Uphonor PEX Expansion Rings Getting in the Way of Shower Drywall at Elbows

[pollymath]

I plumbed my shower with PEX Expansion fittings.

I also used Uphonor PEX Expansion Drop-Ear Elbows for the Shower Outlet and Handshower Outlets.

My tile guy requested the drop-ear elbows sit out far enough that the Kerdi-Schluter Membrane Gasket would surround the NPT fitting. Thus, if either of the shower fittings leaked, they would do so within the waterproof barrier. This is Schluter's approved install method. So my tile guy is correct.

However, with the proper depth of the Drop-Ear 90s set, the PEX expansion ring interferes with the flush mounting of the drywall backer board for the Kerdi membrane. It doesn't matter if it were greenboard or hardibacker or cement board, these fittings set at the proper depth would interfer with the flushness of the backer board.

This doesn't appear to be some sort of hack on my part. Uphonor makes Expansion Fitting Drop-Ear elbows, and the local supply house sells plenty of them.

Should the drywall just be trimmed a bit to allow for the backer board to sit flush, and just cover the area with the membrane and deal with the small "soft spot" in that location?

Or should I push the drop-ear elbows further back into the wall and merely use pipe nipples to make the connection with the shower arm or hand shower elbows?

 

[John Gayewski]

Either or works just fine.

There is the option of using a cinch clamp and a PEX-B drop ear 90.

But we do either or. We try to get the 90 as far forward as possible without hitting. If it does hit carve the back side of the drywall.

If it ends up sitting back behind the waterproofing you could also caulk it and try to span the small gap. It's not a great choice but it will let the water drip forward instead of behind.

 

[Sponsor]

 

[John Gayewski]

Keep in mind the whole point of this is so you notice the leak and fix it, not leave it leaking. If you left it leaking it would still drip behind the wall.

 

[Jeff H Young]

Ive never worked with Kerdi about 90 percent of my tiled showers are over neither dry wall or backerboard but a standard 7/7 inch lathed scratched and mud so our fip 90 is inside the wall. so the kerdi system the threads and nipple are just barely beaneath the tile, removing temp nipple dosent break "seal" ? If so I like it sometimes my shower arms are too short on tile walls