Acrylic shower base setting bed.... [Archive] - Ceramic Tile Advice Forums - John Bridge Ceramic Tile


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05-08-2010, 09:20 AM
Installing An Americh shower base and the instructions say, " Prepare the shower base setting bed using lightweight cement, plaster, gypsum or fix-all."

What is the best material to use to provide a solid bed? Fix-all seems too likely to eventually crack, will thin set mortar work? What exactly is "lightweight cement." I am familiar with products such as Sakrete lightweight concrete but it says that it is for applications at least 2 inches thick and I don't think the bed will be more than an inch and a half at it's thickest and much thinner toward the drain. :confused:

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05-08-2010, 02:43 PM
this should help:

05-08-2010, 04:33 PM
Very useful link & I think I got the idea.

One more question for anyone; the shower base calls for a 1X2 framing ledger to be installed to the studs so that it is just underneath the edges of the shower base. The framing ledger is "not for structural support."
If it is not for structural support, what purpose does the ledger serve?

Houston Remodeler
05-09-2010, 08:59 PM
I am gonna guess there have been a few DIYers who have dropped pieces of CBU on that lip and crushed the pan. Or had the CBU weight deform the pan, causing water to set on the lip.

I should blow the dust from my crystal ball.

05-10-2010, 08:36 AM
i.e. The ledger serves to offer protection vs support....
Thanks Paul!

Tool Guy - Kg
05-10-2010, 08:58 AM
If it's underneath the edges of the shower base, you're describing a ledger that's there to help you achieve a level pan installation when setting in the thick bed of mortar.


05-10-2010, 04:55 PM
Exactly; the 1x2 ledger is to be installed underneath the edges of the shower base. The base seems to be of good quality, the installation instructions; not so good! There is an illustration showing the ledger but no mention of the proper height to install it on the studs, just a warning that it is not for support.
Since it is a single threshold, I figure that I'll just place the pan on a flat surface and temporarily support it underneath until it's level, then measure the distance from surface to the underside and mount the ledger at 1/8" above that distance since the mortar bed should raise it up a bit from it's lowest point at the drain hole.
But then again, I think I'll call Americh to see if they have a recommended height.

Houston Remodeler
05-10-2010, 05:16 PM
That sounds like a decent plan

Tool Guy - Kg
05-10-2010, 09:37 PM
The warning that the ledger is "not for structural support" is to drive home that fact that you can't get away with just the ledger for support...that the bed of mortar is mandatory. Your plan for the ledger height will work.

Have you decided on the mortar you'll be using?...just wanna make sure you're not going to use thinset. :)

05-10-2010, 10:31 PM
...Bubba, but no; no thinset.
I went and bought a 60lb bag of mortar.
Think I'm about ready to set the shower base. Just don't want to make any expensive mistakes. Thinking of putting down some building paper on top of the plywood underlayment so the moisture from the mortar doesn't transfer.
Thanks for the help.

04-02-2011, 12:23 PM
I set my acrylic shower base in a setting bed of mortar. I finished surrounding it with backer board and while standing in it, it seems sturdy with no flex or squeaks. While cleaning up around it in preparation to tile the floor, I noticed that I can move it. In fact, I could probably pull on it and slide it out.
Is this normal? I was assuming that the shower base stuck to the mortar and was held in place, or is it just there to provide support?
Obviously when I set the floor tile and finish installing the drain it will no longer move around, but I want to be sure I didn't *F*-up! :uhh:

04-02-2011, 02:51 PM
What is the model and manufacturer of the receptor? Did you follow ALL manufacturers installation instructions? Most, if not all, require the receptor to be attached to the framing, which, if done, would prevent it from being moved. Yes, the mortar is for full support, not attachment.

Post a link to the installation instructions, and post some photos of your install if you're still unsure... :)

04-02-2011, 04:01 PM
William, it'll help a lot if you'll keep all your projects on one thread, no matter how old it gets, so folks can see what you're working on and what's been previously asked and answered. We can give it a more generic title any time you'd like.

As you can see, it'll help reduce confusion and duplication, eh? :)

04-02-2011, 04:42 PM
I hear you CX. The thread was just so old....but I understand.

dhagin, Yes, followed all instructions and there is no attachment to framing.
(Checked the website manual pdf in case there was an update.
I was just shocked, and worried, when it moved as I did not expect it.
I does seem solidly supported, but when I set it down in the mortar I just assumed it was gonna "stick."

04-02-2011, 05:26 PM
Those instructions ARE lacking imo. What is common, when no other instructions contradict, is to nail/screw just above the flange. Use corrosion resistant nails/screws like galv roofing nails, stainless steel screws, etc... Don't deform or bend the flange if it's not tight to the framing, use shims in this case. Just run the nail/screw snug to the flange and stop.

I'll try to find a photo... :)

edit; Couldn't find a photo of that method, but here's another

04-02-2011, 05:49 PM
I certainly agree that the instruction manual is lacking!
(Almost every product I've bought for this remodel has had poor documentation. The double sink vanity came with what looked like a poor photocopy of a generic cabinet with some arrows and numbers randomly added.)
The way the splash flange is constructed I feel more than a little nervous drilling holes in it to set galvanized nails or to attach it with a screw so that the screw head is flush.
I think driving two small shims in between the front of the base and the surrounding framing might just do the trick to eliminate any movement.
That plus the drain install and the tile floor that will border the front of the pan should eliminate any movement..... I hope!

04-02-2011, 06:00 PM
Check the picture in the last post of mine. If you're careful, it will work fine. Caulk over the holes with 100% silicone. :)

For the first method i described, the nail/screw goes just ABOVE the flange so the nail/screw HEAD catches the top of the flange. NOT through the flange.

Either way, shim behind the flange if needed to support the force of the nail/screw and to keep the flange from deforming. :)

04-02-2011, 10:38 PM
Excellent. Thanks dhagin. The illustration was very helpful.