Bathtub leak. help - repair water damage [Archive] - Ceramic Tile Advice Forums - John Bridge Ceramic Tile


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05-02-2015, 12:38 PM
Hello all.

I noticed some damage on the wall adjacent to the spot where the tile meets the tub. the seam between the tile and tub basin was grouted not caulked. I noticed discoloration and many, many cracks. I assume that water had been getting in through these cracks and behind the tile, working it's way to the side and then eventually damaging the drywall.

I assumed that I should remove the grout here and fill in with caulk.

Once I started removing the damaged areas I noticed two things. Whatever the backer material is seems to be deteriorated (lots of moisture in it). It is not waterproof and I could not find evidence of a waterproofing membrane in front or behind it at all!


1- Does anyone know what material the backer is? see pictures. It has the consistency of clay (where it is wet) and there is a chunk showing in the pic in my hand. You can also see that it is not the same color as the drywall. it seems to be brownish/gray throughout, about the same color as the drywall paper.

2- If I just re-caulk the tub am I safe moving forward? can I just repair the damage and move on?

3- What is the best method/materials for repair? as you can see in the pics, there is a little drywall behind the tile edge. The last row of tiles are like 2"x6" bullnose strips.

4- How can I remove the thinset from the back of the tiles to replace them after I patch the wall?

5- What backer can I used here? if I fix the tub with caulk is it okay to put drywall back or should I use cement board?

6- Finally, am I totally screwed? Should I be seeing a waterproof layer at this spot. Does this mean that there is no waterproofing behind my tile? do I need to rip it all out?

Thanks all for the advice.

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05-02-2015, 12:53 PM
Looks like they used Hardibacker on the walls, but no waterproofing layer.

The tub leg is usually one of the first places to see water damage, as it's often neglected in the wateproofing process. It's just outside the "wet area", but it still sees some water, particularly when you have a shower door that isn't properly sealed.

In your case, the water seems to have gotten in a little higher than what you would expect from just a poorly-sealed shower door. Does the shower spray on this area?

I don't think you're going to be able to repair this effectively since the water damage goes up several inches above the tub, but it's impossible to tell from the pics. You might turn a fan on it and let it dry out, since the one stud is sideways and will let a little air in. Or you might remove the one tile on the corner and see what you find. I'm not hopeful that you're going to make any effective improvement without at least a little demolition.

If you had a scope camera, it would be interesting to see what you find on the back side of that tub wall.

05-02-2015, 01:11 PM
Does hardi board have a paper layer?
I took another pick which shows a bit of a paper layer on the backer board.

05-02-2015, 01:14 PM
No, it doesn't. I can't tell for sure from your picture what is there, probably one of those things you have to put your hands on to identify it.

Whatever it is, if it's paper-based, it's ruined. Again, I think removing that one tile would be a minimum to assess the damage.

05-02-2015, 02:58 PM
As it happens I am working in the adjacent master bath and have the wallboard off and the studs exposed. Below are pictures if the backside if the bathtub wall, at the opposite end of the location where I have the damage. The substrate seems to be mostly green board everywhere that I can see.

The lower few inches are clearly water damaged here too. With this info I am making two conclusions: The entire shower is backed in green board without any waterproofing layer between the green board and studs, and that I have damage at the lower few inches (only) on all three sides of my tub.

1- what is the likelihood (judging from the pictures below) that there is no waterproofing at all?

2- what is the worst case for me if I just caulk the bottom seem and leave it alone for a while? Knowing that in a few years or ten I will need to get back in and demo the whole shower to properly water seal and replace tile?

Also, is it reasonable to remove the first two rows of tiles, install waterproofing and cement board backing and reinstall those rows of tiles?

05-03-2015, 06:08 AM
1. Jedd, if there's water damage, I don't see how there could be any waterproofing, at least not installed properly.

2. You can try that, maybe it'll work, maybe it won't. Nobody can really tell you one way or the other. Eventually you'll have to replace it, though.

Removing the bottom two rows will certainly get the worst of it, as water damage tends to be on the lower parts of the shower, but until you tear it out, you won't know how far the damage goes. It could be just a few inches, or up two or three feet.