Can You Install Floor Tiles on a Wall?

by Roger


End of post.

Fine, I’ll elaborate . . .

To understand this you should understand what designates a particular tile as a ‘floor’ tile. A couple of different things determine this including the PEI Rating and Static Coefficient of Friction (that’s just fancy ass talk for how slippery a tile’s surface is).

Manufacturers do not necessarily determine the arbitrary term assigned to a certain tile, things such as a ‘floor’ tile. All they do is rate any particular tile following industry guidelines determined by the different institutions. In English that just means that the manufacturer doesn’t really call any particular tile a floor tile, they simply assign their tile the ratings.

Certain tiles are only called floor tiles because they meet certain criteria set forth by the different guidelines. For instance: if a tile has a PEI rating of 1 it is only suitable for walls and areas which do not receive foot traffic. This tile would not be called a floor tile.

If the same manufacturer creates a tile with a PEI rating of 3 along with a C.O.F. of 5 and a suitable Mohs scale number, etc., it may be ‘called’ a floor tile.

You can still put it on a wall. It will just be an extra durable wall.

Just about any 12 x 12 inch tile is commonly referred to as a ‘floor tile’ simply because of the size without taking any of the above into consideration. This is simply another example of misinformed dealers, stores, and installers. They don’t do it on purpose, it just happens to be common practice and they don’t know any better. Just because someone calls it a floor tile doesn’t mean that it is suitable for installation on a floor.  But I digress . . .

As long as a tile, no matter the size, meets a set criteria it will be suitable for your floor. It will also be suitable for your wall. This is also why you do not want to do it the other way around. You can use ‘floor’ tile on a wall but you cannot use ‘wall’ tile on a floor – it won’t last. It is simply not durable enough.

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We are using 1/2″ thick 2×4 tiles in 12×12 sheets for our backsplash. Our tiles just came in wooden crates with no instructions or specifications except “Studio Prima, Catamarca Green, 5×10 (cm) Mossaic”.

1) What notch size do you recommend on our trowel to get the proper thinset coverage?

2) Do you have any pointers for completely filling in the varying 1/16″ – 1/8″ spaces with grout?

3) They look like they’re marble, so would you recommend sealing them before grouting?

MJ :-|



Hi MJ,

1. 3/16″ u-notch.

2. When installing your grout install it at a 45 degree angle to the grout line in all directions.

3. They ‘look’ like marble, or they are marble? It makes a huge difference. If they are green marble you need to find out if it is a serpentine marble, if that’s the case it can not be set with regular thinset, it may curl (like warping wood – seriously). The manufacturer can tell you that, but you NEED to find out. If you don’t you may just be throwing money out the window if you set it with thinset, you may need to use epoxy setting material.



Thanks for the response! The tile store from whom we purchased the tile says they are marble but doesn’t know if they’re serpentine.

1) Can you tell serpentine marble just by looking?

They also have no contact information for the manufacturer (in Italy) and no further information about the tile! They suggested I use “regular” thinset, but now I’m a little worried.

They also suggested I might want to mix sanded and unsanded grout, but I don’t know if that was just an attempt to get me to buy TWO 10-pound bags of grout instead of one. I didn’t buy any from them.

2) What do you think about mixing sanded and unsanded? Is it worth doubling the cost?

Thanks, as always



Hi Roger,

We are working on a project and using porcelain 60*60 tiles for the wall in a tunnel. Now, we are using a system that we call it”scoping the tiles” which means using a wire in the back of the tiles for putting in a masonary.

Do you have any experiences about this case?

I also can send you the photo of the way we are wroking.



Tara Sylvestre

Hi Roger,
I have some beautiful ceramic tiles, 12×12 and 4×4, which were originally meant to be used for flooring. I am wondering if I could use them for a counter backsplash. They are 3/8″ thick. My worry is that the 12×12 tiles would be too heavy to wall mount. I would like to mount them two high.

I am also not certain how to deal with this thickness around electrical outlets. My plan had been to tile around the faceplate and just make it look as nice as possible but I am open to any other ideas.

