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Steel framing for a shower partition wall – can I leave a hole in the floor underneath the track?

sasharh | Posted in General Questions on

Hi, I’m putting a shower in our downstairs bathroom. The walls are stone and the floor concrete.

I’m building a small partition wall to hide the pipes & mixer for the shower, for which I’m using 70mm steel framing + wet area drywall + Schluter waterproofing. 

In the corner of the room, right below where the framing will go, there’s a roughly 15cm hole (top left in the photo). Normally I would fill in this hole with concrete so that I have a flat substrate below the bottom rail.

However, this is the hole where one pipe currently is, and other pipes will soon join it.

Unfortunately I have no other place in the bathroom where I can put the partition so I’m hoping that I can leave it here and just set the frame over the hole. Normally, I know this would be a no-no but as the partition framing will lie along the wall I will also anchor the vertical studs to the stone wall, so I imagine that it’ll be rock solid.

This is my first time framing so I have no idea if what I’m doing is ok, so I hope somebody that has more experience can tell me if what I’m doing is stupid or not?

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  1. onslow | | #1


    A bit more expansive view of the situation would help. Where are you draining to? What kind of pan for the shower are you planning? I am not seeing stone walls, are they part of the issue? What is sticking out of said hole in the upper left of picture?

  2. sasharh | | #2

    Hi Roger,

    Thanks for your reply. The shower pan (Schlüter shower tray) will be adjacent to the frame so shouldn't be an issue. The walls are stone covered in plaster. I just mentioned them as they'll provide a solid anchoring point,I think. There's a cold water pipe sticking out of that hole. We'll also add a hot water pipe there and a drain for the sink.

    Everything is draining into the garage below, where the existing evacuation pipes are.

    My question was really just about the stability of the metal frame, whether having a hole underneath one end of it should be a problem.

  3. onslow | | #3


    I guess I will have to remain puzzled about some of the details as to where and how you will fit and drain the pan, but floating the base track for the stud wall is probably going to be fine. You indicated that you would be anchoring the studs to the stone/plaster wall anyway, so by the time you add your choice of cement board or greenboard all the framing elements will be tied together. This means it will act in much the same way exterior sheathing unites individual studs into a more rigid overall structure. The bottom track won't be wandering anywhere.

    Metal stud and track elements can be had in different gauges, so if you have the option of going up in stock thickness, it might make fastening to a potentially uneven stone wall more successful and less wavy mess. If light gauge is the only alternative, I would suggest putting horizontal furring strips on the stone wall first to simplify both anchoring processes. Depending on the nature of the stone in the wall, you might find drilling holes a real task. Getting fastener points into the stone exactly where you needed on a stud might be quite a challenge. Getting the anchors set in the furring strip will be much less fussy if you set the anchors between stud locations.

    Putting furring strips down first will make the wall for the valve a bit deeper, but having a little extra "grace" room could make plumbing easier. You could also pre-true the furring strips as you go by shimming as needed. Then you may attache the metal studs without twisting, bending, or fighting slightly off holes in the rock.

    I have only used the Schluter system once, but be advised that(historically at least) Schluter said that one must use NON fortified thinset to apply the fuzzy plastic sheet, corner bits, and the tile. If you don't, the warranty may/will be void. The fortified thin sets seem to be subject to re-softening if exposed to long term wetting. I have only seen softened thinset when dis-assembling already crumbling showers. Just the same I have used modified thinset for tiling floors with no apparent disasters or call backs. However, their products, their rules.

    If you are not going all in with Schluter top to bottom, then also be advised that while cement board won't disintegrate when wet like drywall, it can get and stay wet behind tile. Grout lines pass more water than one might think and over time the outward drying through the grout will likely not be enough to avoid having damp cement board behind the tile. Plastic sheeting behind the cement board is not terrible successful if the showers I have taken down are any guide. The holes made by the fasteners allow water to rot the studs and the plastic mostly makes any water build up drain downward to cause havoc elsewhere.

    If doing the walls in cement board, tape and thinset all the joints, corners, and fasteners before coating with RedGard or similar waterproof coating. Then set your tile. If the tiled area is not full height to the ceiling, I would advise using setting type compound for the drywall taping. In one shower repair job, I found that the non-setting compound used above the shower/tub surround was actually soft underneath the paint. The paint and compound peeled off the walls like steamed wallpaper, as did the equally saturated paper face on the not green board version of drywall.

  4. tommay | | #4

    As others said, a better picture would help. Do you plan on putting the valve against that back wall? Not a good thing if needed to replace or service in the future. What about the drain and vent piping? Where is that going?
    Looks like you may have to break out the floor to do things right and perhaps find a way to bring the water piping down from the top instead.

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