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Need advice for gap between tub and tile floor

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Dec 28, 2013, 09:56 PM
Need advice for gap between tub and tile floor
There is a 3/4 inch gap between the tile floor in my bathroom and the tub. The gap opened up over a period of a couple of years after we bought the house. (We bought a "spec-house" new.) The tile appears to have been put down over a backerboard on top of a plywood subfloor. The gap goes all the way down to the plywood, so the gap is about an inch deep. I am attempting to attach a picture. Any advice will be appreciated. Someone on another forum suggested I fill it with caulk, but that seems like a really big space for caulk.

Picture of gap

Dec 28, 2013, 10:31 PM
genuine pure 100% silicone would be what I'd use. obviously something was not stuck down correctly, I don't have walking floors. if the builder warranty is over, I'd put silicone in until you get tired of the blah builder trim and do your own floor. at that point, it appears current standards are to insure you have at least 1-1/4 inch of subfloor tied down well to the joists. mortar and screw down a tile base of cement board or Durock. when the mortar is set, mortar on Kerdi tile barrier, and lay your tile. any heated floor material should go in a mortar bed not much thicker than needed to cover the mat/material, and then of course you cannot use nails or screws, so Kerdi over that and then tile.

not impossible the tub was walking into the wall if it wasn't flange-nailed (if applicable) or set into a foam or mortar support bed on installation.

This message has been edited. Last edited by: swschrad,

sig: if this is a new economy, how come they still want my old-fashioned money?
Dec 29, 2013, 10:03 AM
Thanks. By the way, I'm nearly certain that it was the tub instead of the floor that "walked". It's actually a tub /shower unit. I may end up taking out some drywall around the unit. Do you recommend trying to nail the flange at that point?
Dec 29, 2013, 10:26 AM
I think that you will find over time that you have a lot more going on here than it appears from just this one gap. For the tub to move in the direction that it is going, there needs to be some movement or deterioration in the surround wall at the back of the tub. Could be that there is some water leakage causing rot back behind the surround material. In any event, this will be a slow moving thing.

For the size of your gap, I would fill it with regular grout. Once the grout is cured you'll need to add a bead of a matching grout caulk to cover the seam between the new grout and the tub. I would not go with pure silicon because it will quickly stay permanently dirty - especially in this moisture prone and dirty area where the tub meets the floor.

Overall I think you will have a major rebuild in your future to really fix this problem.

Dec 29, 2013, 03:03 PM

this is just a band aid..but it will work