Fill bathtub before caulking?

Rav

I'm about to re-caulk between our cast-iron bathtub and the wall tile. I've seen a few references in various places to filling the tub with water first prior to caulking, so that ultimately when taking a bath it doesn't stress the caulk by over-yanking on it. Caulking with a tub full of water doesn't sound particularly easy, and I don't know if people here think it's ever necessary, but since this is cast iron and of course very heavy, is it even less necessary? Thanks.

jagans

Wrong.

You are not supposed to caulk there. Tubs have an apron that goes up behind the substrate below the tile, which is either MR sheetrock (CRAP)
or a decent board like wonderboard, or Duroc, which is a reinforced cementitious product. Water getting past the tile has to be able to weep out. Caulking blocks this and often forces water into the wall. If you must seal there for aesthetics, do not place a large coved bead there, it will block water from exiting the system.

__________________
" A lot of men build things, and a lot of things fall down "

Rav

Hi, jagans, thanks for the reply, but I'm confused. When I posted a question last month about whether to use Polyseamseal or Silicone caulk for this same project, you responded "Not sure what polyseamseal is, but if its urethane, it is food for mold. Silicone is not. Go color matched silicone." You can see the post at Polyseamseal or GE Silicone II for bathtub caulking ? . And there are a number of posts on this site about caulking a bathtub. I thought that caulk was supposed to be used at a change of plane, such as this? I don't want to do the wrong thing so I'd like to understand your point of view. Thanks.

djlandkpl

I doubt you need to fill the tub. If it moves enough to stretch the caulk, you've got bigger problems. The recommendation is to leave a few weep holes in your caulk line so that any water that does get behind the tile can weep out of those holes.

Rav

As you can see from the picture below, the tub only has one side wall. I assume a weep hole is simply a gap in the caulking. In my tubs case, how many weep holes should there be, in what locations, and how wide should each gap be? And isn't there the potential for water to get IN behind the caulk through those holes?

Attached Thumbnails

 

joecaption

It's standard practice to do exactly like you suggested. Remove all the old caulking (new will not stick to old) clean it, fill the tub then caulk.
If you can wait 24 hours before draining the tub.
Contact any tub manufacture and there all going to suggest the same thing.

djlandkpl

I wonder if that tub even has a flange. After you remove the old caulking check to see if there's a flange. If there is one, you could probably put 1 gap (1/8/ to 1/4 inch) on the valve wall and 2 on the sidewall. The flange will keep water from seeping from the tub to the other side of the wall.

Rav

Perhaps I should have said in the first place that there is no shower in this tub. This bathroom doesn't even have a shower; the downstairs bathroom does, and that shower is what we use the vast majority of the time. This tub is used perhaps 4-5 times during an entire winter, and then not for the rest of the year. Given that there's no shower, and how relatively little this tub is used, is there the same concern for water getting behind the tile, and needing weep holes?

djlandkpl

Yup. That changes it. Just caulk it across, no gaps.

oh'mike

There is no need to fill the tub----that thing is not going to be moving up and down---

__________________
New members: Adding your location to your profile helps in many ways.--M--

jagans

Hi Rav,

When tile is first installed, it is grouted. I think we can all agree on that. As the tile moves from expansion and contraction, the grout tends to dry out and develop voids, cracks, and falls out, leaving an open joint where the grout used to be.

Joe is quite right, the standard procedure is to inject sealant into the void, and tool it. This is fine on vertical joints. The problem I often see is that people tend to gun a large bead of sealant in the angle change at the bottom of the tile and then tool it into a cove shape. This tends to hold water in the tile.

I think the key here is to go ahead and caulk and tool sparingly, and apply a good sealant to the grout.

Im sorry if I misled you, its just one of those double edged swords. I still stick with my decision for silicone over urethane of any type. Urethane is organic, pure silicone is not.

__________________
" A lot of men build things, and a lot of things fall down "

Rav

Thanks to everyone for their input. Jagans, I will definitely use a pure silicone caulk with a mildewcide. And thanks for the advice to keep the size of the bead down and not create a cove.

Javiles

Areas Needs to be cleaned and i mean super clean then grouted and left 72 hour and re-grouted to fill the cracks and voids then sealed. will last longer than silicon or chalk. a little more work in fact if any of the tiles in the wet area is missing grout or have cracked tiles or grout you should re grout the whole area.

__________________

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

Rav

I wanted to let people here know the results of my tub re-caulking project. I've attached a before and after picture. Thanks very much for everyones input -- I appreciate it, and I'm sure the job has turned out better for it. (Yup, the door and frame need re-painting -- another job for another day!) / Rav

Attached Thumbnails