The days of grabbing a three dollar bag of “thinset” and sticking floor tile right to the plywood in a bathroom are long gone (for professionals, anyway). For a proper tile installation you need a proper substrate. One of the most readily available are cement backerboards. These include products such as Hardiebacker, Durock, Fiberboard, wonderboard and a host of others.
When properly installed on your floor it is an ideal tile substrate for a quality and lasting installation. Notice I said typed “properly installed”? Laying them down on the floor and shooting drywall screws through them does not constitute proper installation.
Choose your weapon. I prefer Hardiebacker or Fiberboard. Whichever you choose make sure you get the proper thickness. With rare exception the 1/2″ variety would be the best choice simply because I like to overbuild stuff. With proper floor framing and deflection ratios, though, you can use 1/4″ to minimize height differences. This is not to say that 1/2″ adds significant sturdiness to your floor – it does not.
Dry fitting Backerboard on floor
You need to realize that cement backerboards, or just about any tile flooring substrate, does not add deflection stability to your floor. That is the up and down movement in your floor when you walk, jump, or use a pogo stick on your floor. The backerboards will not significantly diminish that movement. This needs to be addressed by adjusting your floor joists and framing – not by adding stuff on top of them. If your floor is bouncy without the backerboards it will still be bouncy with them.
Bouncy is not good for tile. (There’s a sentence I never thought I would say type.) I will, however, address deflection ratio in another post.
Start by ‘dry fitting’ all your pieces. This simply means cut and lay your pieces into the room without attaching them. Get all your pieces cut, holes cut out, and doorways undercut to fit and lay everything in there just like it will be when installed. This saves a load of time, mess, and headaches.
Backerboards dry fitted - notice gaps in seams
The joints in backerboards should be staggered. that just means that none of the seams should line up across the room and no four corners should be placed together. By staggering the seams you add strength to the installation simply by not having a significant weak point in the substrate.
You also want to leave 1/16 to 1/8 inch gap between each sheet – do not butt them together, and around the perimeter. If you butt them together you leave no room for expansion. The backerboard will not expand, but your walls will. If everything is butted tight and your wall expands into the room guess what happens. That’s right, your dog may burst into flames and no one wants that! It will also cause your floor to pop loose and possibly ‘tent’ or peak at the seams.
Beneath the backerboards you need thinset. Just about any thinset will work but you need to have it there. skipping this step virtually eliminates the purpose of preparing your substrate for tile – you may as well go grab that three dollar bag and start setting tile now. You need it – really.
Installing thinset beneath backerboards
Now that you have them all laid in there properly pick one side of the room to start on and pull a row out. You should only pull out one row at a time to place thinset beneath. That way you can replace them easier and in the proper position. If you pull out the entire room you may get to the last piece and discover everything has shifted 1/2″ and the last piece needs to be cut again. Not really a big deal but you won’t realize it until the backside of it is covered with thinset and you now need to pull it up, wipe the thinset off the wall from pulling it up, cut it, clean the thinset off your saw, snuff out the flames engulfing your dog (again), and replace it. It’s a bit easier just to pull one row at a time.
You need to trowel thinset onto your floor. I cannot overemphasize this (well, I could but you’d get sick of hearing it). This step is imperative for a proper tile installation. The thinset is not meant to ‘stick down’, adhere, or otherwise attach your backerboard to your subfloor. It is simply put in place to eliminate voids beneath your backerboard. Once laid into the thinset bed the floor becomes a solid, fully supported substrate for your tile – that’s what you want.
If you have an air pocket or some certain spot in your floor that is not level or flat with the surrounding area and you simply screw your backerboard onto it this will create a weak spot in your floor. Constantly stepping on that spot will, over time, loosen the screw and your floor will move.
When your floor moves your grout cracks. When your grout cracks your tile may become loose. When your tile becomes loose your tile may crack. When your tile cracks your dog will burst into flames – again. Put thinset beneath your backerboard. And put your dog out.
Installing thinset beneath backerboards
Once you have the area fully covered with thinset you can lay your backerboards into the bed of thinset and screw it down. DO NOT use drywall screws! Let me repeat that – THAT! Drywall screws are not made, nor are they sturdy enough for your flooring. You will either bust the heads of the screws off or be unable to countersink them into the backerboard. Hard to get a tile to lay flat over the head of a screw.
There are screws made specifically for cement backerboards. You should be able to find them at any hardware or big box store. They have grooves on the underside of the head which will dig into the backerboard and create its own ‘hole’ in which to countersink the head as it is screwed in. How cool is that? If you look closely at the photo you can see the ‘grooves’ beneath the head. They are more expensive than drywall screws – just so you know. But you need to use them.
Each manufacturer has their own specific spacing instructions for screwing down the backerboards – follow them – really. Some say every 12″ and some want every 6 – 8 inches. The board you use will determine the spacing. (And its right there on the sticker so don’t tell me you couldn’t find it.)
Start your screws in the center of the board and work out. This eliminates undue stresses on the boards. If you screw all the way around the outside and it is not perfectly flat you are going to have to release that pressure somewhere and it
Backerboard screw
won’t happen until you have all that pretty tile on top of it. Working from the center out eliminates that. It would probably never, ever be a problem but if you’re anything like me your installation would be the millionth one for that one in a million occurrence.
Backerboard placed into thinset and screwed down
Your floor is probably too thick (should be) for the backer screw to actually penetrate into the floor joist. If not, or just to be safe, do not place screws into the area above the floor joists. The plywood or chipboard which makes up your floor will expand and contract at a different rate and, more than likely, in different directions than your joists. If you screw your backer into the ply and into the joist six inches over it will cause inconsistent movement – no good. Do not screw your backerboard into your joists.
After I have all my floor down I will go back and double the screws around every seam. Just put another screw between every screw along the seams. It helps me sleep better at night.
