Subfloor/marble and Goboard/drywall questions

[cx]

'Fraid I don't understand the ceiling description/question, David.

I always want the waterproofing and tile in a tub/shower arrangement to extend at least a few inches beyond the front of the tub and all the way to the floor. Whatever it takes to make that happen is what I think you should do.

Beyond that, I see no reason to extend the foam board around the corner on the wet wall so long as the foam board extends well past the front of the tub, which I can't tell for sure in the photos.

You can tape and finish the foam board/drywall joints as drywall joints so long as they are in the dry area beyond the front of the tub.

As for the wallboard/tub junction, you can stop the wallboard above the tub's tiling flange so long as you complete that joint using a sheet-type waterproofing membrane bonded to the tub flange and the wallboard. I usually recommend giving the membrane a bit of a wedgie into the gap above the flange if possible to provide a bit more movement accommodation.

My opinion; worth price charged.

[SquiredUp]

Originally Posted by CX

'Fraid I don't understand the ceiling description/question, David.

Sorry, it was a lot of info, see a quick drawing below I made of my shower area that hopefully shows a little more clearly what I was thinking. The GoBoard is the light green color. My thinking was it would be easier to transition the two boards on the flat instead of in the corners but maybe that's just not necessary...especially if there are concerns about tile/thinset not taking to purple board which is a sentiment I've seen here a few times.

Originally Posted by CX

Beyond that, I see no reason to extend the foam board around the corner on the wet wall so long as the foam board extends well past the front of the tub, which I can't tell for sure in the photos.

See two more pics I added. The wall extends about 2" beyond the edge of the tub.

Originally Posted by CX

You can tape and finish the foam board/drywall joints as drywall joints so long as they are in the dry area beyond the front of the tub.

What about the drywall to foam board joints in the wet area?

Originally Posted by CX

As for the wallboard/tub junction, you can stop the wallboard above the tub's tiling flange so long as you complete that joint using a sheet-type waterproofing membrane bonded to the tub flange and the wallboard. I usually recommend giving the membrane a bit of a wedgie into the gap above the flange if possible to provide a bit more movement accommodation.

Took me a minute to get what you meant by the wedgie haha but I'm following you now. I need to find out if Kerdie band is compatible with GoBoard bc I cannot find GB's seam fabric anywhere. Any experience with the two materials?

[cx]

In your photo it appears the framing at the left end of the tub is proud of that purple drywall. That the case?

What is the plan for closing the entry to the shower? If not a glass enclosure, I would recommend waterproofing around the corner of the water wall.

My opinion; worth price charged.

[SquiredUp]

Originally Posted by CX

In your photo it appears the framing at the left end of the tub is proud of that purple drywall. That the case?

Yes that is the case…this is what I meant by I would do it differently if I had to do it over again. There is a window about 3 feet off camera along that wall so I can’t really make the whole wall the same plane. And the tub is already installed. Sucks but this is what I have to work with.

For that wall I think I’ll cut back the drywall about 5-6 inches from where it is now, put a 2x4 long ways to nail the drywall to and then fill the space with GoBoard. That way my foam board is extended from the shower wall. The tile won’t go that far into the wall but I’m assuming GoBoard can take paint like drywall?

And then on the wet wall, wrap around the GB like you said.

Does corner bead work with GB as if it was drywall?

[cx]

Well, you're gonna hafta make a "feature" of some sort to deal with the transition from your GoBoard wall to your drywall in any case, Adam. I'd be inclined to simply extend the foam board past the front of the tub as far as you intend to tile, shimming the edge for support over the drywall. I don't see any advantage to cutting out the drywall and adding framing, but you might.

Making a suitable feature out of the jog in wall thickness anywhere but the end of the tile surface might require a bit more imagination than I've got.

My opinion; worth price charged.

[SquiredUp]

Originally Posted by CX

Making a suitable feature out of the jog in wall thickness anywhere but the end of the tile surface might require a bit more imagination than I've got.

I’m actually just thinking now I leave as is and simply tile/foam board up to the jog in the wall and be done with it. Do you see any potential issues with that? I would make sure to make a tight fit around the tub radius and fill the gap with silicone.

[cx]

Originally Posted by CX, Post 18

What is the plan for closing the entry to the shower?

[SquiredUp]

Sorry, we are doing a shower curtain with liner.

[cx]

Makes a waterproof "tub leg" even more important, Adam. Frequently the first point of failure in a tiled tub/shower, and even more so when a shower curtain is the method of closure.

How you want to treat it is entirely up to you, of course.

My opinion; worth price charged.

[SquiredUp]

Gotcha. However I’m unsure if your comment means you’re advocating me to widen the foam board area at the back wall of the shower or just advising me to make that tub leg area as nice as I can with the current structure?

[cx]

I'm just telling you what I think should be the end result, Adam. How you get there is up to you.

Were I using your products I'd want to extend my waterproofing, i.e. your foam board, far enough beyond the tub so that I could finish the little jog in the wall in a dry area using regular drywall products. If I were planning to tile to the edge of my foam board, wherever I stopped it, I wouldn't likely do anything at that jog other then set whatever tile trim I decided upon. But there are always more way to skin any ol' cat, eh?

I just want there should always be a substantial, waterproofed, tub leg.

My opinion; worth price charged.

[SquiredUp]

Ok I’m with you now. And I agree, definitely my biggest regret so far. After talking with you and thinking about it, I think I’ll take your suggestion and extend foam board another 1.5” on the back wall, basically shim over the drywall already there. And tile over that part as well. I’ll have a good 4” or so of time over the tub leg going to the floor.

And the wet wall on the opposite side I’ll wrap the foam board around the edge.

Whew, so many details to consider! Thanks for your help!

[ss3964spd]

Imma little late to this party, Adam, so maybe you're already past this stage.

I can't quite tell what the difference is between the face of the purple drywall and the face of the studs - appears to be maybe 1/4". The foam board will add another 1/2", and the tile another 5/16" to perhaps as much as 1/2" so you're looking to do something with as much as 1 1/4".

If you choose that something to be some sort of trim tile best you secure that now because I've not seen any common trims that can cover that much depth.

[SquiredUp]

Schluter doesn't have any info about this on their site leading me to think it's not that important. I'm using Ditra Heat also in case that matters.

[cx]

You're talking about Ditra Heat, Adam?

Same bathroom as your shower?