Tile FAQ’s

The list below contains some of the most commonly asked questions I get about tile and installation methods. For each one I have included a (very) short answer.  I already have, or will have in the future, a post about every one of these. If that post already exists there will be a link at the end of the answer.

I will continue to add to this page as the questions come up. If you have a question just leave a comment at the bottom and I’ll include it on this page.

Just click on the question to view the answer.

Grout

What type of grout should I use for my tile?

It depends on the tile and the size of the grout lines. Read this: Using the correct type of grout

How large should my grout lines be?

It depends on the tile size and the look you want. Read this: How large should grout lines be?

Can I fill my cracking grout with more grout?

Maybe. Read this article for a more complete answer: Filling grout lines with more grout

Are there any “magic” products available to remove stains from your grout and tile?

No there are not. One of the closest things to magic that you can buy is oxygen bleach. It is not bleach! It's a slight misnomer. This is the main ingredient in products like oxyclean. It works very, very well to clean grout. More information: How to clean grout

Does grout help stabilize tile, hold them in place, or make them stick better?

No it does not. (Epoxy grout is different) Read this: Does grout stabilize tile?

Are tile, stone or grout waterproof?

No they are not. Read this: Is tile waterproof?

Can I install my tile without grout lines?

No, you should not. Read this: Tile with no grout

Miscellaneous

Can I install floor tiles on my shower walls?

Yes you can. Read this: Floor tiles on a wall

Sealers

Will sealing your tile and grout make it waterproof?

No! It absolutely will not.

Should I seal (or re-seal) my tile and grout?

If you would like it to be easier to clean then yes, you should.

Setting Materials

What should I use to set my tile?

It depends on where you are installing the tile. Read this: Proper setting materials for tile

Are mastic and pre-mixed “mortar” acceptable to install tile on a floor or in a shower?

No they are not. Read this: Proper setting materials for tile

Substrates

Does my floor have to be level before I install tile?

No it does not. Read this: Does my floor have to be level for tile?

Do I need a waterproof membrane for my shower walls?

Yes, a membrane of some sort is required. Read the article for the different types. Read this: Preparing a shower wall for tile

Can I simply stick tile to the drywall in my shower or the plywood on my floor?

You can but it won’t last – so no. Read this: Preparing a shower wall for tile or this: Installing backerboard for floor tile

Transitions

Should I use grout or caulk in the corners of my shower?

Technically? Caulk. Realistically? It depends. Read this: Caulk or grout in corners?

If you have any suggestions or questions please feel free to leave a comment.

Jill

Hi Roger,
First, you are awesome! Second, I hope I’m not wasting your time with my questions. Haven’t come across any posts yet.
I have torn out my walls to the studs. The tub’s back wall and end wall (away from the faucets) are on exterior walls. I have insulated those walls. The other wall will be backed up to a linen closet. I already have some plastic sheeting that is 2 mil. Can I double it before stapling it to the walls if I make sure to get it tight?
And, if I start my 1/2″ cement board above the lip of the tub, with a gap!! what about the space/walls under the tub? Do I cover that area with anything?

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Delena

Because of exterior door height issues, would it be ok to use some sort of self leveling agent on my kitchen subfloor, then backer board, and install tile on that? I want tile, but have no room for plywood. My previous tile cracked due to no backer board.

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Sheldon

Hi Roger,

Greetings from The Great White North. My question is about setting tile:

I have installed a complete Schluter shower system because we had an odd sized alcove to fit a shower into. Having tiled and grouted the floor. when I look at a couple of the walls, the centre of the wall is lower than the corners (by about 3/8″ ) because I cut the shower base down to fit the area. Just gobbing in grout to fill the gap doesn’t do it aesthetically of course. Should the bottom row of tiles be scribed to the floor? In your opinion, what is the best way to get a consistent line between floor and wall?

Thanks for an enlightening and entertaining website.

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Roger

Hi Sheldon,

Yes, the bottom row of tile should be scribed to the floor if the perimeter of the floor is not level. When you cut down schluter pans you need to cut each side evenly. So if you need to remove 4″ of the pan you should cut 2″ off each side. That will keep it level.

