# Replacing 2 ceramic tiles over Ditra



## RichardZ (Dec 19, 2011)

I had a professional tiler install ceramic tile in a couple of bathrooms in a condo unit I rent out. The old adage "You get what you pay for" applies in this situation. The guy was in a hurry (he had another job to go to), and so the tiles have varying degrees of lippage. Since it's a rental, I can live with most of it, except for a couple of tiles where the lippage is too much.

The floor consists of 10" joists, which have been variously reinforced with 2x12s laid flush between them (too much history to relate, but the result is pretty solid). Over this is a 1/2" subfloor (I know, it should have been 5/8" -- another long story). Over the subfloor is a second layer of 1/2" plywood (screwed in per JazMan's terrific instructions -- thanks JazMan!). Over this is Ditra. Ditra was used to put the finished floor right below the bottom of the toilet flange and to provide a measure of waterproofing (only the floor, not the walls, because a door provides plenty of exit for water should there be a significant tub overflow). Since the tile area is roughly 5'x5', Kerdi band was used where the two sheets of Ditra met.

I don't think the tiler was used to installing over Ditra. In any event, the Kerdi band appears to have been what caused the significant lippage. 

I took up the two most offending tiles. I now am faced with a layer of thinset over the Ditra.

It's been suggest that I take up the Ditra that was under the tiles. I don't want to do this, as it'd require buying a whole new roll of Ditra (yep, it came out pretty exactly right with the one roll). Also, I'm concerned about maintaining the waterproofing provided by the Ditra; if I replace the Ditra, I've got more seams.

Another person suggested just scrapping off what I could, and then using the thinnest layer of thinset needed to set the tiles. Will this work? If I use this approach, do I have to use the same brand of thinset (Mapei), or can I use another as long as it too is unmodified thinset (e.g., CBP - Custom Building Products carried by Home Depot)?

Another person said to use an adhesive remover like Sentinel's 747 Plus or a similar product from Henry's to remove all the thinset, and then lay new tile. Thoughts?

Lastly, there's the old mechanical approach (pound the thinset with a hammer to break it up, and use a putty knife to pry the thinset out of Ditra's rectangular holes). I'm not sure what effect this have. Will it damage the thinset under the Ditra which was used when the Ditra was laid down? Do I risk damaging the installation of the surrounding ceramic tiles? Other concerns?

Also, I have some small tears in the Ditra from when I was removing the tiles. Should I just cut the loose stuff away? Should I glue it back down with something like SikaBond? Other suggestions?

Finally, do I have to go back with thinset, or could I use a glue like SikaBond to install the new tiles? Yeah, unmodified thinset is cheap (6$ / 25 lb. bag), but I've never mixed any up, and while "it's easy", the less I have to screw up the better, especially since these tiles are smack dab in the middle of the floor.

Your help is greatly appreciated!

Richard


----------



## zakany (Sep 24, 2012)

RichardZ said:


> If I use this approach, do I have to use the same brand of thinset (Mapei), or can I use another as long as it too is unmodified thinset (e.g., CBP - Custom Building Products carried by Home Depot)?


JazMan will be able to answer your technical questions best, but I would recommend not using CustomBlend. The Schluter guys I talked to call this bagged dirt.

For unmodified thinset, I shop Lowes (it's usually Mapei or Megabond, depending on your area). For latex modified, I shop Home Depot. So for DITRA, I find myself going to both big box stores.


----------



## JazMan (Feb 17, 2007)

Richard,



Richard said:


> #1 It's been suggest that I take up the Ditra that was under the tiles. I don't want to do this, as it'd require buying a whole new roll of Ditra (yep, it came out pretty exactly right with the one roll). Also, I'm concerned about maintaining the waterproofing provided by the Ditra; if I replace the Ditra, I've got more seams.
> 
> #2 Another person suggested just scrapping off what I could, and then using the thinnest layer of thinset needed to set the tiles. Will this work? If I use this approach, do I have to use the same brand of thinset (Mapei), or can I use another as long as it too is unmodified thinset (e.g., CBP - Custom Building Products carried by Home Depot)?


