USG Foam Board Question - Tile Flange & Custom Niche [Archive] - Ceramic Tile Advice Forums - John Bridge Ceramic Tile


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06-23-2019, 10:02 AM
I hope this is the right thread, if not I can always create new one. We recently installed USG foam board for our shower over a prefab dreamline shower base. We are doing a custom niche. Videos for the foam board are kinda vague. We installed the foam board 1/8 above the flange and the flange is recessed behind the foam boards. To waterproof/seal between the boards and flange should I use the sealant then thinset the membrane band? I've also seen for other systems where people just use the sealant and mesh tape. Or is there another preferred method. For the niche, I presume I will need to thinset and use the membrane in all corners and I cant just use the sealant? Thank you for any help/guidance anyone can provide.

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06-23-2019, 09:17 PM
Welcome, Jena. :)

If I understand the question, what you want to get is some of the USG Durock Shower System membrane. It's available in rolls about 5" wide and what you wanna do is bond it to your tub's tiling flange with their proprietary pookey or similar and bond it to your foam board with thinset mortar.

If you'll go to the Schluter Kerdi website and download the Installation Handbook (, you'll find the best description of that method I've seen and it has useful photos, too. I believe it's on or near page 33 or thereabouts.

My opinion; worth price charged.

06-24-2019, 11:48 AM
here's a video link that shows the durock niche installation with foam board quite well: foam and niche and install of the membrane to lock it all in. The niches are available in various sizes, and are very high quality.

edited for context.

06-24-2019, 01:05 PM
The tile flange is around the shower base. The niche is separate - the hole is cut out of the foam board and framed out but I havent installed the foam board inside of it. Sadly we couldnt use the preformed niche and have to build our own. It is a small bathroom and small shower (33" corner) so we couldnt utilize the whole width between studs - our niche is tall and narrow. I do have the membrane tape and usg sealant. Thank you for everyone's responses!

06-24-2019, 02:13 PM
ok, good. So my response doesn't quite apply, I'm going to edit to keep your question on track.

07-09-2019, 05:00 PM
So apparently we messed up our niche placement (I'm not sure where our measurements went wrong). The bottom was supposed to line up with the grout lines. I'm using 3x6 subway tile. And when I just did the initial layout there is a 1/2 inch tile needed at the bottom which seems too short. The niche height seems to be right so if the bottom doesn't line up then the top won't either. Suggestions on what to do??? I am very frustrated with ourselves right now. This is my first tile job. Picture attached to show where last tile would be if I lined up the niche with grout line.

07-09-2019, 06:55 PM
Hi Jena,
Do you have another photo of the larger wall section? Some perspective might help us.

Don't be too hard on yourself, I recently did the same thing! My issue was I incorrectly assumed my tiles were actually 4" tall, they measured slightly under and by the time I got to the niche, my pattern was no longer centered between the tile rows.

Is your niche sized to perfectly fall into the courses of tile? Have the wall tiles below the niche already been set?

07-09-2019, 07:06 PM
Like Matt, I'm not sure exactly what I'm looking at.

Measurements have to be exact when trying to do that. Sometimes I'll leave the inside of the niche bigger than need be and mud it in after the wall tiles are set.

07-09-2019, 07:57 PM
I think we forgot to consider the 1/2 inch foam board when measuring from the bottom. Original picture is from the shower base showing where the last tile would land in comparison to the shower base. (And sorry I don't know how to reorient the pic)

07-09-2019, 08:06 PM
What about making the niche 1 tile shorter? Raise the bottom of the niche 2.5” by thinsetting in some foam board offcuts or similar. And shim down the top of the niche in a similar manner.

07-10-2019, 05:41 PM
Won't that mess up the height of inside the niche. I am guessing at this point something isn't going to line up.