Installing fiberglass shower base with Styrofoam backer

[Lee R Batchelor]

Hi all,

As the title suggests, I'm installing a 34” x 34” shower base with a Styrofoam backing, on a concrete floor in the basement. I have the drain roughed in and it's dead on where it should be. The concrete floor is off level by about 1/4 ". I was going to pour self-leveling concrete and then set the base on it but I'm concerned about squeaks. I've heard some say that I should remove the Styrofoam and replace it with a mortar bed but that would mean putting a 2” or more, bed of mortar down.

Should I stick with my original plan of using self-leveling concrete and just set the tray on it OR should I leave the Styrofoam on and set the tray in a thin layer of mortar instead? Thanks.

 

[Jeff H Young]

id probebly put a 1/4 inch shim down on the one end , and some rowes of mortar but with space for it to squish lay a sheet of plastic over or even over and underneath if subfloor is wood then set pan leave styrofoam in place. you could remove it but I never have and see no need

 

[Sponsor]

 

[Lee R Batchelor]

Thanks, Jeff. Would your solution work the same on a concrete floor? Use rows of mortar for the Styrofoam to rest on. In other words, lay the pan like a giant brick. It's low on the curved front by 1/4 inch, so add about 3/4 inch rows of mortar about 2 inches apart and tap/wiggle the base until it's level all around. Sound right?

My only concern is, the gaps between the rows may not have enough mortar for full support and the pan may flex a bit. Thoughts?

 

[Jeff H Young]

Sure Id have no issue with a slab floor . i think your plan with rows works I think itll be solid

 

[Lee R Batchelor]

Thanks, Jeff! I'll post back when I get it mounted.