I'd prefer to do #1 if you can get your hands on a little scrap. I wouldn't be concerned about waterproofing since you can't make the room waterproof unless you flash the walls and curb the doorway. Floors are not required to be waterproof. 

Your #2 method will work too being careful to remove all the thinset down to the Ditra. Use the same or any brand/type (even modified), of thinset except the cheapo Custom Blend you referred to. Do not buy any cheapo $6 stuff and do not use anything pre-mixed. 



Zakany said:


> CustomBlend. The Schluter guys I talked to call this bagged dirt.


That's a bit tough Zakany. It's actually one notch above dirt. :laughing:


Remove the thinset with a tool like this. http://www.google.com/imgres?q=craf...ndsp=44&ved=1t:429,r:10,s:0,i:130&tx=59&ty=52 



> Another person said to use an adhesive remover like Sentinel's 747 Plus or a similar product from Henry's to remove all the thinset, and then lay new tile. Thoughts?


This person has no clue.:yes:

Leave the small tears alone, they will not affect the uncoupling aspect.

Jaz


----------



## zakany (Sep 24, 2012)

Those weren't my words! At the time, I had _never _tiled anything. I was talking to a group of Schluter representatives at a home improvement show, learning, and they made sure to tell me to not use CustomBlend. (Engineers like me research the crap out of things before getting our hands dirty.) The only time I ever used CustomBlend was in a tiling class (again, before I was to tackle my first tile job at home). Learning with that stuff made the actual job with better materials that much easier.

A good homeowner selection for a modified thinset is Versabond (from HD) because, again hearsay, it's not _that _modified.

Adhesive remover might remove thinset if that thinset was the premixed stuff, which isn't thinset but is, instead, adhesive. Unfortunately (or, actually fortunately) Mapei isn't adhesive.

Oh, for mixing, here's what I do. Get a little bucket, clean but disposable. Pour some thinset powder in (you don't have to use the whole bag and you don't have to measure). No more than 1/4 full! Then pour in an insufficient amount of water and stir with a trowel. Then add water and stir a little at a time and what you're going for is something like pancake batter. Scoop some up on your trowel and hold it sideways. It should droop and stick, but come off if flicked into the bucket. If you mess up and add too much water, add more powder.

For such a small batch, I wouldn't bother with a drill motor and mixing paddle.

Yes, you will end up with an almost full bag of thinset left over from this job. It does have a useful shelf life, so it won't be much good several years down the road. Even better is a buddy with some leftover thinset. Free thinset is the best thinset.

For tears and loose patches of DITRA, I'd probably just ignore them. It's not going to matter if you get thinset beneath them as well as on top - that's how it's installed.


----------



## zakany (Sep 24, 2012)

Oh, when it comes time to grout, you'll use even less but you don't want pancake batter - you want peanut butter or cookie dough. You want to be able to make a ball of the stuff.

Again, I didn't measure. Just pour and stir, pour and stir until I got it right.


----------



## RichardZ (Dec 19, 2011)

JazMan,

As always, your help is a life saver.

Unfortunately, my Ditra scraps are just that: scraps. 

I think I'm going to try for option #2. Thanks for the link to the Sears MultiTool. I've had my eye on getting one for a while, as they seem quite versatile. BTW, do you have any experience using different versions of these tools? Since I'm pretty much always near an electrical outlet, I'm thinking of getting a corded one, just to have the max power available. I've seen the Sears one, as well one's from Dremel, Rigid, and Porter Cable. Any experience/thoughts on these or any other ones you've used?

Regarding the Ditra tears, they are kind of sticking up. Should I just push them down and mud over them, or cut away the parts that are sticking up?

