Question on alcove tub flange water seal

[Giantsean]

Hi All,

I had these question and pics as part of an older thread, but investigating the problem more I found I had a lot more questions than might be contained there, hence a new one.

We have a drop in whirlpool tub in an alcove configuration which has a flange around three sides. This setup has developed a leak that we thought was originally from the plumbing (it was, but there's more). In the process of fixing that issue, we found a lot more water coming out from the back sides of the tub flanges through the wall.

My question is, are these meant to be fully waterproof from the factory? Originally I had thought this was the case, but perhaps they are simply riveted on and make a press seal at best, allowing them to flex over time and letting water escape. Had this problem existed at the rate it leaks now for the two years it's been installed, I doubt there would be a floor left for the tub to sit on.

The water is leaking through the edge of the flange where the tile meets the tub. At the time our tile guy told us we could just grout it because it has a flange, but it's looking more likely that this should have been caulked from minute one, and that the grout had done it's best but eventually gave way to cracking. Which makes me also ask, if water can just drip down any time, and was meant to be caulked, what's the point of the flange in the first place? It's not like it does a fabulous job holding the tub to the wall. Is it just for keeping huge volumes of water from splashing over? Seems like a kind of suspect design overall, and I'd probably opt for a molded flange next time for sure.

Any thoughts appreciated!

 

[Highlander]

For those “drop-in” tubs the flange is usually ordered as a separate item and is attached on site, with a good bead of quality silicone in addition to whatever screws/hardware came with it. If you know the exact brand/model you can find the official installation guide online to confirm this. Maybe whoever installed it missed the silicone step?

(Edit)
Second part of the issue, the tile-to-tub junction should not be grout as there’s no flex available. Fill the tub with water to weigh it down then seal with a bead of good silicone (if you’re really particular about looks you can get sanded silicone in a color that matches whatever grout was used).

 

[Sponsor]

 

[Cacher_Chick]

The finished waterproofed wall surface is supposed to overlap the tub flange. Grout is not waterproof and not flexible, so it should never be used where there is a corner or change in plane.

I would remove any grout that can be removed from that joint and seal it with a bead of 100% silicone caulking. If you shop the tile store, they have various colors to work with what you have now.

If the tub is flexing and allowing a gap to form around the joint, that needs to be fixed before anything else.

 

[Giantsean]

For those “drop-in” tubs the flange is usually ordered as a separate item and is attached on site, with a good bead of quality silicone in addition to whatever screws/hardware came with it. If you know the exact brand/model you can find the official installation guide online to confirm this. Maybe whoever installed it missed the silicone step?

The tub is a Kohler 1157, and the flange came pre-attached. At the time it was installed I was not as inclined (read: smart) to check these things and assumed it was how it needed to be. My thinking is that they don't come sealed to the tub from the factory (simply riveted on), or somehow that sealing failed over time, due to movement or some other factor. Fixing THAT part would require pulling the tile, so I am focused on sealing the inside.

The tile and cement board both overlap the flange. Instructions don't say that you CAN'T do that (they are a bit vague and generic - not model specific at all) but I think more could have probably been done before it was all installed. For now though that ship has sailed