I installed a set of reclaimed Saltillo tile in a bare concrete slab that has been in such a state for the past couple of years.

Let’s start out with the video:

Reclaimed Tiles

I had a strip of bare concrete slab in front of my theater that needed to be re-tiled.

The rest of the hall is tiled with Saltillo tiles and I happen to have a large selection of recovered tiles from when I deconstructed my living room a few years back.

One downside for re-using old tiles it that they all have a notable amount of mortar still stuck to them that has to be ground off, first.

I say that all of them have the mortar because there’s a bit of a selection bias (or survivor bias?) going on. All of the tiles with mortar that was not loosely attached to the concrete slab ended up being destroyed while trying to remove them. So by necessity, the only tiles that survived the process were ones with the mortar still stuck on.

Some ended up having “things” growing in them after hanging out outside for a couple years.  I have no idea what these growths are — maybe spider egg sacs or something?

Grinding the Mortar

Some of the tiles had mortar in the grooved patterns made by a square notched trowel. I attacked those first with a masonry chisel just to knock down the high spots.

That only goes so far and so I eventually need to grind down what’s left, regardless.

When I first tried this with regular grinding wheel, the amount of dust it kicked up was almost unbelievably staggering. Everything within 10 feet of the tile was covered with dust and some of the dust made it well beyond that. But since then, I discovered the Dust Buddie shroud for my angle grinder and… well, rarely do you find a product that works as brilliantly as this does. Hook it up to a decent shop vac and it not only reduces the dust but it eliminates it! It’s the difference between a stupefying cloud of dust and so little dust that you could probably get away without using a dust mask at all. Amazing product.

After realizing it took two minutes to do a tile with the back completely covered with mortar, thus no way to prep it with a masonry chisel, I decided to skip the chisel step thereafter and just use the grinder exclusively. Why spend the time with an extra step when it takes the same amount of grinding time in the end no matter what?

Cutting Tile

The space requires more partial tiles than full ones and so I needed to do a bit of tile cutting. I tested out the option of using an angle grinder but passed after the first experiments. More on that later. I bought a $99 wet saw from Home Depot. Yes, there is a model that is slightly cheaper both at Home Depot and Harbor Freight, but this one came with a diamond blade for the price and the cheaper ones required buying a $30 blade. In the end, this was the cheapest to just get started.

How good is it? Well… are you used to the professional grade tile saws? Maybe you’ve exclusively rented a higher end saw and have never used a cheap one? If so, then you’d hate this saw with a passion. It’s much slower; bogs down with anything more than a tiny bit of pressure; and is notably less accurate with its fence. But if you don’t have such experience and you want to spend as little money as possible on cutting tile, then this actually works okay. Just take it slow and make some test cuts to calibrate the fence and it’ll cut through whatever you have… providing you have the patience.

One downside to cutting Saltillo is that the red clay dust from the cut mixes with the water and creates a pretty decent dye. I was unable to fully clean this saw after I was done since the clay dye permanently stained some bits of it. Go figure!

I could use the tile saw for all of the rectangular partial pieces, but there was one piece that needed to be an L or a P shape or something like that to go around a corner. I used my angle grinder with a diamond cut-off wheel to cut out that piece. Compared to my cheap tile saw, the angle grinder actually feels like it has a lot more power. I could likely do all of my cuts much faster with it rater than on the tile saw. But man does it kick up a lot of dust! I didn’t want to deal with that with the rest of the pieces. And also, I found myself unable to get a truly straight line when doing it freehand. Finally, the edge isn’t quite as fine with the angle grinder as it is with the tile saw — there are chips taken out of the top and bottom. Maybe it’s because I didn’t keep the wheel perfectly square to the piece? Eh. It all worked out in the end.

I made sure to dry fit everything before starting since installing the Saltillo is fiddly work and I didn’t think I’d have enough time to cut and install it all at once.

Preparing the Tile

One important thing to note about Saltillo tile — its clay content makes it an extremely thirsty tile. So much so that it will naturally try to suck out all of the moisture from your mortar during installation, leaving a very dry mortar that does a terrible job of curing. It also means that any mortar or grout that touches the tile will almost immediately stain the tile permanently.

That’s why the first essential step is to soak the tiles in water preferably overnight but at a minimum for some amount of time before installation.

