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BPinWV
01-12-2017, 04:12 PM
Hello,

I'd like to thank you for taking a look at my question. I've looked through the forum and have found bits and pieces of my solution, but can't find exactly what I'm looking for.

I'm not a professional, I'm a weekend Do-it-Yourself guy. I feel like it's better to invest the time and money and learn the task in case it comes up again. This one has me at my wits end, and I'm afraid of making a mistake and covering it up only to find 10 years from now I screwed up.

When this house was built in the early 70's, it was done in a hurry and on the cheap. The tub was finished with drywall and covered with mastic and tiled. And a few years ago, I noticed a leak downstairs that led me to this tub. Once I started into the repair I ended up tearing it all out.

You will note that my pdf sketch shows how the tub is now, after I added furring strips. The durock is not installed, I'm considering how to do it

You might ask why I installed furring strips: the tub was installed crooked, and in places 1/2" away from the studs. I wanted the back side of the durock to be within the flange of the tub.

Sorry if I'm adding unnecessary details, I'm new to this..

I'm at a point where I can't put off installing the durock any longer, but I can't figure out how to seal it. I will be using Laticrete Hydroban to seal the face of the durock, but I'm worried about the area nearest the tub. My understanding is this is usually sealed with silicone after the tile is installed. I'd like an extra layer of protection.

My idea, and please comment, is to bring the durock down to 1/4" above the tub, and seal it using Sikaflex sealant. But Sika doesn't exactly recommend using it on tubs.

I am eager to hear your comments and suggestions. I should probably pause before I write a novel. I will post more photos as the project moves along.

I appreciate your time looking at this.

Thank you,
Bruce

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Houston Remodeler
01-12-2017, 08:41 PM
Bruce,

1- The industry standard is to leave that space open. You can bridge the gap with the hydroban.

2- Sikaflex construction adhesive and their sister product the sealer are both excellent products.

3- You can fill that joint with sealant, let it fully cure than hydroban over everything. There are no tile police.

JeffCar
01-12-2017, 08:46 PM
Bruce, I am a newbie as well working my way through this same thing. I installed a new Koehler tub, have installed furring strips to bring the attachment point for the Hardibacker (my choice of backer board) inside the tiling flange for the tub. After having read a lot about waterproofing the tub to wall connection, I have chosen the method you have - bringing the backer to within 1/4 or 3/8 of the decking, tiling just a bit beyond the backer, and filling the resulting gap behind and under the tile/backer combo with silicon sealant. I am using Redgard on the Hardibacker to waterproof it. The silicone IS made for the purpose, and bonds well to all the components. I've seen the Sika sealant used outdoors to seal joints between concrete and concrete, or concrete to plastic/composite. Seemed to do fine, but if the product isn't calling out its use for your purpose, I'd think twice about it.

Did the tub manufacturer recommend an approach to the question? This is in line with the recommendation Koehler.

Hope this helps! As I said, I am a newbie with this too, so you probably want to let one of the experienced guys comment before moving on....

Houston Remodeler
01-12-2017, 08:48 PM
Don't forget to apply the same treatment to the side of the tub in the 'tub leg' area

cx
01-12-2017, 08:59 PM
Welcome, Bruce. :)

Let me just add that the sealant between the wall tile and the bathtub is not part of the waterproofing for the shower. That's an entirely aesthetic consideration along with allowing for movement between tub and wall structure.

Your waterproofing should have a connection between the wall waterproofing and the tub, which is not always an easy thing to do with a liquid-applied direct bonded waterproofing membrane.

I do believe Laticrete makes a reinforcing fabric to be used along with their Hydroban and I believe the Hydroban is advertised as being able to adhere to materials such as your tub is likely made from. That's the type of waterproofing arrangement you really want.

My opinion; worth price charged.

JeffCar
01-12-2017, 10:31 PM
Now I am confused. CX, so if you are using a waterproofing material on the front of the backer, you are theoretically restricting water penetration to the tile/grout layer. If you seal under that layer with silicone, how is the water released?

If you are allowing water to potentially penetrate the backer board to waterproof sheet behind, attaching the sheeting with some form of membrane to the tub flange. If that flange is sealed with caulk, where is the water to go?

I thought I had understood this, but maybe not?

I don't mean to hijack this thread... just trying better understand the process which I believe benefits both Bruce and me.

BPinWV
01-12-2017, 11:33 PM
Houston Remodeler, thank you, I like #3. That's probably my best choice. I'm not 100% sure that the Hydroban will stick to the urethane sealant though.

BPinWV
01-12-2017, 11:41 PM
JeffCar, I'm glad to hear from you. I've scratched my head wondering why this issue isn't discussed on every tub surround thread. If you're dealing with it, I know I'm not crazy.

I'm not particularly fond of any sealant, I chose the Sikaflex because it's urethan based and hence it's tough. But I want something that will last forever (haha), and I'm having to compromise here and there.