In terms of thinset, Lowes carries Mapei, which is what the installer used. They have KeraFlor ($6) and KeraSet ($21). Any preference? I have only two tiles, so $6 looks a lot better than $21. On the other hand, I might be retiling the bathroom in my house. If the KeraSet is a lot better and it'll keep fine in a cool dry place, I'll get the KeraSet.

Finally, I noticed that you didn't say anything regarding the last option of hammering away. When I used a hammer in getting the two tiles out, did I possibly damage the integrity of the floor?

Thanks for your help!

Richard


----------



## ToolSeeker (Sep 19, 2012)

As far a Ditra goes probably if you ask a couple tile guys in your area they will give you a piece that big.


----------



## JazMan (Feb 17, 2007)

Richard,

Sorry you don't have much Ditra left. But you know you can use small pieces, makes no difference for a small repair. Otherwise I can bring you some in a year or two. :wink:

I recommend the corded version of those tools for most people. The best is probably the Fein Multitool, but $400-500. I bought the Craftsman and happy with it so far, (2-3 years). If you want a real cheapo, Harbor Freight has one for under $20, and on sale sometimes for $9.99. 

I can't imagine KeraSet would cost $21, are you sure? 



> Finally, I noticed that you didn't say anything regarding the last option of hammering away. When I used a hammer in getting the two tiles out, did I possibly damage the integrity of the floor?


I don't know how violent you got. 

Jaz


----------



## msaeger (Mar 1, 2011)

JazMan said:


> Richard,
> 
> Sorry you don't have much Ditra left. But you know you can use small pieces, makes no difference for a small repair. Otherwise I can bring you some in a year or two. :wink:
> 
> ...


I have a fein and it is great! They are only 200.00 now if you get on that only comes with a few attachments.


----------



## zakany (Sep 24, 2012)

Remember that you may not be limited to big box store selections for thinset. You may be able to find Laticrete or Bostik products in your area from other retailers.


----------



## RichardZ (Dec 19, 2011)

JazMan, 

Sorry to take so long to get back to you. 

Regarding the tears in the Ditra that are sticking up, should I cut them flush or glue them down?

Regarding the Mapei thinset prices, they came from Lowes.com. From your question, I called my local Lowes, and they said $11 for KeraSet -- much better. I take it that I should go with the KeraSet, unless you recommend another type/brand.

I did whale at the tile a bit. I guess I'll just have to live with whatever resulted. I'll say this, the Ditra sure appeared resilient -- hopefully, it did its isolation thing well.

I'm looking at the various multi-tools out there. I'm glad to hear that your Craftsman has held you in good stead. I'll look into it ...

Looking forward to hearing your advice on the Ditra tears ...

And, thanks!

Richard


----------



## RichardZ (Dec 19, 2011)

MSaeger,

Thanks for the heads up on Fein. Sears carries it, and I'll at least be able to take a look at it (altho the web may have better prices ...).

Richard


----------



## JazMan (Feb 17, 2007)

Richard,



> Regarding the tears in the Ditra that are sticking up, should I cut them flush or glue them down?


Yes you should. :wink: No need to glue small tears, just push them down or cut them off. It's still bonded right?

Use whatever thinset you can get. Makes no difference really.

Jaz


----------



## RichardZ (Dec 19, 2011)

JazMan,

Got it -- I'll take care of the tears.

BTW, any advice on actually installing the two tiles? The other tiles are kinda all over the place in terms if heights. Should I back butter the tiles? Add some extra at each of the four corners? Something else?

Thanks!

Richard


----------



## JazMan (Feb 17, 2007)

> BTW, any advice on actually installing the two tiles? _The other tiles are kinda all over the place in terms if heights._ Should I back butter the tiles? Add some extra at each of the four corners? Something else?


That's not so good. Spread thinset like before, yes back-butter. 

Jaz


----------



## RichardZ (Dec 19, 2011)

JazMan,

Yeah, the job that was done was not particularly great -- as I said at the beginning, you get what you pay for.

Thanks for the advice. Wish me luck as I embark on my first DIY tiling job -- I think I'm gonna need it!