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Eric Bello

I’d like to make a large shower area with curved walls. I don’t think cement board will not make the bend without breaking. I’m pretty sure I can do it with drywall but would like to know if it’s safe to use regular gypsum board with a topical membrane? Thanks.
Eric

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Roger

Hi Eric,

Schluter kerdi is the only membrane approved for use over any type of gypsum product.

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Jill

Hi Roger!
First of all, I have three dogs running around and best not screw this tile job up cause I sure don’t want THREE dogs to burst into flames. That could get real messy!
I am removing old tile from my bathroom floor. There was no cement board under it, just the old particle board type stuff. That “stuff” is on top of 1/2 inch floor boards lain diagonally across the floor joists. I want to put hardibacker board down before I lay the new tile.
First question: Should I still use 1/2 inch hardibacker board or will 1/4 inch be okay for yet another layer?
Second question: Do I need to scrape all the old thinset off the particle board and have it perfectly level before I thinset for the hardibacker?
Thanks for your input and sorry if I’m a little long winded. I’m a southern girl and we like to talk.

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Roger

Hi Jill,

It would be best to put a layer of 1/2″, or at the very least 3/8″, plywood over those planks. You need to remove the particle board, it has no business anywhere beneath tile. As long as you talk I’ll type. :)

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Jill

Thanks for the input. Since I left you the message I did decide to take up the old stuff and start new.
I do have another question though. My tub I am putting back is cast iron with a porcelain finish. I’m changing the old bathtub only to a shower tiled with subway tile. (I watch too much Fixer Upper). I have torn out walls down to studs and am putting 1/2 inch cement board up. Do I need to put some type of moisture barrier behind board? And, how exactly do I put the board over the lip of the tub and still have it attach to the wall studs to form a level surface for tile?
Once again, thanks. I’m sure you have probably addressed this somewhere. I just haven’t come across it yet.

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Jill

I’m so sorry for wasting your time. I found your manuals about tiling showers with tubs.
In my defense, my head is about to explode with a cold, I feel like crap, my plumber will be back in a few days and I can’t get my husband off his tush to help. Poor me😕

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Daniel

Hi Roger,

Abosolutely great articles with a lot of information. I tend to confuse myself so I’ll lay out the situation.

Old tile, old back board, old shower pan removed.

Will need to replace subfloor plywood
Will need to cut and install new drain
I literally cut out the old shower pan around the drain (think it was a poured lead sealant?)

*It is a second floor shower with wooden floors

Thought process:
Lay new plywood (was not intending on laying backerboard on floor)
Cut, nail shower curb with KD 2×4, 3 high
Attach bottom drain to plywood (hole pre cut)
Lay down, staple plastic sheet (over curb also?)
Lay down, staple metal lathe (over curb also?)
Create pre slope (using deck mud?)
*any thinset going anywhere?
Allow to cure 24 hrs
Sand or grind down any rough spots
Chisel wall studs or use carboard shims
Lay shower pan liner, taping edges to walls 6″ and lay over curb
Cut hole in liner for top clamping drain, glue and bolt flange
Fold liner in corners
Cut and fold over shower pan
Water test overnight?
Install backerboard on walls per the norm (securing pan liner underneath bottom with nails?)
2xcoat aquadefense or red guard on walls
Pea gravel around drain for weep holes
Top with layer of deck mud and make flat towards drain with the necessary height **drain is in middle of shower with about 1.5′ around to the walls
Is it necessary to mud over the curb or can i just tile at this point?
Allow to cure 24 hrs
Proceed with tiling?
Will the weight of this be too much for the floor, would i need more floor support?

Sorry.. I know it’s a lot, but i feel like i have all the pieces of the puzzle (or most of them) i just need some help putting them in order. The curb issue has me spinning.

Many thanks in advance,

Dan

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Roger

Hi Dan,

Plastic sheet does not go over the curb.
Lath goes over the curb after you get your liner in, it holds it to the curb for mud to go over it.
You DO NOT screw or staple it through the liner.
No thinset anywhere under your top mud deck.
Yes, water test overnight.
Only use nails at the very top of the liner.
You need to mud over the curb, but you can do the tile on the shower floor first if you really want to.
No, the weight will not be too much for your floor.