This was a relatively small project and so my goal was to just re-use leftover fortified thinset from a previous project. I started by pouring in a tiny bit of water into my bucket and then emptied the rest of the bag into it. I then inexplicably assumed that there wasn’t enough water and added more. That was a mistake. It became very quickly clear that my water to thinset ratio wasn’t even close to correct and while you can always add more water later, you can’t remove any. Argh!

Well, I did have an unopened back of slightly different fortified thinset that I wasn’t planning on using for this project. Looks like I left myself no choice. I’m not a big fan of combining two different types of thinset but, well, let me reiterate that I had stupidly left myself no choice in the matter.

With the added thinset, I was able to stir it into a much smoother consistency.

By the way, you’ll note that I’m using a corded drill for this. Experience has taught me that a decent 1/2″ cordless drill sort of works… but not great. The constant use that mixing mortar requires has a tendency to destroy the batteries. That is, not only does it make the battery go dead pretty quickly, but it’ll prevent the battery from charging again. Maybe heat related? In any event, if you’re going to be mixing thick compounds like this then a corded drill is likely going to be the cheaper method in the long run, when you factor in the ruined batteries.

Installing the Tile

The tools I use for laying the tile are, as follows: one 5 gallon bucket with the thinset and one bucket with water. One 6″ joint knife for loading on the thinset. A 1/4″ x 3/8″ square notched trowel to spread out the thinset. A sponge to wipe things down and then some sticks between 3/4″ and 1″ wide to clean out the grout lines.

I went back and forth on the notched trowel size. The question is if the tiles were considered “large format” or not. Most resources I found say to use a 1/2″ square notch with tiles larger than 16″ wide and my tiles are 12″ square. But… these are also notably thicker than most typical tiles and that might factor in, too. Finally, some sites do claim that a 1/2″ square notch should be used even for 12″ x 12″ tiles. Those tended to be in the minority, though.

In the end, I chose the 3/8″ trowel mostly because I already had it and I was planning on back buttering the tiles anyway. A 1/2″ trowel likely would have worked out just fine.

My procedure was to just dump out a bunch of thinset with the 6″ joint knife and then even it out using the notched trowel. Each tile then gets its own individual helping of thinset as I back butter it. I do this because the Saltillo tiles aren’t smooth on the bottom and sound notably hollow if there are any air pockets underneath them. I can hear that on quite a few of the existing tiles in my hallway and in my old living room. I can say from experience that the tiles that sounded hollow also were trivially simply to pop up from the floor, when I was removing them!

One funny note: if you watch the video, I describe how I back butter all of the tiles then proceed to do so for only one of the tiles and not the rest!  That’s because I was actually running out of thinset at that point in the installation since I was on the last tiles.  I didn’t have enough to back butter the final tiles… but I did back butter all of the initial ones.

You can buy very finished looking Saltillo tiles but mine are distinctly rustic looking. They have the multi-colored hues and animal paw prints and the rest. The appropriate grout width for this style of tile is very large — between 3/4″ and 1″. This does make placing the tiles quite a bit easier than some other styles. You’ll note that in my list of tools, I made no mention of any kind of spacers. Well, that’s because I just set the tile down roughly in line with the others and leave it be. There’s no reason to measure anything or get any more precise than it looking right. These wide spaces between tiles also means that’s it’s not as critically important to keep the tiles at the same level since small variations will be imperceptibly this far apart. I do use a level to roughly keep each individual tile from tilting too much, but nothing too crazy.

Oh, it’s worth nothing the spray bottle.  It’s for spraying down the concrete slab before all this. That’s what the spray bottle is for. I do that for the same reason that I soak the tiles beforehand — so the slab doesn’t suck any of the moisture from the thinset while it’s curing.

After setting the tile, I use a few pieces of wood I had lying around to clean out the grout lines. The sheer size of these pieces is probably somewhat unique to installing Saltillo.

I also am very quick to use the sponge to get rid of any thinset that fell on the tile. Even with the overnight soak, these tiles still have the tendency to stain if the thinset is left on for too long. I’m not sure how long that time is, so I just make sure it’s removed ASAP.

It took me just over a half hour to lay down roughly 10′ of tile, or 21 individual tiles, both full and partial.