The last thing you need to do is tape your seams. Get an ‘alkali resistant’ mesh tape – similar to drywall tape – and place it over all your seams in your floor. Then mix up some thinset and trowel it over the tape with the flat side of your trowel. Just like taping and mudding drywall. This will make your floor one large monolithic structure and lock it all together. You want alkali resistant tape so it will not break down due to chemicals present in most thinsets. I do not have photos of this because I do it as I set tile.
That’s it! Congratulations, you now have a perfect floor for your perfect tile installation. When installing floor tile – or any tile for that matter – the most important aspect of the installation is always the preparation. Everything beneath your tile is important, if any one aspect is done incorrectly it may compromise the integrity of your installation. Take your time and do it correctly, you will be much happier for it.
Now go put your dog out.
Hello Roger, I have a question about using cement board in the bathroom, we have to remove the toilet because its leaking and the ply wood is rotted, but just around the toilet, question is, can you use just cement board around the toilet instead of putting ply wood down too, I would hate in years to come that we have a leak and have to replace the floor again.
Hey Kathy,
You need to replace that with plywood. Cement backerboard adds absolutely no structural stability at all. It simply isn’t strong enough.
So…we have a basement that we are attempting to tile and are getting lots of conflicting info. We tore up carpet and have the concrete left; looks like it was painted and has a felt-like coating on the top. We bought some backer board (FiberRock) and were all ready to lay it down, then realized that backerboard screws most likely can’t be screwed into concrete! We can’t really afford the Ditra and we don’t want to tile right on the cement so is it still ok to use the backerboard over the concrete (we will put the thinset under it and screw it down with concrete screws). Have you (or anyone?) done this?
Thanks
Amanda
HI Amanda,
I have never done that nor have I ever spoken with anyone that has. It is simply not a proper application for backer board. If you can’t afford the ditra maybe you can go directly to the concrete with a high-quality mortar such as Ultraflex II or III. It is more expensive than normal thinset but it adds the ability for movement without cracking your tile or grout.
HI ROGER ,happy sunday just a quick question sir .u told me a while back to use 3/8 trowel for laying 12×12 marbel ,so i went to store but all they had was 3/8 tooth length with 1/4 in space between teeth . is this ok im wondering if it will make the tile sit higher cause i dont want it to be any higher than it has to be thx m8
Hey Chris,
The distance between the teeth will not affect the height of the thinset after installation significantly enough to make a difference. The difference in the finished product of the 3/8″ and 1/4″ distance is going to be less than 1/16″.
Hello Roger, I am using thin set + 1/4″ tooth trowel +1/4″ backer board + thin set + 1/4″ tooth trowel + 1/4″ tile will it add up to 1″ total thickness?
Hi Chaz,
Nope – 3/4″. The 1/4″ x 1/4″ trowel will leave a 1/8″ layer of thinset after the backer or tile is pressed into it.
hi roger,just wanted to say thx again for this awesome site and ask but one more question .im going to start tiling the wall soon and dont know which way to trowel the thinset horizontal or vertical lines . 12×12 marbel and 3/8 trowel regards m8, chris
Hey Chris,
It makes no difference at all as long as you trowel them all in the same direction. Once you get the tile up and pressed into the thinset you should have no lines behind the tile at all – so there won’t be a direction to it once installed anyway. Whichever is more comfortable for you.
Roger,
I am installing a wood fireplace insert in an existing brick fireplace.
The existing concrete hearth is 14″ out from the fire place but in order to meet the current building code you must have a fire resistance surface 18″ out from the fireplace opening.
My question is how would you suggest I tile over the existing concrete hearth and extend the tile over the existing hardwood floor to get the 18″ with out having differential settlement?? and cracking tile??
Would you use a cement board over the hearth and the hardwood to obtain a unified surface for the tile?? or remove some hardwood??
Thanks
Steve
Hi Steve,
The best option (only option, really) is to have one unified surface for the entire installation. The best way to do that is to remove hardwood out to where you need and either remove the existing concrete and create a new mud deck over the entire area or fill in where you removed the hardwood with concrete or deck mud and install a membrane such as ditra over the entire area. You really want to avoid going over the top of the hardwood if at all possible. It expands considerably more than anything else you have or will have there.
Roger – thanks for the light-hearted way of addressing important information. I’ve been researching a lot on how to do a “simple” project and getting more and more concerned with every page I visit. You gave me my confidence back. But now I want to ask a couple questions, so I hope you won’t burst my bubble…
Our house was built in late 90’s. We’re putting ceramic/porcelain 17.5 x 17.5 in the livingroom. The floor is currently carpet, which we will remove before installing the tile. I’m confident that there is 3/4 inch tongue and groove strand board underneath. Main question is, can I just put in 1/2 inch cement board over that and then the tile, or do I need to put plywood over that first? From the other areas we’ve done work – replaced one section in hardwood, and some other with new carpet – the subfloor seems sturdy and not bouncy. What do you think? My other concern is how much of a transition there will be between the other flooring and the ceramic. I don’t want to end up with a 1 inch step up onto the tile portion…
On a side note, other sites state to remove the baseboard before installation. While I understand the concept, my concern is that there are no doors/entryways between the livingroom and the adjacent rooms. So, if I remove the baseboard and install the tile, I’ll have to rip the bottom part off of the baseboard (I might as well light my dog(s) myself here), before I put it back down, to keep it even with the adjacent walls. The thought I had was to leave it in place and install the tile up to the baseboard, then just put 1/4 round, or shoe base, on at the finished floor level.
I’m honestly not an idiot, just have trouble getting my head around some things before I get my hands dirty.