Personally I'm not a big fan of silicone, I've had too much of come off after a few years. And since this joint is going to be covered up, well you see my problem.

BPinWV
01-12-2017, 11:56 PM
Hi CX, thank you!

You hit the nail on the head here:

Your waterproofing should have a connection between the wall waterproofing and the tub, which is not always an easy thing to do with a liquid-applied direct bonded waterproofing membrane.


Laticrete does make a fabric, which I have, it's mainly for corners, and abutting edges of Backer-board.

The Hydroban isn't designed to be exposed to the air for more than 30 days without being skim coated with thinset. I could over lap the gap between the durock and tub with the fabric and then paint on Hydroban. Then when the tile is set there would be thinset on that 1/4" gap area. Except on the back side. But my main problem doing this, is that the Hydroban isn't design to stick to the porcelain tub, at least not permanently.

I hope I'm not being a pain. I appreciate you and the others helping work through this.

Houston Remodeler
01-13-2017, 07:59 AM
Oh it will

jeff_free69
01-13-2017, 12:35 PM
The Hydroban isn't designed to be exposed to the air for more than 30 days without being skim coated with thinset


If I might interrupt - Are you sure about this?

I didn't recall anything like this, so just double checked the product sheet and its a little less stringent.
"Do not expose unprotected membrane to sun or weather for more than 30 days"

Due to unavoidable inturruptions, I've had a bathroom wall (no sun or weather there) completely primed with Hydro sitting for a couple of months, so I' really hoping its not an issue.
I'm finally getting around to setting the tile - wondering if i should do a another quick coat first???

BPinWV
01-13-2017, 02:36 PM
Hi Jeff_free69, I've driven the Tech support crazy at Laticrete. They told me a couple interesting things that really should've been spelled out in the Tech Data Sheet. The first thing is that 30 days is the max amount of time the HydroBan can go uncoated and still be in warranty [hmmm].

The second thing that I found interesting, was they advise only two coats, and said that if a third coat is applied the second coat won't cure properly. This seems a little confusing to me, if one lets the second coat cure for a couple days. He said "more isn't better" in this product.

Tech Support has always emphasized skimming it the same day [or next day] it's applied.

But I understand your dilemma, you're thinking about just refreshing the Hydroban surface, you might give them a call. Laticrete Tech Support 1-800-243-4788 Ext.235

BPinWV
01-13-2017, 03:01 PM
I feel like I'm at that all too familiar place, where I have to take a leap of faith.

I'm unsure whether the Sikaflex will permanently stick to the porcelain tub.

I'm unsure whether the Hydroban will permanently stick to the Sikaflex.

I'm unsure whether the Hydroban will permanently stick to the porcelain tub.

And since both Tech supports (Sika, Laticrete) aren't going to extend their warranties for me, I'm stuck in the middle looking into the abyss.

And like Houston Remodeler said Don't forget to apply the same treatment to the side of the tub in the 'tub leg' area

This is the area that has me most not wanting to screw this up.

miss0033
01-13-2017, 04:19 PM
I was skeptical of Kerdi-Fix, but I used it anyway to seal my Kerdi to the tub flange. I also used it to stick some scraps of Kerdi to a couple different things - a scrap of PVC pipe, the tank of the toilet I removed and a piece of wood all the same day I applied it to the tub flange.

It was stuck pretty good. I eventually separated them, but had to use quite a lot of force and damaged the kerdi far before I removed it from what I stuck it to. Those adhesives and sealants work quite well, and you will likely not exert anywhere near the force I had to use to remove them.

Houston Remodeler
01-13-2017, 06:19 PM
You can always perform your own field tests to see what sticks to what. The drivers side fender on my work trailer is the unlucky recipient of my horrible driving. I've torn it loose a number of times. The rivets are shot. For the last year or so, its been held in place by a nice thick bead of sikaflex. The license plate holder / light bracket is held in place by PL Premium. The crank handle to the jack is held on by Nobleseal.

You've got a list of excellent products that work well together IMHO.

jeff_free69
01-25-2017, 12:53 PM
Hi Jeff_free69, I've driven the Tech support crazy at Laticrete. They told me a couple interesting things that really should've been spelled out in the Tech Data Sheet. The first thing is that 30 days is the max amount of time the HydroBan can go uncoated and still be in warranty [hmmm].
...
Tech Support has always emphasized skimming it the same day [or next day] it's applied.

But I understand your dilemma, you're thinking about just refreshing the Hydroban surface, you might give them a call. Laticrete Tech Support 1-800-243-4788 Ext.235



Bruce,
Jsut following up - I took your advice, and they confirmed what you said (I didn't press them on why the product data sheet doesn't really say this).
They also recommended that I do a test tile (and if it fails, rip it all out!!! )
Fortunately it stuck good :)

Thanks,