I'll let you know how things turn out ...

Richard


----------



## RichardZ (Dec 19, 2011)

JazMan,

Remember when you asked if the Ditra was still bonded?

Well, I was double-checking everything, and I noticed that the Ditra was a little springy where the two sheets meet. I ran a knife along the seam, and lifted it a bit so I could squirt some glue in there, and the area just got bigger and bigger. The thinset is sticking to the Ditra, leaving the plywood pretty clean.

Can I vacuum out any debris, squirt some glue (I'm thinking SikaBond) in there, and then put a heavy weight on it (e.g., 5 gallon bucket of paint) until it dries?

Alternatively, can I cut out the Ditra, spread some glue, and then put it back down?

Some other alternative?!?

The best expression of my mood right now? Arrrrrrrrgh!:furious:

Thanks for your help,

Richard


----------



## JazMan (Feb 17, 2007)

Cut out the bad area and reinstall with thinset if it's a large area. What kind of thinset did you use to stick Ditra to the plywood? 

Jaz


----------



## RichardZ (Dec 19, 2011)

JazMan,

I'm not sure what thinset the tiler used -- I believe it was non-modified Mapei.

The area is about 4x12, maybe a bit larger, with the seam running through the middle of it. Are you saying I should cut the unbonded Ditra out on either side of the seam, coat the bottom with SikaBond, and put it back in place?

BTW, I've cleared the Ditra of all the old thinset -- it's as clean as a whistle. Almost looks like brand new Ditra, save for the various nicks from my digging the thinset out of the squares. (And yes, a bit of the anal combined with available time overpowering good sense ...)

Your help is greatly appreciated, JazMan.

Richard


----------



## JazMan (Feb 17, 2007)

If the right thinset was used to bond Ditra to plywood, (modified, not unmodified), but you had a couple of loose seams, I suppose squirting some glue would be ok. But then it sounded like the problem is worse than that. 

If Ditra was installed with unmodified thinset, it's not gonna stick very well. It all has to be replaced. You mentioned 4x12, but I'm not sure how much is loose. But the important part is to know which thinset was used. Guessing will not work for me. 

Now you say you cleaned the old thinset out of the Ditra. But I don't know what you mean. Is it still on the floor, mostly bonded, or rolled up waiting for to be reinstalled? 

Jaz


----------



## RichardZ (Dec 19, 2011)

JazMan,

Unfortunately, I don't know what type of thinset was used under the Ditra. In fact, I'm concerned that they may have used the same thinset to install the Ditra, and then the tile over the Ditra. I guess I could call the installer, but I'd like to avoid that ...

I'll take pictures to show the current state and post them so that you have a better idea of what things look like. I should have those for you tomorrow.

As always, thanks!

Richard


----------



## RichardZ (Dec 19, 2011)

JazMan,

Here are the promised photos. 

The one with my hand (#1358) is to show how far the lack of bonding goes. My thumb shows how far it stretchs horizontally; my other fingers show how far it goes vertically.

If you need more, just let me know.

Thanks,

Richard


----------



## RichardZ (Dec 19, 2011)

JazMan,

Just some additional info

#1358 is the one in the middle. 

On the right, the lack of bonding stops where you see the Ditra sticking up from the floor.

The lack of bonding runs in an arc from the left to the right, reaching a zenith vertically as indicated previously.

If you need more info, just let me know.

Thanks,

Richard


----------



## JazMan (Feb 17, 2007)

So cut it, peel it back and spread modified thinset and you're done. Then use the rest for the tiles.

I guess you don't know which thinset was used, but you're confirming the rest is stuck good....right? I would make the call. 

Jaz


----------



## RichardZ (Dec 19, 2011)

JazMan,

Thanks for the guidance. I'll cut out the Ditra.