OK, so in re-reading some of the other posts, I see that, yes, I will need to put down some plywood over the existing strand. Should I go with 3/8 or 1/2? I plan to use cement backer, probably 1/2 inch since it’s actually cheaper than 1/4 or 5/16, which doesn’t make sense, but that’s a whole different subject (I’m sure it has to do with supply and demand). That said, I did see some alternative to cement in the 1/4 inch range. It’s called “Green E-board”? Here is the info on it –
>>Green E-Board is a ceramic tile underlayment manufactured from magnesium oxide as its primary ingredient vs. Portland cement. This offers a better environmental alternative and upgrade to replace gypsum drywall and cement underlayment boards for floors and counter tops.<<
Ever hear of it or have any experience? It's roughly the same price as the 1/2 cement board, but definitely less than the 1/4 cement board. Don't know if it's worth it, but was thinking it might help with the height of the floor compared to the adjacent rooms, as I mentioned in my first post. If I went with this, I'd definitely go with the 1/2 inch plywood, and then this over it. If I go with the 3/8 plywood, I'd probably use 1/2 inch cement. But your opinion is worth more than what my brain is trying to sort out right now…
I still do have the other stuff from my first post though…
Hey Jeff,
Sorry, I answer question in the order in which they were received – you know, like the Vietnamese call centers.
The green E-board is good stuff from what I’ve read and heard. I’ve never used it but I’ve spoken with people about it. You can use the 1/2″ ply and the 1/4″ E-board. Make sure you put thinset beneath the layer of E-board to fully support it. Other than that you’re good to go.
THANKS for clearing the bits in my head. My dogs will be happy. Even though I do keep fire extinguishers handy, they still don’t like to be lit up…
Oh, so there are many questions in front of me or did Sparky finally develop a red face due to all my questions?
Ceci
HI Ceci,
I’ll be back in town tomorrow to catch up – patience grasshoppa! I actually do other stuff – I have three kids and a high-maintenance dog.
Oh, sorry, thought you were upset with all my questions since, you know, I can’t see where my questions are on the list. Good that you aren’t. Anyway, Roger, I would think you should know by now that I am super patient. Remember, now about 7 weeks or maybe longer, lost track, with the only bathroom in the house down to the studs, my house still looks like a Lowes’ outlet, and now no longer nippy, but actually darn cold using that hose in the basement as a “shower”. Here comes the topper, mommy then gives me a big scare and the issue ends up being an underwire bra. Yes, not heart problem, but an underwire bra problem which was not included in the original story told to the sick as a dog daughter. So, what were you saying about patience, Roger?
Make sure your kids get the flu shot. Have a feeling it’s going to be a nasty winter. Actually, make sure your saintly wife also gets the flu shot. No Roger, you don’t need one since you are part elf. Sorry, Sparky, no doggie flu shot as far as I know.
Ceci
Hey Jeff,
You need a minimum of 1 1/8″ total height, double layer of plywood above the joists. Above that you can use a thin membrane or backer like ditra or even 1/4″ hardibacker. But you do need that height above the joists.
1/4 round will work fine – just be sure to leave at least 1/8″ gap between the tile and baseboards for expansion purposes.
Roger – one other question. The guys at the tile “shop” told me to use a 3/8 x 3/8 x 3/8 trowel for my tile. The tile is 17.5 x 17.5. Should I use the 3/8 or is 1/4 x 1/4 x 1/4 OK as well? I don’t care either way, it’s just that I bought enough mortar for doing the tile with the 3/8 trowel before I saw your site. So now that I’m gonna do the Green E-boards as well, and need to set those on mortar, I just need to make sure I have enough. If I go down to the 1/4 trowel, I will have enough for the entire job, including the backer. If I stay with the 3/8, I’ll have to get more, so I just wanted to clarify. Or, should I use 1/4 for the backer, but stay with the 3/8 for the tile?
You’ll need to use the 3/8 with tiles that large. The 1/4 will be fine for the backer.
O Great and Wise One,
Thank you (again) for sharing your tiling expertise in my bath-remodel post a few months ago. And, no, DH and I have not yet begun that daunting project, having given in to our fear of living with 4 other people in a house with the only full bath out of commission for what will no doubt be a substantial length of time. By substantial, I mean even longer than my previous preposition-loaded sentence… which begs the question: should I be concerned with how many rules of grammar I’m breaking so cavalierly? But I digress.
Having moved on to other, more easily manageable projects (of which this c1943 house is chock full), I boldly approach your throne once again, more tile questions in hand. The back story is: I want tile in my entryway, but not the tile that currently occupies the space. No, I want new, prettier tile. Kinda like a middle-aged man in mid-life crisis (uh, not my husband… I don’t think), who wants a younger, prettier (and bigger/perkier-boobed) version of his wife. And I wouldn’t mind the accompanying Ferrari either, although I’ll take a pass on the gold chains and pinkie rings (that’s just downright gaudy).
More back story, in case your answer depends on relevant information: The entry is approximately 6.5’ (across the joists) x 7’ (parallel to the joists), and the current tile is 6”x6” with cut corners and 2” diamond-shaped inserts, all ceramic of unknown age and quality. And they contain hairline cracks, starting at approximately the center of the room in a jagged and broken “L” shape (1.5’ across and 3-3.5’ long +/-). The (sanded, I think) grout lines are narrow (1/8” maybe?) with gaps here and there. The subfloor is 3/4” t&g (diagonal), and I pulled up the floor grate to see 3/8” ply and 1/4” backer, so far as I can tell, what with the tiny lines on the tape measure being difficult to differentiate from one another, even with my glasses on. (Truthfully, I didn’t even try my glasses, since they’re for distance only.) I should also mention that there’s a 1/8” or so gap between the ply and backer (thinset not spread to the edges maybe?). One visible installation no-no that screams at me is the grout around the perimeter, which prompts another scream that there may very well be other, less visible problems with this installation.
Braving the cobwebs and potential errant arachnid, I went to the basement to obtain an accurate span measurement. The joists are 2×10 fir in what appears to be good quality (hardly any knots) and condition (no rot or anything that would compromise their strength), spaced 16”oc. John Bridge’s Deflecto-lator says a 14’ span is acceptable for ceramic, but a 14.5’ span is not. As luck (or lack thereof) would have it, my span is 14.25’.
