Shower Bench Builder

[travisinfla]

why use mastic if the price is not much different then thinset

[cx]

Jeff, all modern organic adhesives (Mastic) meeting ANSI A136.1 are acceptable for use in residential shower walls, but not shower floors. The Type I Organic adhesives must exhibit 50 psi shear bond strength after 7 day water immersion.

While many of us on these forums recommend against use in that particular application, it is not prohibited by the ceramic tile industry.

[Edit] Travis, the cost of organic adhesives is much higher than that of most thinset mortars. It's generally used to eliminate the need for mixing the mortars.

My opinion; worth price charged.

[jeffnc]

I hear you, but I would just ask, if it's acceptable for walls, how about the bottom row of wall tiles? That corner touches the floor tiles. Or how about the seat of a bench? Is that a wall or floor? How about the corners of the bench?

They also allow other borderline things, like installing tile directly over plywood. Things that aren't necessarily going to immediately fail, but start increasing your risk. For that matter, you can build showers with no waterproofing and some of those work and don't leak. I've seen tiles in showers installed directly over drywall and it worked. It's about risk tolerance.

So if anyone wants to install shower tile with mastic, it might work. It's just not for me and I wouldn't recommend it.

[cx]

Jeff, I have the same questions as you in your first paragraph. I was just pointing out the industry standards for clarity. I can say that my own ad hoc testing indicates it would probably work in many of those applications. But, I would also agree with your bottom line. I wouldn't use it in a shower, either, and I don't recommend it.

[travisinfla]

The builder owned up it to its mistakes and is paying for a complete demo of the shower and rebuild. They should, but I'm sure that's not often the case, so I give them credit for that. Unfortunately it likely will be the same outfit that originally did it. My guess is they will want to Durock the walls, and then liquid waterproof it, along with the concrete bench.
I wonder if it would be better protection for the walls to thinset Laticrete HydroBan sheet membrane sealing tape to reinforce corners, seams, screws holes in addition to liquid waterproofing rather than just than thinset alkaline resistant mesh tape those areas and liquid waterproof over it?

[jeffnc]

You don't hear many stories here about how the builder came back and redid it all, so that's good. It seems reasonable to ask for a different crew/company to rebuild it with a different technique. I would think the builder would want that as well. They just sub that stuff out anyway. As to your actual question, I don't use HydroBan so I can't say.

[ss3964spd]

Using an alkali-resistant mesh tape, thinset mortar to bed it, and slathering the whole of it with liquid water proofing would be perfectly acceptable, IMO, as long as application of the water proofing is done properly.

How they intend to do the floor, and tie the water proofing into it, is also important.

I'd want to see their plan.

[travisinfla]

Thanks for info. So durock seams, screws and corners should be fine with alkaline mesh tape and thinset bed to mortar with liquid membrane over top .

They (probably) won't waterproof the shower floor, because its recessed 6 inches on a concrete slab, because that's how Florida code rolls. Im still mulling it over. There is 3-4 inches of mud preslope sitting on top of a concrete slab floor. The tile is simply adhered to the preslope with thinset. It's sloped properly, no pooling issues.

John Bridge's book shows a cutout of Kerdi sheet membrane on the shower floor with liquid membrane around the edges of the floor, and up a few inches on the walls. My concern is water getting underneath the floor sheet membrane where it meets the liquid waterproof. Maybe it's best to use 1 waterproofing method for the entire shower whether it's liquid or sheet.

[travisinfla]

for the showerfloor what about just waterproofing the existing tile, tile over tile and then just dropping an extended drain cover over top

[travisinfla]

thnx for all your help you probably saved me 10k but sorry it didnt go to a fellow tile pro. im going to do the drain and shower floor myself. im going to laticrete prime n bond over existing tile floor and then laticrete liquid membrane over that and tile over top. i know your thoughts that using solely a liquid method on a shower floor is iffy but ill follow manufacturing instructions to a T and its on a recessed slab on first floor so im ok with this method.
regarding the drain ill need to extend the pvc pipe so ill need cut around the existing drain several inches down to install a pvc coupler to the existing drain pipe and then extend with pvc pipe. digging into preslope concrete is no fun, dont want to damage the existing pvc pipe. do u use a jackhammer or chisel or both. maybe jackhammer away from pipe and chisel off cement near/on pipe? suppose could use a wet saw too. thnx

[ss3964spd]

Since you don't know what make/model drain was used you won't really know how much of the tile needs to come out around it before you can get to it.

Once you can get to the drain you'll need to cut the pipe the drain body attaches to, the riser, somewhere below the joint where the riser and drain body attach. Hopefully there will be some space around the riser, but if the concrete is packed right against it you'll have to chisel it out so you'll have space to insert a coupler.

How will you tie the membrane to that short dam at the step down from the main floor?

If you have to remove existing tile from around the drain to remove it, what do you intend to use to fill where the tile was?

[travisinfla]

No just some sort of Oatey drain.
Thanks for education on getting to the drain.

How will you tie the membrane to that short dam at the step down from the main floor?
-Good question, can't I just membrane up to it, or remove the tile edge and waterproof under it. Not much water there though and it's concrete underneath.

If you have to remove existing tile from around the drain to remove it, what do you intend to use to fill where the tile was?
-Refill hole with deck mud and then bond the drain flange to the mudbed with thinset so its level with existing tile surround tile edges?
This flange
http://flofx.com/wp-content/uploads/..._Userguide.pdf

__________________

Dan

[travisinfla]

I bought a FloFx PVC drain and Rodkat custom foam pan that is compatible with it. Im going to remove the tile, and dig up the shower floor slope, then use self leveling underlayment, and then thinset the foam pan to it, but wasn't sure how much of the existing slope I should remove before I use the self leveling underlayment. Thanks.
The preslope is 3 to 4 inches

[ss3964spd]

If you remove all of the pre-slope bed, Travis, you may not need the self leveling compound.

[travisinfla]

it will result in a lower step down from main floor to shower floor but maybe not enough so its awkward to step down, ill also need to see where the pex is buried from shower handle to shower head since there on opposite sides of shower, hopefully not routed through pre slope. i suppose i could reroute through attic if necessary