I do have a few questions about putting it back down:

o Do I need to knock off the old thinset on the bottom of the Ditra?

o When I put the new thinset down, do I do a full 1/4" notch spread, or just trowel a very thin layer? 

o I understand from Schluter's installation instructions that I should use modified thinset to lay the Ditra, but unmodified thinset to lay the tile. As I understand your post, I should use modified thinset for both. Is my understanding correct? If not and I just need a thin layer to stick the Ditra back onto the plywood, could I use glue to put down the Ditra, and then I'd only have to buy one bag of thinset for laying the tile? (Hey, I do want to do the job right tho: if I've got to buy two bags, it's only a few dollars more, and I certainly can spend the extra $ to do the job right ...)

Sorry for all the questions. Next time, I'll hire you and then job will be done right the first time!!!

Richard


P.S. - No problem getting Mapei, even if I have to go a bit farther to get to Lowes. At the same time, somebody said when they needed modified thinset, they went to Home Depot to get VersaBond, a CBP product. A -- ahem! -- few posts suggested that CBP products were not particularly good quality (unflattering comparisons to dirt were made, I believe). Is VersaBond an exception? Thanks. Richard


----------



## JazMan (Feb 17, 2007)

Gently scrape or brush off what will easily come off, you don't want to remove much of the fleece.

Thinset for Ditra is not spread with a 1/4" square notch, use 1/4x3/16 V or similar. 

You can use modified to set the tiles too. I think we went over this earlier. Schluter recommends unmod for the tiles, but do you care or think they're gonna warranty this installation in any way? It's only a repair and must use modified under, so use it for the tiles too.

We weren't talking about Versabond when comparing the cheapo thinset to dirt. We we talking about Custom Blend $6 for #50 dir......ah..ah...thinset. Versabond is plenty good enough for most jobs.

Jaz


----------



## ToolSeeker (Sep 19, 2012)

Jaz quick question It looks like the thin set came off the ditra way to clean, whice makes me think they did use the wrong one. If this is true won,t the problem with the tile coming loose keep happening?


----------



## JazMan (Feb 17, 2007)

ToolSeeker said:


> Jaz quick question It looks like the thin set came off the ditra way to clean, whice makes me think they did use the wrong one. If this is true won,t the problem with the tile coming loose keep happening?


Richard must have worked at it for some time, I don't know how he took it off or how well it was applied in the first place. Either type of thinset would work to bond the tiles to Ditra. What we don't know is whether the right type was used to bond Ditra to the ply.

Jaz


----------



## RichardZ (Dec 19, 2011)

JazMan and ToolSeeker,

The tile was stuck down pretty well (it took quite a bit of effort to get it off), and the thinset on top of the Ditra stuck to to the Ditra pretty well too. About a third of the thinset came cleanly off the Ditra when I removed the tiles. The other two-thirds stuck stubbornly to the Ditra. It took me quite a bit of time to get it all off. I used a metal scraping knife. I'd stick a point in the middle of the square, keep digging at the thinset until it loosened up, and once a bit was loosened, the rest would come out relatively easily. Not difficult, but with so many squares, it was pretty tedious. I did a little bit each day, and finally got all the thinset out. Not having spare Ditra can make one desperate enough to do the seemingly stupidest things ...

JazMan, thanks for alerting me to the proper trowel. Question, if I use a 3/16" V notch trowel to install the old Ditra, do I risk having it go above the Ditra that's already on the floor, given that some of the old thinset will probably still be sticking to the underside of the Ditra? Does it matter?

Also, about modified vs. unmodified, the Schluter installation instructions say to use unmodified to set the tiles because otherwise you'll need to wait days and potentially months for the thinset to dry before you grout. If I use modified, how long should I wait before grouting?