Before I bug the John Bridge experts with questions about possible deflection deficiencies/remedies, I’d like to pick your impressive (if somewhat alcohol-addled) brain about your best guess as to what’s causing the tile cracks, lest my new entryway floor end up in a feature article or book about tiling disasters. Deflection issue? Uneven substrate? Lack of expansion gap? Moisture penetration (Chicago area)? Please work your elfin magic and make my floor tile-worthy. I beg you. Or at least tell me how to do it, my aversion to manual labor be damned. (Although elfin magic would have WAY more shock & awe value.) Think of this as an intervention and put down your adult beverage long enough to help me just say NO to (tile) crack(s). Please.
Cathy
Hi Cathy, just can’t get enough of me, can you?
You know I am one of those John Bridge experts, right? I’m TileArt1, I just don’t make it to that end of the forum very often, I’m busy arguing politics.
It sounds as if it’s a combination of inadequate substrate (needs a minimum of 1 1/8″ ply, especially over the diagonal t&g boards) and maybe no thinset beneath the backer? One way or another there is something not supporting your tile properly, and the lack of expansion at the perimeter doesn’t help. I would get rid of everything down to the t&g and install a 3/4″ layer of plywood, then either ditra or 1/4″ backer with thinset beneath it. That will give you more than enough support for the entry – your deflection is fine.
As far as grammar – you spelled grammar correctly and didn’t end the sentence with a preposition. Everything above that is just extra benefit – at least I can read yours.
Just don’t start using a load of hyphens in the middle of your run-on sentences – like I do.
Roger Darlin’, you’ve made me a happy woman… and you know I can’t get enough of you any more than I can get enough money, chocolate, or episodes of Hell’s Kitchen and Chef Ramsay. In fact, I was thinking how much I love you before realizing I was actually thinking of my husband. Then I was thinking I worship you before realizing I was really thinking of God. So I decided that you’re simply an infatuation and that I was merely dazzled and mesmerized by your pointy ears and bell-tipped, curly-toed booties (and hyphen-laden run-on sentences). And I must say those tights you wear don’t leave much to the imagination
Omigosh! How many of the Seven Deadly Sins have I just committed in this paragraph?? Let’s see… greed, gluttony, lust… and sloth, if you count the TV watching. But do they even apply to Protestants? Sweet Jesus, have mercy (and grant me escape from judgment via that back door)…
And, no, I was not aware of you on the JB forum (very clever disguise BTW), although I should have known.
So…. the whole elfin magic idea for getting my floor done is a no-go then? While I certainly do appreciate your sage advice, I thought perhaps you’d like to ratchet up your shock & awe quotient by sprinkling your elf dust (kinda like fairy dust – on steroids) and getting my subfloor up to par without my having to lift a finger. I mean, though simple in concept, your plan does seem like a fair bit of work, which is a four-letter word (OK, the ONLY four-letter word) that I try to keep out of my vocabulary (except as it pertains to DH, of course
). And I figured while you were at it, I’d have you magically create (and install) a tile from the images in my head that would complement the cheap harlot of a tile from HD that I’ve already selected for my kitchen, and which apparently prefers to work the corner on its own, without the competition of coordinating tiles (or even the aid of a pimp). And while I’m sympathetic to the plight of my castoff entry tile, the fact is that it knew from the day I moved in that 1) our relationship was short term; and 2) I have a wandering eye for tile. No promises made nor broken here.
As for my floor, I thought the 3/4” t&g and the 3/8” ply both counted toward the desired 1-1/8” requirement, but I will take your expert word on the matter and follow your recommendations.
All this verbosity just to say thank you, Roger. Really, it’s just my way of avoiding all the painting yet to be done. Do you have any elf dust for that perchance?
The t&g planks do not support in the same manner as a full sheet of plywood. Each seam in the planks is a weak spot. so you really should have a thicker layer over it than 3/8″. I’m still workin’ on that magic elfin wand thing, until then I still do manual labor. Sorry.
Now go paint!
Hello,
I have concrete slab floors with glued down vinyl flooring in the kitchen, in the living room 3/4″ plywood with 3/4″ solid plank wood flooring, I have about an 1 3/8″ difference where they meet, I would like to install travertine tile in the kitchen and would like them level. What would you recommend I use to build up the kitchen floor and does the vinyl need to be removed?
Thanks for the help.
Hey Robert,
Yes, the vinyl needs to be removed. Depending on the thickness of your travertine (I’m assuming 1/2″) you can use either self-leveling cement (SLC) up to about 5/8″ and the thinset beneath the tile will make up the difference, or you can use a good medium-bed mortar which can be built up to 1″, although that is the less attractive, and more expensive, option. You could also bond a 3/4″ layer of deck mud to the concrete and install directly to that.
Will the glue that is on the concrete from the vinyl flooring pose a problem? Will I have to grind off the glue, or can I nail down a sheet of lath to the concrete floor, then install the deck mud over it?
Yes, the glue will cause a problem. Since you’re putting deck mud over it, though, just get as much as you can off of it. It isn’t imperative that the mud bed be fully adhered to the concrete. Do not nail anything down to the concrete. The deck mud isn’t gonna go anywhere. In flooring applications we use wire lath to strengthen the mud bed, not to adhere it to the concrete. We use thinset for that. The lath, if you want to use it (I normally only use it in areas over 100 sq.ft. or so) is simply laid into the middle of the mud deck thickness.
I need some advice on applying tile to our new deck. Part of this space is over storage and therefore waterproofing needs to be done. Can you please help me with the correct procedure….ie backerboard first waterproofing membrane next or is it the other way around….There seems to be conflicting answers out there and I would appreciate clarification on the correct way to do this.
Hi Pauline,
It’s difficult to give you a proper procedure as I don’t know where you live nor how often you get freeze/thaw cycles. Here in Northern Colorado I build them with 1 1/2″ double layer of plywood, then backerboard with waterproofing over that. You also need to ensure that you have a proper slope for drainage, correct layering and overlaps from the structure at the edges, etc. I always have a topical membrane directly beneath the tile, that way no part of the substrate ever gets wet.
Roger,
I am planning on removing the bottom row of tile on the walls and replace it. I do not want to disturb or damage the tiles above the bottom row. What do you recommend to remove the tiles? I was thinking of something to cut the grout and start chiipping away at the tiles. I’m guessing I should not remove the cement behind the tiles, just remove the tiles.
