Anti Fracture over mortar bed?

[Nef831]

I’m from Northern Ca. I do my showers using the one coat method. I was wondering if it’s absolutely necessary to use red guard or hydroban etc when installing soft ceramic tiles over floated walls? I been using it every time I install ceramic tiles but I noticed when I pop off a tile the following day or days for what ever reason (chipping , to install a corner bench etc) at first it’s pretty hard to take it out but once I’m able to the tile comes off with the red guard stuck leavening the float nice and super clean , I don’t know if it’s supposed to do that or not ? I’m debating if I should just use flex bond or megalite thinset and skip on the anti fracture

[cx]

Welcome, Nef.

It'll be helpful if you'll enter that geographic location into your User Profile so it remains visible.

I'm a little confused by your title v. your application. Your intent for the use of RedGard on the shower walls is for crack isolation, rather than for waterproofing?

Do you use a moisture barrier of some sort over the backing material on the shower walls prior to attaching your lath and mortar?

Your "soft ceramic" tiles would be a Glazed Wall Tile type?

As to the RedGard coming off the wall with the tile, rather than the tile separating from the RedGard, all I can say is that the failure must occur somewhere and it will be the point of least resistance. In your case, that is apparently the bond between the RedGard and your mortar bed.

The required bond for either surface and the RedGard is only a minimum of 50psi. While it may well exceed that by a significant amount in some applications, it's apparently stronger to the thinset mortar on the back of the tile than to the fat mud on the wall. I find no fault with that, so long as it meets the minimum bond strength.

Your mortar walls would generally be how old when the RedGard is applied?

Your RedGard would generally cure how long before you set your tile?

What bonding mortar are you generally using when you make these observations?

[Nef831]

I use vapor barrier behind the lath and mud I also nail the path to the studs every 6 inches . I’m from Northern California. My intent is to use it as a crack isolation membrane. The walls cure for about 2 days only and the red guard I wait till it’s completely red which is normally till the next day.

[Nef831]

Tile I’ll be installing is 2x8 glazed ceramic tile . It’s name cloe from bedrosians tile. I usually use Customs Megalite Thinset

[cx]

So, that appears to be a yes on the Glazed Wall Tile. That's some pretty porous stuff on the back and given what I'd consider some serious overkill on the A118.15 bonding mortar to both that tile and the RedGard, I'm not at all surprised that removing a tile after the bonding mortar has cured would remove the RedGard from your mortar wall.

I'm not seeing a problem here at all, Nef, except for maybe having that mortar wall sandwiched between the two serious vapor retarders, and with nothing but sand, cement, and lime in there, I can't say even that is likely ever to be a problem.

I think you could save a good bit of dinero on your showers by eliminating the RedGard and using a good A118.4 mortar in lieu of that Megalite, 'specially with Glazed Wall Tiles. Other opinions will vary.