48 X 48 Porcelain Tile Installation Method.

[OrthoTile]

Good morning,

This forum is a great source of information and wanted to run the issue I'm having with the group.

We are in the middle of a home addition project and we are now at the point of Tile installation. This will be, partly in new concrete slab ( addtion area fully cured) and partly in old concrete slab. We are located in Miami-Dade County. Project is about 2000 sqft. Tile is rectified porcelain, 48x48x1/4". We are using the Peygram tile leveling system, with 1/51 clips.

In this process, we've become keenly aware of the TCNA Handbook, ANSI Standards, etc. We are concerned about a few crack lines existing in the old slab and potential future cracks on the new slab, thus thinking about using some sort of uncoupling.

The tile contractor, initially wanted to install with: Thinset (white Versabond non LFT) on slab, Type-S mortar mix wet (SAKRETE), and then Thinset on tile.

I've spend countless hours studying TCNA, online, etc. and have never found Type-S to be used as a bed. This seems like a variation of the Bonded Mortar Bed Method. But would this work?

Any comments are highly appreciated.

[cx]

Welcome, AS.

If you don't put that geographic location into your User Profile, the information will be lost before we leave this page.

You've strayed from the common realm of ceramic tile into the less common realm of Gauged Porcelain Tile Panels. The industry came out with a new standard in 2017 for such material and installation methods titled ANSI A137.3/108.19. You should probably see if you can gain access to that publication if you can.

For sure, you should ensure that your proposed installation contractor has a copy and that he can show you where it says his proposed method complies with the published material.

I've never installed those (usta be called Thin Porcelain Tiles) materials, but we (TYW) did attend some industry sponsored training in their handling and installation. While it is certainly similar to ceramic tile installation, there are some pretty dramatic differences and you want your contractor to be aware of those and, hopefully, equipped and experienced in their installation.

That said, I've not heard of his proposed method of installation and would be a bit skeptical of it.

As for your concrete slab condition, we'd need at least some photos and/or very specific descriptions to help with an assessment. The first question I'd have is whether one side of any of the cracks is higher than the other side. And that's even a few thousandths of an inch higher. You can sometimes compensate for cracks that are exactly in-plane from side to side, but not those with a height difference.

That includes your concerns "about using some sort of uncoupling." While there are Uncoupling membranes in the industry, there is no standard for them, and you're at the mercy of the manufacturer's advertising department as to their capabilities. On the other hand, there are standards for Crack Isolation Membranes (ANSI A118.12) that might be of more benefit to your installation. Operative word there is might. With those very large panels, it's difficult (impossible?) to shift the crack location in the tile surface.

There is also the consideration for flatness of your concrete substrate. Has your proposed contractor evaluated that on your behalf?

My opinion; worth price charged.

[Tiger Mountain Tile Inc]

Thinset (white Versabond non LFT) on slab, Type-S mortar mix wet (SAKRETE), and then Thinset on tile

I think they intend to build it up like a dry pack but why not just use drypack?

This is the NTCA's find-a contractor page.
And the CTEF's. (This site doesn't seem to be working on Chrome)

You're going to want someone that knows what they are doing for that type of tile.

[OrthoTile]

Thank you for the recommendation and contact info.

The slab showed leveled hairline cracks in a few areas but these were not displaced.

The contractor is evaluating the flatness of the slab to establish flatness. Also agreed to follow TCNA Standards. Crack isolation membrane and a reinforced unbonded drypack mortar bed to level the slab to specs prior to installing the panels.

TY.

[cx]

Originally Posted by AS

Crack isolation membrane and a reinforced unbonded drypack mortar bed...

But hopefully not in that order.

You do understand that the minimum thickness of a reinforced mortar bed is 1 1/4 inches, yes?

There is no need to have a level surface for the tiles, only a very, very flat one.

My opinion; worth price charged.

[OrthoTile]

I'm a bit confused as to your point of "...not in that order."

On TCNA's Handbook and as it refers to concrete slab installations, one of the options is to place a cleavage membrane (paper or liquid) over the slab and over this, place a non-bonded reinforced mortar bed (with a minimum thickness of 1" 1/4). There is certain variation that ANSI standards provides for the mortar bed thickness depending on whether this will be on a commercial or residential setting (ANSI also varies the type of reinforcement used from wire to lath and the position of the reinforcement within the mortar bed.)

I agree. The purpose of the mortar bed is to provide adequate flatness for the LFTs.

Could you elaborate on the comment above?

Also, can anyone in the forum recommend a tile contractor in the Miami area that would do non-bonded reinforced mortar beds prior to tile installation ?

Thank you.

[CaliGrown]

Tile Nation will be mudsetting a wall panel this August and will see if it can become a standard practice GPTP.
For a floor, mudsetting has proven itself. It just might not be best practice for thin panels. If you can get it prefloated then set traditionally, you’ll at least be standing in tested waters

[cx]

Originally Posted by AS

On TCNA's Handbook and as it refers to concrete slab installations, one of the options is to place a cleavage membrane (paper or liquid) over the slab and over this, place a non-bonded reinforced mortar bed...

That would be correct, AS, a cleavage membrane would be required for a reinforced mortar bed in your application.

Originally Posted by AS

Also agreed to follow TCNA Standards. Crack isolation membrane and a reinforced unbonded drypack mortar bed...

But if you also plan to use an optional crack isolation membrane, you would install that on top of your reinforced mortar bed. That was my point.

My opinion; worth price charged.