Thanks for your great advise.
Robert
Hey Robert,
The most important thing you’ll need to do is scrape out all the grout between that row and the one above it. Once you do that you can pretty much pulverize the bottom row without damaging anything above it. The easiest way is to simply use a pry bar to pry the tile off. Keep in mind, however, that if properly installed your substrate will likely be destroyed in the process, you’ll need to rebuild or replace it as well.
Roger,
Thanks for all your advise. I was able to get the 3/4 plywood installed to raise and support the subfloor. Then Put down the 1.2 backerboard. That stuff sure is fun cutting :-) Wall tiles came out no problem, as they were moreor less glued in, and did not damage the substrate.
To correct the problem with height to thetoilet flange, I just cut the old toilet drain pipe out and installed new pipe and flange to the height of the backerboard.
It all looks great and ready for tile..
Thanks again.
Hi Roger,
I plan on tiling the outside corner of the tub where backerboard meets green sheet rock. The two materials weren’t exactly butted perfectly. Do you recommend using a metal,plastic, or paper corner bead over the corner? Or just load it up with mud and tile over it?
Thanks!
Howie
Hey Howie,
The best option would be to use fiberglass mesh tape and thinset to tape that corner, then tile over it.
Roger, one more thing for me, regarding the edge of the tile job. When I install my tile, it’ll be taller than my wood floor, which will be installed later. Eventually I’ll add the ramped wood strip when it is. So… for that edge that will eventually touch the ramped strip, do I need a metal strip along the tile edge or do something else to hold the grout in place til it dries?
I’m figuring I need the metal strip, then when the wood floor goes in, silicone between the metal and the ramped wood strip to cover wood expansion/contraction. And gap the wood strip at 1/8″?
A Schluter trim piece or something similar is always a good idea. You’re grout isn’t gonna go anywhere but it does help protect the edge of the tile. I normally use 1/16″ space between tile and wood and silicone it. That’s always been enough for me, but keep in mind that I live in Colorado so humidity will likely treat wood differently in high humidity areas.
Roger,
I’m back again, and ready to start the demolition on the floor. And again, great info on this site.
For a floor that is uneven, and using a self leveling cement, as you recommented, would you recommnend I add new plywood to the subfloor first, and then self leveling, and then backerboard, or add self leveling first, then new plywood and backerboard to bring the floor to the height I need? I’m just trying to figure out what would be the best way to level the floor with the self leveling cement. There are some areas (about 14″ diameter, that is out of level and the current tiles and cement have been cracking). The defect is big enough to feel and see the dips in the floor. If I’m screwing in subfloor or backerboard, will that hurt the self leveling cement if the screws pass through it?
Thanks again for all the great information.
Hey Robert,
Just install an additional layer of plywood and pour the SLC. The tile can be installed directly to that – no need for backer. You want to either use backerboard or SLC – not both. Make sure you use the primer for the SLC.
Hi Riger I removed the old tile and the 3/8″ plywood that it was on (25 year old house). The subfloor is 3/4″ OSB. So now I know that to do it right I need to use a backerboard rather than plywood. Even though the old tile was set very firmly to the plywood … I’d also like to make it as easy to remove in the future as possible (in case the next owner wants different flooring).
Would you recommend laying plywood under the backerboard? If so what thickness? And what thickness backerboard? I wanted to minimize the height difference between the new tile floor and existing wood floor (which were flush previously), so I was thinking 1/4″ plywood and 1/4″ backerboard. Does that seem reasonable? I’m told that the joists and OSB will support tiles, and there was only one tile that was cracked. it was at the edge and it looked like there wasn’t much mortar under it. All other tiles held up just fine.
You say to leave a gap between backerboards because the walls might expand. You also say that the backerboards won’t expand. Wouldn’t you just need a gap between the backerboard and the wall then? Why not butt the backerboards up against each other?
Do I wait for the thinset to dry before putting the backerboards on it? It seems like this is what I want since this will make for easier removal later.
How do I ensure an even thickness of thinset over 200 sq ft? Or, how much tolerance is allowed? First time laying tile
Thanks for your help with these newbie questions.
I’ll pretend I know what I’m talking about and hopefully answer part of of that for Roger.
The 1/4″ plywood won’t be enough to counter deflection, so you’ll you’ll need 1/2″ at least. I think I caught that Roger would go 5/8″. Then 1/4″ backer board. I have to do the same thing for the back door tile job I’m gonna start on, and I’m gonna put a wood strip along the edge of the tile to keep the edge from catching toes. My tiled front entryway had this done (by the previous owner) and I’ve never felt it was a nuisance.
I’m eager for Roger’s answer for butting the backer boards.
As for dry thinset, I believe it would defeat the purpose of letting it fill voids under the backer board. So I expect wet is needed. For even thickness, you have to get good at holding the trowel at the right angle consistently. But seeing as it’s meant to be squished down a bit when the tile is set, it doesn’t have to be precisely right. You can use a wide level to compare tile height across a few pieces. If no tile is sticking up more than its neighbor, and each tile is getting good contact with the thinset (thinset is covering entire underside of tile when you pull it up), then the job’s going well.
P.S. My thanks to Roger for covering a few questions I had before starting my first tile job! Course, if it goes well my wife wants me to redo that boring off-white tile by the front door. So maybe it shouldn’t go well…..
BINGO! Thanks DJ.
I would use 5/8 or 3/4 but rarely find diy’ers that will do that. The 1/4″ is what most are set on and I know I’m not gonna change their mind from here.
And – it’s better than nothing. I tell everyone once they do a tile job in their own house the wife owns them – get used to doing it!
