Our plumber installed our tray. He wanted certain materials under it and felt he would be the best to install it

Thanks millworkman and jck910. We talked to the company who is fabricating this quartz tray and they said they don't put anything (membrane or adhesives) under the tray (!) during installation - that the main thing is to keep it level. This advice seems reckless, but what do I know? Finding anyone with experience using this material in showers is tough in our area.

The solid one piece trays I've looked at don't have anything under them, except perhaps some dry mix. But that's specified by the manufacturer. Tile, of course, is completely different.

If this shower tray is built using Cambria Engineered Quartz then I would highly recommend that you install a waterproofing member underneath and extend it beyond the trays footprint. This tray will be built using individual pieces and will have a number of seams which could crack over time and therefore result in a leak.

Thanks Kitchen Abode - the tray is one piece. The walls of course will have seams.

If it is made with Cambria how can it actually be one piece if it is a tray. It may come as a single unit but that unit would be comprised of multiple pieces glued/seamed together.

Ok, got it. The tray is from Silestone. Looks to be a solid 1 piece cast unit, no seams. Would still recommend a waterproofing, seems like the right thing to do to do the best you can to protect your investment and the underlying structure.

Waterproofing would be cheap insurance in my opinion.

I'm glad you folks told me that Silestone Cambria leaks. You saved me from putting in a sink and kitchen counter tops. I won't use it if the stuff leaks.

Just refreshing this thread. The quartz shower is GREAT. One year heavy use and all is well, cleaning is so easy. I will never not have a quartz shower. Weedmeister - Silestone, Cambria and other quartz do not leak.

If I fabricated an engineered stone shower pan, it would not leak nor would any additional waterproofing be necessary.