Dave... bring the green board down to the top of the base... actually butt the board right down on top of the base WITHOUT overlapping the edge.

Then you will fill the VOID left between the board and the base with a thinset mortar which helps to reduce wicking in the future.

If you bring green board in so it overlaps the base edge it will cause a bow in the bottom of the walls you will be installing soon.

Other choice is to fur out walls a 1/2" and then can overlap base, but you will still keep it at least a 1/4" off the base and fill with thinset mortar, etc...

I usually just butt down on top and fill joint... this also effectively LOCKS the base in place all around perimeter edges! Base will never move!

Good luck on the cutter... plumbing supply will have it or I'm mailing one to you on Monday afternoon... ;)

Talk later...

MARK

Mark, the base was made about 3/4" smaller than the actual space so I filled in between the base and the stud framing with the mortar. It should never move. The base has about a 3/8" lip all the way around. I thought it would have like an inch or so. That way the walls would set down on the lip then I could caulk the joint. I've never seen a shower where the walls stuck out further than the lip around the base. I need to find something like 1/4" thick to put on the walls before the marble walls. Either that or I could just put the marble walls against shims on the framing.
Any thoughts?
Dave

Put the 1/2" green board on the wall as I suggested earlier.. butting down on top of the 3/8" lip... then fill the void between base and cement board. That will pull walls beyond lip of base... then you can install cultured-marble wall without it bowing out.

PS..with cultured marble walls I think you are better off with a mold-resistant green board....but installed as above.

I edited my above post to reflect that as well.

I'm getting confused now. Here's a drawing of what I'm working with.

That shower pan should sit wall-to-wall. I think you should build-up that 3/8" gap between framing and shower pan. Also, green board may not be sufficient for marble wall tile installation. You should use backing board instead, or float it.

Milo is right about cement board if this was a marble stone wall... but this is a cultured-marble wall panel and manufacturer of these walls recommend green board because you will be using an adhesive to bond wall panel... not thinset.

I also agree with Milo in that you should fur those walls out the required amount so that base meets stud... the entire wall. Then you add the 1/2" wall-board which should leave you beyond the lip of the shower base... fill void between base and wall-board. Then install wall-panels as required using appropriate adhesive and add silicone or mildew-resistant caulking between base and cultured-marble panels.

Hope that made more sense.

MARK

Ooops... thanks for clearing this out for me, Mark. I was under impression that "cultured marble" is a culture marble wall tile. You are correct. Green board is just fine.

Only one point from my experience, if I may: I would not use Liquid Nails type adhesive. It is dark brown and believe it or not - you will see the bead of caulking through the wall panel after installation.

So I think I get it now. Fur the walls out to even with the pan, install greenboard which will then overhang the edge of the pan by 1/8", install cultured marble walls on greenboard but setting all the way down on the shower base. Is this correct? Also, Mark, you said to use silicone as adhesive for the wall panels right?

I used a white mortar because of the same reason. I didn't want to be able to see the mortar through the marble.

Yes.. silicone is best here! Milo is right again... Silicone won't bleed through walls, but set wall panel so it is 1/8" off the base (use shims temporarily). Then pull the shims when all is dry and apply the final silicone bead so it sets deep under the panel.

Your pic. Is correct!

Good luck.

BTW, I got the inside pipe cutter today so don't worry about sending me one,, ;)

I would have... Just so you know!

Keep 'em coming... :)

Mark

Crud, now I guess I'll have to move the shower valve out too.

Crud is right...

Good that YOU caught that now... although some manufacturers make extension kits for just this situation...

What manufacturer made your valve?

Ummmm, it's a Price Pfister shower valve. It's not too hard to move though. I need to re-center it anyway.

That and I have to figure out how to transition from the regular drywall area to where the shower walls will start.

If I understood you...

I would just fir out the rest of the wall(s) so that there is no transition... just need to rip some firring strips and tack in place until drywalled... then drywall/greenboard line up without transition and walls look smooth!

Let me know if I misunderstood...

Well, I already have drywall on the rest of the room. I guess I can pull it down and move it all out or at least slowly taper the firring strips up to the shower. I might see if the guy from the marble place has any different ideas. He has to come out and measure for the walls anyway.

I don't see why he couldn't cut a border that is say 2" wide and 3/4" deep... then you can butt your walls up to the border and transition should look very smooth!

Just an idea... ;)

Yes, that sounds like a good idea. I'll recommend that to him.