Ohhhhhhhhhhhh, I am not set on anything as you know, that’s one of my problems, so you could change my mind and have changed my mind, but please set me straight here. Is it 1 1/8 total plywood or that 3/8 or 3/4 layer you just spoke of ? Please pick one and stick with it(insert smiley face). Since I am posting again, when one puts the top layer of plywood over the initial layer, does one put it perpendicular to the initial layer and does one have to stagger the hardieboard if the floor is only 5 feet by 5 feet? Would think if one tried to stagger it in such a small area, one would have to cut up some pretty small pieces of hardieboard and that doesn’t sound like fun or like something the tile guy sent by God would like to do.
Thank you,
Ceci
Oops, meant 5/8, not 3/8. Yes, was having one of those PCP moments when I posted that 3/8.
Ceci
You need a total of 1 1/8″ height above the floor joist – not sure which part is confusing. Always stagger the joints so you don’t have weak seams. Yes it sucks, yes it needs to be done.
Oh, I should have clarified that the wood strip would ramp down from the tile to the wood floor.
Roger, can you answer the part about butting backer boards to each other? Good/bad and why?
I did, in the response right below where you typed this.
Hey Jae,
I would recommend not installing tile with the pretext of ‘someone may want to change it’. If they decide not to change it then they are stuck with an installation that will not last long-term and they will have to change it eventually anyway. Anyone changing tile should be prepared to remove a properly installed installation. If not – they have no business installing tile. Don’t install anything planning to take it out.
1/4″ ply and 1/4″ backer will be fine provided you place thinset beneath the backer then screw it down. The gap between the backerboards gets filled with thinset and taped with alkali-resistant tape to create a monolithic structure – that’s the reason for those gaps. The gap around the perimeter is to compensate for wall movement. Place the backerboards into wet thinset. If you wait for it to cure you defeat the purpose and it will not fully support the backer.
Consistent thickness is achieved by using the same trowel and the same motion to comb the thinset over the entire area. Standard allowable tolerances are 1/8″ over 10′ and no more than 1/16″ over 2′.
Thanks for the help Roger and DJN.
And Roger, that reply that I should not worry about trying to make it easy to tear down later is exactly what I needed to hear.
Great job on this site. Your explanation is pretty clear and concise. I really enjoyed the reading. I do have a question regarding the backerboard. Here’s my delima-
House build 1968, master bathroom problems. Currently the tiled floor has become unstable and there are dips in the floor. I think the toliet leaked around its seal, causing the cement to crack, and possibly present water damage to the sub floor. Chunks of concrete are now dislodging around the cracks. Upon closer inspection, there appears to be about 1 3/4 inches of concrete and tile on top of the subfloor.
Please correct me if I’m wrong, but I think to fix the problem, I guess I will have to remove all the original concrete down to the bare subfloor. but how should I replace that much material? Should I use thinset first, then apply (1 or 2) 3/4 plywood boards on top of the thinset, and then more thinset under backerboard? Can backer board be stacked to take up for that 1 3/4 inches less the tile height? Or could I just use (1) 3/4 plywood directly on the original subfloor to strengthen and then add enough thinset to the top of the new subfloor to bring the backerboard up to the appropriate level?
I guess I’m trying to find a way to fill in the removed 1-3/4 inches of concrete and tile before putting on new 4″ square tile.
What about the wall tile floor molding pieces? I was thinking of just removing the 1/4 round tile and let it go straight to the floor so there’s no rounded edge at the bottom of the wall.
Thanks for the advise.
Hey Robert,
Ideally you should have another mud bed installed. It’s a specialized skill and one which i rarely find people who want to pay for it. Beyond that you can stack up as many layers of plywood (next best, and cheaper than stacking backer) to get up to where you need your backer to be, then install your backer and tile. You don’t really want to shim everything up with thinset. You can use a self-leveling cement, but that’s gonna get expensive going that deep. I’d stick with layers of plywood.
You can get rid of the molding, a square transition from floor to wall is normal now. Leave a 1/16″ gap there and silicone it. Do not have the wall tile directly against the floor tile – you need to allow for movement.
Hey Roger,
I am having this same problem except my mud bed appears to be 2.5″ thick. It was an inch and a half right next to the tub but then it drops another inch beyond that when you move beyond the tub base framing. Actually, the subfloor appears to be recessed about 1″ down into the floor joists if that makes sense? Was that common in the 60’s?
All I know is I became even more confused and scared when I saw it. Not at all like I was the first night I started hammering off the old tiles in the shower and ripping off the walls.
The breakdown is kind of like this; 1/4″ tile, some kind of thinset or glue, 2″ or so of old mortar, wire, felt then plywood. Again though, the plywood is down into the joist instead of on top of it. Please help, my wife’s looks of joy and words of praise have quickly turned into scowls and questions-like “What are you going to do now??” and “Do you know what you are doing??” I don’t think I can keep up the straight face and the “don’t worry about it” much longer. Thank you.
Hey Kinsley,
Yes, depressing the floor where tile will be installed was common in the 60’s. You have a full mud bed there and the easiest thing to do is simply chip off the tile and install tile right to it. It will last as long as you need it to. If you pull any chunks of it out with the tile you can fill it in with either deck mud or thinset.
If you want to remove the entire installation and start from the studs just layer plywood up to the height you need, install backerboard and tile away.
Hi Roger,
Where wall tile is placed around the room on the green sheetrock, is it ok to continue using versabond mortar or is a different product necessary?
My floor is approximately 60sq ft. with 12″ tiles and 1/8″ grout spacing. Would one bucket of spectralock (1A,1B,1C) be sufficient? I’m having a hard time finding their recommendation specs.
Last but not least! Currently there is no entrance door to the bathroom. Would you recommend putting the threshold in first then the door on top or cut and place the threshold in once the door is in?
As far as adhesion, half of the threshold (stone) will be on the bathroom sub-floor and half will be on the hardwood floor. I was thinking mortar for the sub-floor and possibly liquid nail to adhere to the hardwood? What says you?
Thanks again!
Howie
Thanks again!
Howie
Hey Howie,
Versabond will be fine for your walls. Spectalock is sold in ‘units’. One full unit does about 160 sqft of what you’re describing. There are four ‘mini units’ in one full unit. Most lowes sell mini units. You need two mini units or 1/2 full unit.