Thanks, Tara



Hi Tara,

Yes, they can be used on the counter. The tile are not too heavy for a wall, just use thinset, they’ll be just fine. Remove the outlet covers, unscrew the outlets from the wall, tile, and reinstall the outlets with longer screws which allow the outlets to lay flush with the tile.



I found a 20×20 ceramic tile that I would like to use in a shower. It’s originally for floors- glazed, semi-smooth (sort of a fake slate texture). I’m concerned that it might be difficult to keep clean in the shower. Any thoughts?



Hi Trish,

Completely up to you how much maintenance you’re willing to provide with your shower tile, I can’t see it from here. :D Yes, it will require more, no it’s not a deal breaker at all. It just requires a bit more long-term work.




First and foremost… Thank God for you and your willingness to assists us do it yourselfer’s :)

My brother and I decided to take on the project of remodeling my master bathroom. We did alot of research regarding demolition of a shower/tub and converting it into a shower. In addition, we research the options relative to the shower pan and decided to go with a cumstom made preformed pan manufacturerd and sold by KBRS.

We feel we successfully managed to complete the subfloor preparation ( concrete slab with hardiback board on top as a substrate) Had a plumber reconfigure our drain, install and modify the height of a new valve and raise the shower head. We placed the drain and the preformed pan exactly per KBRS instructions, and then installed hardiback board on all walls per KBRS and manufacturers instructions. We then used Redguard to waterproof the entire shower stall area (2 coats). Of course we then thought we were homefree and on the easy road to tiling. NOT!! We neglected to do our homework on this one and now I think we have “screwed the pooch”.

We have 12 x 12 porcelin tiles set in polymer thinset motar, we apparently got cocky and thought we could do this part without any help. We have tiled the lower portion of the back wall, starting from the floor up and starting from the back left corner moving across the wall to the right. We also started both side walls starting from the floor up and from the back walls towards the curb, we now realize we are in trouble….. Imagine that! We did this all wrong. Nothing like Monday morning quarterbacking.

We started to notice that even though we checked to make sure all our walls were level and square at the pan, we neglected to think that the walls would not be square up top. Now there is a growing gap where the side wall meets the back wall and I fear we will have the same problem on the other side. We left only 1/8″ between the bottom wall tiles and the pan, so we can’t position the floor tiles underneath the wall tiles.

So my questions are:

1) Can we place the floor tiles so they butt up against the wall tiles and seal where they meet with 100% silicone caulk?

2) Do we just continue and do the best we can to make it look tolerable and live with our special “art” as a constant reminder of our over inflated ego’s?

3) Do we; can we; remove all the tiles and scrap off whatever thinset we can, redo those area’s of hardibacker with the redguard to waterproof and start tiling fresh.

4) Do you have any suggustions for us to help us out of our self created misery.

Any help you could give us would be greatly appreciated. I wish I had found you before I started this project.




Hi Cindy,

1. Yes.

2. Yes. :D You can always ‘grow’ the vertical grout lines as you go up the wall a little so the tiles will be at least closer to the corners.

3. That would be the best option. Start by centering either a grout line or a full tile on the back wall and cut as needed up the wall in the corner. Start both side walls AT THE CURB and tile back to the corner, cutting there as needed.

4. See number three. :D

And don’t feel too badly, it’s still a hell of a lot better than my first attempt. :D


robert e

Hi Roger
great site! I bought your ebooks too
I have a diy question:
I am remodeling a small corner shower. I used hardibacker then redguard on ceiling and walls and I have tiled the walls using 20×20 porcelain tiles. my intention was to tile the ceiling too but I found that it is 3/4″ out of level on one side and I would have an big unsightly diagonal gap on one side of the shower at the ceiling.
would it be wise to build up the thinset on the ceiling and try to level it off?
any ideas?



Hi Robert,

No, you can’t float out the ceiling with thinset. Ceilings are most always out of level, no one pays attention to them. If you have a cut tile at the ceiling (on the wall) then your best option is to remove the top row, install the ceiling, then cut the top row to it. If you have a full tile up there you don’t want to do that, you’ll have a sliver of tile filling in that gap. Honestly your best option at that point is to remove the ceiling above the shower, shim out the portion that is out of level, and reinstall the board.


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