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05-05-2015, 08:04 PM
This house is in southern New Mexico. I have removed a section of bad concrete. It is about 14' long and 4' wide. I plan to replace this section with 16x16 Saltillo tile, and make it level with the remaining concrete floor.

I've removed the bad concrete down to dirt. There remains a section of cement that was probably underneath a fireplace. I plan to remove enough dirt to pour 4" of concrete and leave another 1 1/4" for Saltillo and mortar (Saltillo is about 3/4" thick and use a 1/2" trowel for mortar). The concrete will be thinner where it goes over the old fireplace bed.

The adjacent cement floor has been ground flat. I plan to stain it with a water-based stain (BEHR from Home Depot).

So many strong opinions about Saltillo installation out there, and basically 2 schools. How should I do it?

Since I'm pouring the concrete, I've considered setting the tiles directly in the concrete. Do or Don't?

Do I understand correctly that the mortar I use to set the tile is Type S Masonry mortar (not thinset because I won't be troweling a thin layer) ? Is 1/2" square-notch trowel correct, or something bigger? I suspect I will back butter the tiles with significant arching to fill that pocket up.

I've been told not to wet this tile during installation to keep swelling limestone pockets from popping the surface off (and others say soak them all in a wheel barrel). So, soak or not? Cut wet, or cut dry?

I'm doing 1/2" nominal grout lines. Am I grouting with masonry mortar, or special Saltillo tile grout?

Let's start with that.

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05-05-2015, 10:05 PM
Regarding step one, pouring new concrete: Do you plan to tie it in to the existing concrete to prevent settling?

05-05-2015, 10:12 PM

Yes. I would drill into the edge of the old concrete and insert rebar stubs. Are you suggesting to do just that kinda thing? or keep it separate?

05-05-2015, 10:23 PM
I would do just as you described. You don't want that section moving independently of the rest of the slab.

I'm sorry I can't answer your other questions about the saltillo tile installation. It's not something I've done before. The only time I've seen it done, the tile faces were all sealed prior to installation. Is that the best way? Dunno.

I'm almost 100% sure you should seal them before grouting, though, for what it's worth.

05-05-2015, 11:46 PM
I think I've got this straight, but they do not recommend installing tile on a slab until it is at least 28-days old. In the process of curing during that time, it shrinks a fair amount, and your tile bond will be compromised. There are several membranes (Ditra is one) that allow you to install tile as soon as the green concrete can be walked on - generally the next day or so and maintain their warranty.

05-06-2015, 07:25 PM
This brings back nightmares. :crap: It has been a long time but we used to install it the old school way of soaking the tiles, letting the water drain out of them for about 30 minutes and then setting them with thinset. I wouldn't set them with type S mortar, they won't stick. The half inch notch trowel is about right, might actually need to be a bigger notch. Half inch will probably work if you skim coat the backs first and fill the centers if they are cupped real bad. I remember having a 3/4 inch notch for real warped tiles. A bag of thinset would install about 30 sq ft best I remember. The whole reason to soak them is to get moisture in them so they won't setup the grout too fast. So I would advise grouting them the next day before they dry out too much. I have had to drag the water hose in and wet down the tile again before grouting. Not good if the tile is over a wood subfloor. Also, just because you plan to use a half inch notch, it doesn't mean the tiles will build up a half inch. Probably closer to 1/4.

Efflorescence usually shows up after about a week and we would wash it with a mild acid wash to remove it. This can be dangerous to you and any metal inside your home so read up on it if you plan to do this. A week after the acid wash, the tiles would then be sealed. Sometimes a stain and then a sealer.

We also used to install presealed Saltillo tiles. They installed the same way but without soaking. Grouting was a pain because the tiles would dry out the grout real fast. But, Saltillo is probably installed more this way these days rather than the old school way.

05-07-2015, 02:52 PM
Thanks. I see from the comments that thinset is the right mortar, and that a 1/2" square-tooth trowel will work if I fill cupped tiles and pour the floor to allow 1" of space for tile and mortar (rather than 1 1/4").

Nobody is recommending setting the tiles in wet cement (really traditional, really old school). I was curious since I'm pouring the cement fill. But only Davy has offered any experience on setting unsealed tiles wet vs. dry.

I have seen from earlier threads that Davy, John Bridge, and CX recommend mixing your own grout with fine mason sand and portland 3 to 1.

05-07-2015, 04:20 PM
Scott, you can leave whatever room you want for tile. If you plan to use a reinforced mortar bed (recommended), you must leave a minimum of 1 1/4" for that and install welded wire mesh in the vertical center.