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Dan

Awesome, that’s a big help. Thanks for the advice. Previous installation had no liner of any sorts under the fiberglass pan and it seems they tiled right onto the drywall, I’m sure well before the topical water sealant was a thing. Also, do you have a preference when it comes to red guard or aquadefense?

Thanks,

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Roger

I prefer hydroban. :D Actually they are all comparable. Any of them work just as well as the rest. Dealer’s choice.

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kelly

Hi Roger, Am I mistaken or does the topical liquid walls book tell me to tape and mud the corners on one page and not to do that on another? Thanks, Kelly

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kelly

Pg 34 and 45

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Roger

Hi Kelly,

It tells you to tape and mud the corners on page 34 (after filling the gap with silicone) and not to get mud in the corners on page 45 (that’s what the silicone is for). On the in-plane seams you want to fill the gap with thinset, then tape and mud over it. On the corners you want to fill the gap with silicone, then tape and mud over it. You don’t want thinset in the gap at the corners.

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Victor Luling

I read your Slate in shower warning, “DO NOT USE SLATE IN A SHOWER! EVER!” Could you help me out and give me some details? I’ve become handy laying slate on floors (with ditra, of course), not wet zones. We were going to use it on a shower but now, maybe not. What were the problems you encountered? Is Travertine something you’d use?

Also, since I’m asking, I noticed you don’t use the kerdi shower tray for your shower floors. Is that just preference, experience or both? That’s another one that I was going to use but now, maybe not.

Thanks,

Vic Luling

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Roger

Hi Vic,

The problem with slate in a shower is that most ‘slate’ you see is not actually real slate, it’s shale. Basically (really) compressed mud. Over time in wet areas, especially with running water, the slate will tend to shed (looks like mud is running off of it) and cleave (individual layers of the rock will peel away). If you get REAL slate (read EXPENSIVE – like this: http://tileartcenter.com/slate-master-bathroom-installation-in-erie ) then you can use it in showers with no issues. Travertine is fine in showers provided you are aware of the maintenance necessities of it.

The kerdi pans are just fine. I actually saw one tiled and have a forklift run over it (seriously) with no issues. The only reason I don’t use them is that I rarely build showers that are standard sizes.

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Heathers

Do you need to apply silicone around the perimeter of the kitchen where tile meets tilled skirting

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Roger

Hi Heathers,

Yes, if the tile butts against the base (skirting) rather than being under it then it needs to be siliconed.

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Dina Phillips

Sorry didn’t know if pictures went through.
Dina

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Roger

Hi Dina,

It doesn’t look as if there is any waterproofing in there either. The entire thing needs to be removed and built correctly. You can begin here: Creating a shower floor for tile.

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Dina Phillips

Hi Roger,
I was hoping that was not going to be what you said, but kind of knew it would need to be done. Thank you for the link and this time I’ll make sure it is done right.
Thanks again,
Dina

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Dina Phillips

Hi Roger,
Ohh where do I begin.? As I began cleaning the mold and mildew from my shower I noticed that some grout was missing from some of my glass tiles, mostly along the corners and that the floor tile grout was looking porous so I decided I would re-grout it myself. Google that! I did and began my project. As I used the shop vac to eat the grout dust, water also came up. Not good.
Realized that the project was too big for me to do. I have had a couple of tile guys over and am so confused what to do.
Short story long, the shower was installed with no slope so the water was not draining properly. Oh yea almost forgot to mention this shower is relatively new. Totally gutted and redid my bathroom in Oct. 2013.
So I removed my beautiful marble herringbone tile and the last picture is what I found. What should I do next to have this done properly?
I included a picture of under the step up…… it seems that it hits to wood under looks like mortar or concrete was used under too when I removed the tile from there. What should it look like?
Can I have someone do the pitch over what it there now or do they need to knock out the current flooring and start from lower down! Not sure what lies beneath. Do they also need to tear down some of the glass tile that meets the current floor?
I just want to do it correctly this time.
Help!
Thank you for any information.
Dina

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