I then let it set for 24 hours before grouting it.

Grouting

Saltillo is different enough that it has its own special grout mix. It’s maybe hard to find most places but here in the South West, you can find it even at Home Depot and Lowes and the like. In my case, I just used the left over grout that the previous homeowner left and mixed up a batch using the directions on the package.

Grouting is tedious work even in the best of cases and grouting Saltillo is not even close to the best of cases. I mean, it starts out pretty standard, as I just flood all of the joints with the grout mixture. The only real difference here is the sheer amount of grout needed. I mean, with typical tiles, you can get away with a little box of grout powder but with grout joints this large, you need to get it in 50 lb bags.

The next step is also relatively standard in that I take out my rubber float and apply it at an angle to smooth out the joints. I use the same rubber float at a 90 degree angle to essentially squeegee off as much of the grout from the surface of the tile as I can. This would almost be a meditative step if I didn’t know what was coming next.

The final step is to finish the cleaning and grout shaping process using a sponge. Sounds simple, right? Well, the actual motions and such are simple but for whatever reason, this step takes forever. These few tiles that you see before you took about 10 minutes to finalize with my back killing me the entire time. It’s super important to get it all off, too. With typical grouting, you essentially leave a very thin layer on that forms a haze overnight. You can’t leave any grout on Saltillo since that haze will be impossible to remove with chemical means if it’s allowed to stay on overnight.

So yeah, every square inch of the tile must be meticulously cleaned so that it’s absolutely pristine.

When it’s all done, the grout is notably dark and I’ll have to say that I don’t mind the look of it.

Painting the Grout

When it dries, though, it dries to a much lighter tone of gray. You’ll note that the gray is similar to the grout color for the rest of the hall, but it’s not exact.

That’s because the existing grout is actually painted a lighter color than it would naturally be. See, the originally installed tile wasn’t sealed and so the grout became permanently stained. No amount of scrubbing could clean it off. Therefore, a year or so ago we got this Polyblend Renew Grout Colorant and Sealer and went to town painting the grout.

In order to match the existing grout, then, I needed to apply that same colorant to the new grout. This is all one week after it was installed, to give the grout time to fully cure.

Using the Polyblend colorant is straightforward if very exacting. I start by pouring out a very very tiny line directly onto the grout. A little bit of this goes a long way and pouring too much will just make cleanup that much harder.

The actual painting step utilizes an old toothbrush. Yes, that’s literally what is recommended on the bottle. The old toothbrush has fine enough bristles to really get up close to the tile edge without sloppily going over.

My technique is to drag the paint down the middle of the grout to essentially load an entire section. Then, I super carefully bring the paint out to the edges, being very aware of where every single bristle is on the toothbrush. It’s very zen like. Go extremely slow.

Doing just these 21 tiles ended up taking a full day. It took multiple days to do the entire hallway, the first time around. Yes, super slow going.

Even being super careful, though, there is bound to be a few tiny areas where the colorant spills over. I used a wet paper towel to essentially scrub it off.

After it dries, you can see that there is still a color difference between the old and the new. Well, this is exactly the same colorant — same bottle even — so that color difference is just dirt. The Polyblend solution is both a colorant and a sealant so in theory I can just scrub off the grime from the old grout to make it match.

Sure enough! A solution of 50/50 vinegar and water and a little elbow grease and the old and new are indistinguishable. Sweet.

Sealing it All

If there’s one overriding trait of Saltillo tiles that should be clear at this point is that it stains very easily. That means that using a sealant that soaks in is an essential last step in all of this.

Applying this sealant is the easiest part of this entire process. I flood it on using a foam brush but honestly anything at all that can evenly spread it will work just fine. It doesn’t take a lot, either. It kind of has a greasy texture but does soak in readily. In the case of the most porous tiles, a couple coats was needed but otherwise only one suffices for most of them.

After spreading it, I just wipe off the excess with a rag and voila, it’s done!

Yes, really done this time, after all of these steps.

All in all, I’m glad I did it because now this part of the hall looks finished. If I was starting from scratch, there’s no way I’d use Saltillo since I don’t like the look of it and it’s not fun to work with. But since it matches the existing tile and I had almost everything needed to do the job already, it was the clear choice. I’m gratified to see that it looks like the tiles have always been there.