Shower base is not sitting flat on concrete floor

[mc1984ss]

I am getting ready to install the shower base in my basement. It is a multi piece Sterling unit. The shower base has raised ribs/ gussets underneath that support it. The unit "rocks" back and forth on the floor front to back because there is a slight high spot in the concrete right by the shower drain. My plan was to file or grind down the ribs on the shower that are causing it to rock and make it sit flat. I plan on bedding it in mortar so my thought is even if I grind to much off the mortar will make up for it. I would much rather do this than grind the concrete. Let me know what you guys think, thanks in advance

 

[brownbagg]

pour a bed of wet grout, set the pan and squeege the excess out

 

[b-boy]

Personally, I'd grind the concrete as opposed to the ribs.

 

[rsanter]

I would leave the ribs and just mud it in

 

[The Cobbler]

im in the set it in mortar, grout whatever camp . level the base , let it set & good to go

 

[ericlar80]

When I installed a solid surface shower base, the instructions said to use silicone caulk. Instead of applying beads on all the ridges, you are supposed to place a pile of it every 8" or so. Let dry before walking on it.

 

[James-W]

I would put shims on the floor so the base sits level. Once the base is level silicone the shims to the floor so they don't move. When the shims are stuck to the floor so they don't move, remove the base and put down several piles of silicone caulk and them push the base down so the caulk flattens out and the base is level. Now let it dry for a day and then you can continue with the project.

 

[like2wheel]

Check for level in all directions before you do any grinding. If that spot needs to come down, I agree with your plan, as long as you still bed it in mortar.

 

[ferrari52000]

I am in the set it in mortar camp.


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[jeffmattero76]

Dry fit the base on the floor and shim it to level. Mark the top of the base on the wall studs with a pencil all around. Remove the base, mix a batch of mortar or Structolite a little wetter than usual. Dump that on the concrete, and spread it around on the footprint of the base. Install the base and tap it down until the pencil marks show. Wait 24 hours for it to set.

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[redneckcharlie]

What ever you do, do not grind the pan support on the bottom of the unit. Fiberglass and composite units have a nasty habit of developing cracks over time due to flex. Weakening the supports just increases that risk. One of the best ways to set a shower unit Is to get it in place level, then remove it and use a few cans of expandable foam as a bed, then place the pan. You only want enough foam to float the unit slightly until putting some weight in the pan to hold it in place till it sets. If you have access during rough in you can do the same procedure by placing it and pumping in foam from the sides. I’m not a fan of the composite units at all, but if a client absolutely has to have them this is how I set them. Mortar works as well, I just prefer the spray foam.

 

[LXCam]

Just bed it in mortar and call it a day.

 

[benjamintmiller]

Agree with the others -- high quality shower installations always include a mortar bed to prevent flexing when you step in the shower.

When I install a shower, I lay 6 mil poly under the mortar so the pan can be removed if needed some day.

 

[rburke65]

When I changed my shower out....multi pieces....directions said to place base in mortar and level. That’s what I did.

 

[like2wheel]

When I install a shower, I lay 6 mil poly under the mortar so the pan can be removed if needed some day.

I did that when I bed my whirlpool tub 24 years ago. Just tore it out last month & was glad I did that.

Just did the same with a shower.

 

[ard]

+6 or 7?

Bed it in mortar. Tub, shower....

 

[Jfive]

Agree with the others -- high quality shower installations always include a mortar bed to prevent flexing when you step in the shower.

When I install a shower, I lay 6 mil poly under the mortar so the pan can be removed if needed some day.[/QUOTE

This exactly. Mortor bed with plastic so you can remove if need be down the road. Un bedded shower pan will groan and creak if not bedded then someday crack and leak.

 

[PugetDude]

This exactly. Mortor bed with plastic so you can remove if need be down the road. Un bedded shower pan will groan and creak if not bedded then someday crack and leak.

+10. The mortar makes the pan feel a lot more substantial, too.

 

[hefnerconstructionlc]

As above set in the mud bed. Or at the very least spray foam. Those fiber glass pans are notorious for flexing and cracking.

 

[Falcon67]

I'd bed it in mortar - same as I did for the showers in our old house, placed on a wood floor (pier & beam). However, I'd make sure the base sat flat on the sub floor, grinding the concrete as required to get a firm lay.

 

[K'ledgeBldr]

Grout bed. No grinding or cutting of concrete or plastic/vinyl.

 

[dave*99]

You need something structurally sound to support the shower pan.
Structo-Lite non shrinking mortar.