I would put the threshold in first. Then you’ll know what height you need to be at and whether or not the door needs to be cut. Thinset will stick to that hardwood as well as liquid nails so I’d just use thinset for the whole thing.
Roger,
I purchased flexbond specifically for backerboard seams and corners. Do you think this is overkill? Should I stick with regular versabond?
I’m ready to grout my floor. Is there a specific epoxy laticrete that you recommend?
Thanks again!
Howie
Hey Howie,
It’s a bit of overkill, but that never hurt anything. If you just want to use the versabond that will be fine as well. I prefer SpectraLOCK epoxy grout. It’s very easy to work with.
another question roger…when you screw down the backer board – do you screw it all the way down tight to the floor?
Yes, screw it down tightly to the subfloor.
thanks – the subfloor is flat and strong (it’s unfinished hardwood). should i use 1/4 or 1/2″ backer board?
You can use either – 1/2″ is better for most installations. If you have planks of unfinished hardwood you need to install an additional layer of plywood over the top of it. Individual planks move separately and will cause undue movement beneath your tile.
how far down do i screw the plywood? and is 1/4 inch plywood enough or 1/2 inch?
You screw everything down tight against the layer beneath it. 1/2″ plywood will bring the floor up to where you need it.
hey roger…it’s been a while and just wanted to say thanks for all the help. i laid down the hardiboard (thinsetted and screwed down) but instead of tiles, i decided to go with tongue/groove bamboo wood flooring (glue down method). i laid the floor down about a month ago and it’s holding up perfectly – really solid sound structure.
so even tho i didn’t go with the tiles, i still appreciate the help. the hardiboard gave me a solid subfloor to lay the bamboo down. thanks again.
You’re very welcome DJ.
Good site..thanks. Been reading and reading… Cats have yet to combust though it has been close a few times.
Continuing on in the same vein..flat floor. We had a contractor add a dormer and take our open 2nd floor and divide it into 3 bedrooms, closets and a nice size bathroom. House built in the ’30s when a 2×4 was a 2×4, the subfloor is at least an inch thick and the hardwood floors are not veneer…and the house is far from square (polygonical?).
We are finishing the bathroom. The bathroom used to be a closet. The floor in the new “roughed in” bathroom is made up of maple planks, with one area that was routed out to accommodate a sill for the old closet wall..about 3/8″ deep and 4′ long. Another area is also ‘recessed’ as the floor had to be cutaway so as to install the soil pipe for the toilet. That has been filled with plywood but, again, an approx. 3/8″ recess (and about 2′ square) below the surface of the maple planks.
The current bathroom floor is even with the hallway floor.
Q1: How do I install 1/4″ plywood over the planks (as mentioned above) and fill in those recesses?
Also, once the 1/2″ backerboard (which I bought thinking I was going to install that on the maple planks) is installed I will need stairs from the hallway into the bathroom.
Q2: How to handle this transition?
Thanks in advance!
Hey Jim,
Just screw the 1/4″ to the planks only (not through the joists). The areas that are recessed can be filled with thinset, once cured it will fully support those areas. Then more thinset, then backerboard. Schluter, as well as a couple other companies, make a stairnose transition for tile. Just google “tile stairnose”. That or a custom piece of oak up and over the edge of the stair, then tile up to it, are the only two viable solutions for stairs I have found that last.
Hi Roger,
What size grooved trowel is best to lay mortar for 1/4″ floor backerboard?
Is it ok to tile the floor on the same day as laying the floor backerboard or would you recommend waiting 24hrs ?
Thanks for all the great tips!
Hey Howie,
I normally use a 1/4″ x 1/4″ U-notched trowel. If the floor is uneven or has dips in it, etc. use a 3/8″ instead. Once you get that backer screwed down you can lay tile right away, no need to wait.
I’m back again, Roger! My sister wants to tile the floor in her tiny basement bathroom. Under her vinyl flooring is just a concrete slab (nice and flat). I saw your post to Shawna that you think some membrane should be over the concrete. What type of membrane are you talking about? So it’s not recommended to just tile directly onto the concrete floor?
Thanks so much!
Hey Renea,
I normally use ditra over concrete. I serves several purposes, one being crack isolation. That means when (it’s never if – it’s always when) your concrete cracks it will not transfer up through the tile. If you tile directly to the concrete the tile will normally do everything the concrete does, that includes moving and cracking.
hey man – great site. i am doing my first major renovation on my own now – my kitchen.
i have everything basically out of the kitchen right now so my next step is re-tiling.
the floor has a layer of really thin stick-on vinyl tile. not sure if it was self adhesive or glued down (is there a way to tell?). the tile is no more than 1/16th thick – they are like really thin. and under that is an unfinished hardwood floor. i think they were glued on b/c i can see some residue on the hardwood where i removed a tile in the corner.
can i lay down the thinset right on top of this vinyl tile since it’s so thin and then screw down my backerboard over it or do i need to pull up all the tiles first, then lay down the thinset over the unfinished hardwood?
(i am going to be installing ceramic tile)
thanks for the help and this is a great service you are providing.
Hey Djsunyc (If that is your real name…),
Yes, as long as you install thinset beneath your backerboard and screw the piss out of it you’ll be fine.
thanks roger. my real name is deuce bigelow but i can not legally go by it b/c of the movie.
again, great site and very informative.
i pulled up some of the tiles and it looks like they were glued down. can i thinset over the adhesive or do i need to scrape all that nonsense up?
You can thinset right over that. The thinset beneath backer is only there for support, it actually doesn’t need to stick to anything.
Question on sub floor “upgrade”….
As others have said, an excellent site with excellent content. I have a second floor condo bathroom constructed in late 1960’s that I am gutting and rebuilding. Tiles going down on the floor are 13×13 which will be installed in overlapping brick pattern.
I pulled up a 1/2 inch layer of OSB (like) sheet which had sheet flooring glued to it. What is left is one layer of 3/4 inch planks nailed 16” on center to the floor joists. I will be adding some ring nails and screws since the planks are loose. I have 1/2 inch Durarock with thinset ready to go down on the floor but I think I need another layer of plywood before the “rock” goes down. I was thinking of gluing and screwing that plywood. Do you think that will be enough for the subfloor?
