Above the tub question

[Denray]

Shocking, but true, our tile on green-board above our tub has only held up 22 years. Time to fix. Yes, we have a shower there too. Any good ideas (directions) on the proper way to prepare it for tile and or a surround?

If you have building paper and cement board lapping the tub, then you seal the connection at the tub, how does any water behind the tile get to the tub?

Here's what we have now.

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[kurt]

I'm not shocked. I'd never use the stuff, but it'll hold up for a couple decades if everything is installed right.

Not a lot of prep.....tear it out, new paper and durock, install tile. In theory, no water gets behind the tile. In practice, that seems to be how it works.

Unless the grout is done horribly, it's a reasonably good barrier system. Whatever water migrates through the grout dissipates into the rest of the house.

[Denray]

Thanks Kurt. Should the Durock be sealed with some sort of primer/water proof finish prior to tile? And what about the flexible sealant at the tub junction. Does that defeat the drain behind the tile deal?

[kurt]

Some say yes, but I don't. I'd only seal the substrate if it was going to be a steam shower.

There is some element of the pedantic in this "draining tile substrate" idea. Chicago is a tile town; I've installed dozens, and inspected thousands; there's no good evidence to show that the drainage plane capability of the durock is ever required (unless it's a steam shower).

Steam showers are special animals; all sorts of stuff has to happen with a steam shower; a regular shower, not really. I'd use the success of your greenboard shower as an example. Yes, eventually it fails....about the time most folks want new tile anyway.

The durock does dissipate a lot of moisture through evaporation; it's mostly air if you look at it under a microscope. I'm sure there's someone somewhere that is sure it needs to run water like a rain screen, but it's really not necessary.

I use 30# felt 1/2 lapped under the durock, tile it. I use admix for the grout; makes it pretty much impervious. Don't use grout sealer; it's unnecessary and useless anyway.

[Denray]

So the 30# laps every half sheet. It laps over the tub rim too? The Durock laps the tub rim? Or just butt it all to the top of the tub and the tile laps the rim. The admix is what exactly? Something that makes it waterproof?

If I had used whole tiles instead of the tiny ones and new what the heck backer rod was way back when we did it and never had the bright idea of using grout as the tub/wall sealer the thing would still be working.

So my wife hears a dripping noise through the P-trap opening while we are monkeying with this, goes under the house, finds a hot water leak that has been going on for 3 weeks at least turning every sq inch of insulation into a rain forest. Sheesh.

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[kurt]

No, sorta, yes, stuff you add to the grout to make it better, and sorta yes.

There'll be admix next to the grout at the big box. Directions are on the box or bottle.

Again, there's all sorts of opinions on this nowadays with the advent of TV star contractors, but it's really pretty simple stuff.

[Denray]

Thanks for your input Kurt. I'll google my way to a finish. Definitely seems that if the grout is waterproof, then whats the problem. And get rid of the drywall.

[Scottpat]

Denny, you need a can of that spray on rubber sealant to seal that pipe! Ya' know the stuff that the guy sprays the screen door on the bottom of the boat and then puts it in the water! []

[Denray]

Beat you to it Scott. We sprayed the whole area right away with 17 cans of that goo in order to keep the water off the dirt below. It's all sealed up nice and tight now.