Thanks,

Richard


P.S. - regarding the fleece, I understand your caution to me about it, having experienced it when I took up the Kerdi band. The fleece made dealing with the thinset under the Kerdi band an exercise in frustration. The thinset in the areas without the fleece wasn't particularly bad, but the fleece left over from the Kerdi band made removing the thinset underneath it 4x more difficult. In one sense, I appreciated what it lends to a proper installation. On the other hand, it my case, it was nasty stuff to deal with. Richard


----------



## JazMan (Feb 17, 2007)

You must use modified to install Ditra to ply. Since you now own some, go ahead and install the 2 tiles with the same. It'll work just super. :thumbsup:

A basic 3/16x1/4" V is usually enough, but it depends on how you hold it and how thick the thinset is. It's supposed to be thinner than normal, almost runny but will still hold the ridges when troweled. It's important, but not critical. You should apply less if there's still some thinset stuck to the back of Ditra. 

Normally the thinset adds no height to the installation of Ditra. Be sure to "beat" the Ditra into the mortar. I use a wood float, but smooth side of a trowel is fine.

You'll have no reason to wait longer before you grout, unless the big game is on.:laughing:

Jaz


----------



## RichardZ (Dec 19, 2011)

JazMan,

I finally got back to this. I cut out the Ditra, leaving about 3/4" inset from the surrounding tile, so that I'd have the edges of the old and new tile resting on the same piece of Ditra. 

Where the Ditra had puckered up, the plywood was as clean as a whistle. Elsewhere, the thinset had stuck to the plywood OK.

I looked at the Ditra I'd cut out and decided to toss it -- between the clinging thinset and damage, it wasn't worth keeping. The scraps I have could cover the cut out area, but it'd have to be done in three pieces. I took up the suggestion to call around and think I've found a place that'll give me a piece big enough for my needs.

I'm still nervous about putting down the Ditra with thinset. I know it's the right process, but I'm leery of my skills in pulling it off. Since this new Ditra will be inset from the edges of the tile and thus won't be supporting those edges but rather the "field" of the tile, can I use something else to secure the Ditra? Perhaps the ready mix adhesive they sell as a substitute for thinset? Glue? Construction spray-on adhesive (e.g., 3M "61" spray adhesive; I know it sounds a bit dumb, but this is a tiny area that'll be kept in place by the surrounding Ditra, and I'm pretty sure the 3M product will stick to plywood unlike the thinset)?

Thanks,

Richard


----------



## jeffnc (Apr 1, 2011)

RichardZ said:


> I'm still nervous about putting down the Ditra with thinset. I know it's the right process, but I'm leery of my skills in pulling it off. Since this new Ditra will be inset from the edges of the tile and thus won't be supporting those edges but rather the "field" of the tile, can I use something else to secure the Ditra?


I think you're overthinking this. I'm not exactly sure from your post what your concern is regarding "support", but it's not a big deal. Just watch a Schluter video showing how to lay Ditra. It's not very difficult and you don't have to have 100% coverage up to the millimeter. Anything that's missed will be filled in by thinset and even if it's not, that's where the grout goes anyway, right? Let's git 'r done. Once the Ditra is down, fill in all the waffle holes with thinset. Then you can back butter the tiles and use the trowel on the back side of the tile instead of on the floor. Put the tile down and press it down and see if the height against the other tiles is right. If too high, pull up the tile and retrowel to take a little of the thinset away. Otherwise, add a bit more. Common sense stuff.


----------



## drtbk4ever (Dec 29, 2008)

Richard, Do you have the proper thinset as per Schluter and Jazman? If so, trust that it will work. And you will do just fine. I'll go out on a limb and say that if you have the right thinset and trowel, the Ditra is almost idiot proof.

Not saying you are an idiot, sorry if it came off that way.


----------



## JazMan (Feb 17, 2007)

Richard,

You can use a single piece or pieces of Ditra that are an inch square, doesn't matter Ditra is not structural. Just cut the pieces to fit and stick em down. Use modified thinset *ONLY*. 3M spray adhesive? What?  



> pretty sure the 3M product will stick to plywood unlike the thinset)?


I don't know why the thinset didn't stick to the ply in that one spot. Do you think maybe you had anything to do with that? Modified thinset sticks to plywood just fine. 

Jaz


----------