If you want to use a bonded mud bed over your new concrete, you must leave a minimum of 3/4" for your mud.

And you're gonna need to honor the joints between your old concrete and your new deck mud through your tile surface.

My opinion; worth price charged.

05-07-2015, 05:57 PM
Umm, Mortar beds? I'm not sure of the image this should be conveying to me. I know that mortar beds are used to form shower bases, but I didn't think I would be doing that here on top of the cement.

Let me describe some of the things in the original picture, and see if I get the same responses. The walls in the picture are made of rock (20" thick rock exterior walls). I cut out a section of cement floor slab, all the way down to dirt. The exception is that there remains a deeper patch of cement in the center of that probably once had a fireplace built on top of it. The remaining cement floor in the rest of the house is composed of 2 layers: The original, then a top coat when the house was add on to (possibly in the '40's).

So CX, I was going to pour me 4" of reinforced concrete where allowed (dig in the dirt deeper for 4", but pour shallow over the leftover fireplace block) and bring the new concrete surface up to 1" of the floor surface. Then thinset with a 1/2" trowel, then 3/4" Saltillo.
Three 16" tiles cover the width, plus leave room for 1/2" grout line, both sides, where the new tile abuts the old cement floor.

so..., mortar bed goes where?

05-07-2015, 07:16 PM
Like I said earlier...keep in mind that industry standards call for that new pour to age at least 28-days before you tile it UNLESS, you decide to use a membrane on top of it that has been tested to isolate the moving slab from the tile (Ditra is one).

If I understand your last, you are only going to tile the new slab? You want it to be level with the rest of the floor? Is 4" thick enough for code in your area? IF the dirt is really just dirt, you may need to dig out some more and provide a better substrate. The existing slab doesn't sound like you have any vapor barrier beneath, so you don't have to try to make a good seal to it in the patch.

05-07-2015, 08:24 PM

Right, the patch will be tiled. The adjacent floor will not; it will be stained. So the new tile will be at the same height as the old floor, and all will be flat (I was going to say level, but its not that kind of house. This part was built around 1900). Also, definitely no vapor barrier under that old floor. Occasionally, though, a squirrel.

To your other points, also a 28-day cure, 4", and compacted substrate for the concrete.

09-04-2015, 08:00 AM
The project is moving along. Here's a photo of the installed tile strip, and a photo of an adjacent room that is also tiled. I chose to seal the floor and tiles first before grouting. The tiles are ungrouted now. The edges of the tile are not sealed. I think I will wet the grout groves, then add grout made from 3 parts fine sand and 1 part portland cement.

09-04-2015, 08:24 AM
That's what we always used for grout, Scott. Given the color of your concrete, you might wanna consider adding some color to your grout. You'd need to experiment with the quantities, but some chocolate cement coloring mixed with your gray Portland/sand mix might give you a nice light brown tint to compliment the Saltillo and concrete colors I see there.

My opinion; worth price charged.

09-04-2015, 05:43 PM
If you have time to experiment, I would check out the Precision grout made by Qwikcete. It's in the white and orange bags at Home Depot near the bags of concrete and sand mix. This stuff works well and gets hard. There are also Saltillo grouts on the market.

Be careful and don't apply too much water in the joints. I have seen efflorescence form under the sealer along the edges from adding water. If that happens, there's no way to remove it without stripping the sealer. Don't ask me how I know this.

03-02-2016, 12:22 AM
I just used a mix of portland and fine sand for the grout without adding any tint. I saw some tile work elsewhere where stain had migrated into the clay tile (another building, some other place, someone else's problem). I didn't want to discover it happening to my tile, however. But I assume, properly sealed, it will never happen.

03-02-2016, 12:43 AM
Here is a picture of the kitchen area. The Saltillo tile, grout, and concrete stain has a water based sealant. The countertop is reclaimed marble. The overhang on the island is supported with 1/2" x 4" iron out to 5" of the edge and spaced between 12" and 18" apart. Its attached with silicone sealant. I cut the marble with a diamond blade and polished the edges by wet sanding with sandpaper, ending at 2000 grit.

03-02-2016, 01:07 AM
Here is a bedroom photo. This floor is stained in dark brown. I acid etched beforehand. In contrast, the kitchen cement was prepped by grinding off black mastic and grinding it flat, rather than etching.
The bathroom has tile set on the cement floor using a flexbond mortar. I used sanded grout on the flat surfaces and matching sanded caulk in corners and surfaces associated with the tub. The tub surround hasn't been built yet. The rock is a pre-existing wall.