is going in a cabin were building. Hope to be done by christmas.

Make sure you flange downward the drain opening so you don't create high point. We'll wait for the photo...

Absolutely. You will need mixture of light weight concrete or topping mix under the pan. ( that's what we use - but there is number of mixtures you could use ). With this mixture present, pan will feel solid to touch, will not buckle when stepped on, and water will not be audible when falling on unsupported flat metal base.

I would love to see a photo of this pan. Do you think you could post one ? Thanks..

Thanks, I was assuming so. Never thought about the noise though, good point. We cut the hole for the drain today, and welded a recessed plate undernieth so the drain will be flush. I will post a picture when its all done, but that may be a few months yet. The shower is going in a cabin were building. Hope to be done by christmas.

I almost forgot, should I put in a gob of mix and cram the base into that, or shoul I try to build a sloping bed first? How do leave a feedback on here. Thanks

First dry fit the pan and drain. If all fits OK, than: You mix 90lbs bag of light weight mix ( you have oversized pan: you will probably need 2 - 90lbs bags) . Mix it wet. Too dry will be problem. Mixture has to start slowly spreading on its own when put in on pile. Put it on each side of drain in 2 large separate blobs. Take the pan, put it over it, push it down as much as you can with your hands and than step inside until you fee pan cannot go any further. Don't over push. Go gently about it. Now connect drain and you should be set...