shower corner shelf repair

[reedstrm]

Hi all -
this is Ross, in Houston, TX. I just discovered this site and love the whole thing. But of course, I've got a problem.

I've got a tiled shower, which was done in a remod in 2001 (before we bought the house). Recently noticed some bits of grout starting to fall from somewhere. My wife mentioned that they were coming from under the corner shelf, so Monday morning I'm in the shower, and think "Hmm, is this thing loose? Is it going to fall off? Oops! Not anymore!"

I set the loose shelf on the bench and finish my shower. Then get on the computer, start googling around, and find y'all! As you can see from the photos, the thinset didn't bond very well to the shelf. (And there were lots of voids on one side).

My understanding of what I need to do next is carefully chisel out the thinset, and clean up the shelf, then motar it back in with new thinset. I guess my question is what could have caused the first failure, and what can I do to make sure it doesn't happen again?

Thanks,
Ross

[Jason_Butler]

Hard to say but I bet it's either cheap thinset or the thinset was skinned over when the shelf was set. I'd mix up Versabond ( from Home Depot) and stick it back up there


Jason

[jdm]

You can use duct tape from the edge of the shelf angled up to the wall to support the shelf while the thinset cures. A little caulk around the shelf/wall joint will help to keep out any water. Do this after the thinset is cured.

[reedstrm]

Thanks Jason. We've got other evidence that the tileman on this remod was not the top notch kind of guy I've seen around here: several 'hollow' sounding tiles in the kitchen, and sloppy thinset work on the glass block windows in this shower (you can see through the block that there's voids on the sides)

One though I had: this is a CBU install, so I'd expect some movement between the different wall faces, and in fact, the grout in the corners is cracking (I'm planning on replacing with caulk) Now, I'm a newbie with tile, but if this were would, I'd expect problems with this corner shelf tied to both surfaces - if they move, somethings got to give. Or should the shelf, mortar, thinset, etc. be strong enough to tie it together, and keep it from moving? (then I can skip the caulk!)

Ross

[reedstrm]

Thanks Jeff. I was wondering about support during setting.

Ross

[reedstrm]

Oh, and I meant wood up there, not would. Sheesh, you'd think I talk english much?

[Davestone]

I'd bet he used drywall grout instead of thinset.

[Rd Tile]

These 3 were set with Versabond, not a problem.

[michaelhazuka]

it looks like mastic to me..check to see if the residue resembles a dried, caulk-like substance...I'll put money that the installer used mastic to install the shelf.

Bad, very bad. Clean the shelf off and re-install using a thinset.

[reedstrm]

well, it's mortar alright: I've just spent the last hour or so chisling out one side (going around the edge with a grout saw first, so as not to knock any tile off) Actually, the other work seems fine: the tile is nicely cut around the shelf, etc. I think it was probably just cheap mortar, and not making sure it was really completely seated. The kid's asleep, so that's the end of pounding for tonight. Hopefully, I'll have it all together tomorrow.

Ross