Thanks for the help.
Chris
Hey Chris,
You do need another layer of at least 1/2″ ply (5/8″ or 3/4″ would be better) but no need to glue it. Just screw it into the planks below and do not screw it into the joists – only the planks. Then the durarock and tile you should be good to go.
Thank you Roger.
Chris H.
I can’t find your reply to that question of mine re. the plywood so just chose a random reply of yours. You know don’t like doing that, but I’ve looked and looked and can’t find it. Yes, again, I know you will get it either way, but remember I am anal about it since think it helps others to better follow and understand. OK, back on topic, the plywood. I think I read somewhere that a space is also left between them? Yes or no? Does one also leave a gap where the plywood would meet the lower part of the frame of the room? If yes to both, does one fill those gaps with anything? Also, when one puts in the second layer of plywood, does one lay it any special way? Roger, look on the bright side, have finally moved out of the shower part with these questions of mine. Be happy.
Thanks,
Ceci
A gap is left between the seams of the plywood to compensate for expansion and contraction. Nothing is placed in those spaces If by ‘frame of the room’ you are referring to the flooring joists then no, you do not leave any gaps beneath the plywood. All your flooring layers need to be fully supported – gaps negate that.
Darn, there is no gap now. So, what size gap? Regarding the second part. I know no gaps beneath the plywood, but I am talking about the perimeter of the plywood. Does one leave a gap there? The plywood floor now butts against this piece of wood that is horizontally oriented(3 1/2 inches deep and 1 inch wide), don’t think it would be considered a floor joist, that is part of the frame of the room. Maybe it would be considered a stud that runs horizontally. Think of a box(“frame of a room”). Hope that was clearer. So, any gap there? If yes, what size gap?
Thanks,
Ceci
Always leave about 1/8″ between any pieces of wood meeting. Never butt them.
Hey, Roger, I found the proper word for that piece of wood, I think, that makes up the frame of the wall that I have been trying to explain. I think it is called a lower wall plate/base plate/floor plate. It’s that number 6 in the pic.. Hope that clears up your confusion :)) and :))
http://en.wikipedia.org/wiki/Wall_plate
Thanks,
Ceci
hi roger, chris again sir, just wanted ur thoughts on molding . the floor is marbel as are the walls there is a 3/8 gap between them .caulked is it ok to glue moulding to tile and any preference to molding material there is no shower in the bathroom thx CB
Hey Chris,
I usually don’t install any type of molding when wall tile meets the floor – no real reason to. No type of glue, short of epoxy, will attach molding to marble long-term. The only idea I would have would be some type of ceramic molding attached with epoxy setting material.
“If you would like to forego the additional plywood you can eliminate the 1/4″ fiberock and use DitraXL over the current plywood – it’s rated for a single layer of plywood.” -Roger
Hi Roger,
I have a house built in the 80s. I am planning on tiling my upstairs bathroom with 13×13 tile. (I knew there had been a leak from the sink before I bought the house. When we pulled out the vanity and then the vinyl, we found a bit of a mess as someone had put 5/8 inch chipboard under the half of the floor near the sink (which as stated had leaked sometime after that so it was severely damaged.) The other half (around the toilet area) had 5/8 plywood on top of the subfloor. We tore out the section of particle board and found the original subfloor in good shape. It looks like it is OSB… The carpet in the adjacent room is on top of the OSB subfloor so we don’t want to raise the bathroom floor too much. We were thinking we would have to tear out the section of 5/8 plywood and replace with a thinner layer of plywood and then the rock board and tile. I saw your comment above in reply to Shang, which said Ditra would work over the existing 3/4 plywood subfloor as it is rated for single ply. I have also read in many places not to install tile over “chipboard” so I don’t know where we rate OSB in this area. (do we rate it as a sturdier “chipboard” or more as plywood?)
I would love to use the DITRA to keep the floor height to a minimum and because I’ve heard it is really good stuff. The thing is I want it done right but cost is in play as well. While I can justify the price of the DITRA if it cuts out the cost of both new plywood and rockboard (and all that), I can’t really justify it if I have to buy all new plywood anyway….so getting to my actual question…. Can I put DITRA right over the original OSB subfloor or does it have to go over standard plywood?
Hi Shawna,
The statement you’ve quoted is not ditra – it’s ditra XL, a different, more expensive type of ditra. And it can’t be adhered to OSB anyway – only plywood. The best you’ll be able to do given your floor is an additional layer of 1/2″ ply and 1/4″ backerboard or 1/2″ ply and ditra. Sorry.
Yeah, I found the information about the XL on Schluter’s website after I posted this. Although their website does say the XL can be used directly on OSB, I still didn’t think this was a good idea from all that I’ve read. We decided to just stick with the plan of plywood and backerboard. Thanks for the prompt reply!
Hi Roger,
We have everything for the bathroom so I’m hoping we can get all that done soon! I am also replacing the coutertops in the kitchen and have been tossing around the thought of pulling the cabinets and tiling that while it’s tore up anyway….I also have a small bathroom downstairs that I am planning on tiling as well. I was just wondering about your thoughts on tiling over concrete…. I have read a lot (actual very little as most sites only talk about wood floors) of contradictory information on tiling over a concrete slab…. The whole downstairs is on a slab. It is an old slab (as I said 80s) and is very flat…. I’ve read that on a good older slab that has already done it’s settling that you don’t need backerboard. Some say you do. I even saw some post a while back that said 1/2 backerboard for concrete and 1/4 for wood, but most everywhere else says 1/2 is just for walls…. What is your take on this?
Hey Shawna,
My take on it is that there is no proper, nor accepted, manner in which to adhere backerboard to concrete for tile installation. It’s simply not possible. I always prefer a membrane over concrete but it needs to be a sheet-type or liquid membrane which can be effectively installed on concrete.