I am so confused about tile underlayment
I know there have been a lot of threads on this topic already – I think I have read them all. But I feel like my situation is just a little unique.
I am gearing up to install about 900 square feet of travertine in a kitchen and hallway.
I have a TJI 230 floor 19.2 OC with advantech 3/4 inch osb sheathing glued and screwed. The span at the longest point is only 11 feet.
I have learned that the consensus is that the floor under the tile has to be 1.25 inches or more. And I of course want to do everything I can to ensure a long lasting installation.
The complication is that I am trying to keep the tile which itself is 1/2 inch thick similar in height to the adjacent hardwood (3/4 inch).
The simplest thing to do without the thickness difference would be to use 1/2 inch ply and then ditra then tile, but that is just too thick.
The best compromise I have come up with is to glue and screw 3/8″ plywood to the OSB followed by the thinset and tile, which would make the tile only 1/8 to 3/16 higher than the wood, a difference I can live with.
Is this going to be a sufficient structure under the travertine?
I am a trim carpenter not a tile installer, so I am a little out of my league here.
Sorry for the long post and thanks in advance for the help.
Jeff
Replies
Bump.
Thinset down 5/16 durock, and start tiling.
That is my 2 cents, I will be reading to see what others advise as I too have some tile work to do and am not a full time tile guy.
Webby
Durock is NOT structural...
better with 3/8" BCX and tile directly to that.A La Carte Government funding... the real democracy.
That is my 2 cents, I will be reading to see what others advise as I too have some tile work to do and am not a full time tile guy.
stop giving advice on things with which you have absolutely no working knowledge of.
Jeff Buck Construction
Artistry In Carpentry
Pittsburgh Pa
Sorry, I should have said that I have done tile work but my expereince is definitely limited to stock materials on various renos that my boss and I have done. Mainly porcelain tiles which our clients most often choose.
I am interested in gaining knowledgeable advice here from this discussion regarding the non porcelain tile i.e. travertine. I have a small area to do with granite tiles in the future.
If you will look back to my original post it was an effort to bump the OP's thread. Perhaps I should have left my other comment out.
I have also learned from this discussion thanks to EricPaulson and Sunsen.
Webby
Edited 1/3/2009 10:00 am ET by webby
Don't let Buck get ya tilted..............stick aroung here long enough you'll see that just how he is.
You might even grow to like him as one or two of us have............snork!
Thanks, I probably should have been more clear. I did however, take notice of what time it was when he posted.... grin!!
Webby
Edited 1/3/2009 12:13 pm ET by webby
<rant>Well, to my thinking, this was a poorly-executed design decision. If the floor is to recieve tile, and the design defined the tile area, then the floor design should have taken the need for subfloor thickness into consideration.
But, sadly, this seems to be "somebody else's problem" and remains invisible to those specifying out floors. I suppose if the kitchen were to have sheet goods, then the flooring installer would then also put down some 5/8" material to keep the floors relatively trip free?</rant>
Since you are dealing with the house as built, and tile will want a lot of subffloor, you have only two real options. Either the tile will be taller than the wood floor; or the subfloor has to be built down into the between joist spaces.
The other choice is to try some form of "thin" answer, with all the risks that entails.
Who specified the travertine? How do they feel about this? Trip or grout cracks--they are paying for one or the other.
But, I'm the answer to "What clown screwed up the flooring like this?" most of the time, anyway.
Well, I'm not a tile guy either, but I am a general contractor. I'd never let my tile guys do thinset directly on plywood. The thinnest application I've ever used is 1/4 hardi-backer, glued, (with one of those uerathane floor adhesives spread with a notched trowel), and screwed on 1 1/8" plywood subfloor. No problems with that installation whatsoever. Mostly we build up adjacent floors throughout to varying heights to achieve a uniform finish floor height.
Well first of all I admit I am not a tile guy.
But it seems to me that alot of this is buildup stuff is just overkill.
I have watched the guy I work for tile several floors. One of which was absouletly frightful. 1/2 inch ply that acted like 3/8. we thinset down 1 /2 inch durock and hit it with the roofing gun, every six inches. Then laid 12x12 3/8 porcelain tile on it. To my knowledge it is fine.
I understand the desire to eliminate deflection but isn't there a difference between practically eliminating deflection and eliminating all possibility for deflection?
I mean where does it stop. why not add some 3/4 ply to the subfloor, and go beneth and add some 1/2 inch ply and glue both with some good Pl adhesive, that gets you to 2 inch which is more than the 1 and1/2 inch mud bed thickness. Then some thinset and durock and then some tile. If the subject of floor hieghts comes up, just tell the client that the floor should have been built for tile, and this should have been addressed when the house was built, and while the floor will be higher, this is not your fault... and you don't want to give the customer a poor job.... er? Why mess with anything else at all and just go back to mud beds.
Allright maybe that is overkill, but doesn't the tile account for something in this. The OP didn't say what size travertine he is putting down. On 16 centers (I know the OP's is different) the actual span is more like 14 and 1/2 doesn't that factor in?
It seems to me the skill of the remodeler has to enter in to a large degree here. When an expereinced remodeler looks at a job that might involve tile and floor heights, and after evaluating the subfloor, can experience not be a guide as to finding an underlay that will give the customer the tile they want, while providing a reasonably long lasting install, and at the same time approaching a compromise with floor hieghts?
All I know is I don't want to have to demo the glued and screwed ply underlayment /subfloor at the next tile replacement job.
I hope my point is coming thru here. If so Learn me something new.Webby
HUGE differnece between Traventine and porcelain tile.
HUGE.
Okay, so the larger the tile the stiffer the subfloor must be. Good to know.
I was approaching it from the standpoint of the larger the tile, the more weight dispersal function it would afford.
I am assuming that a tile installation is a combination of parts that must be unified to work as one, i.e. subfloor, thinset, underlayment, mechanical fastener, thinset, tile. When unified wouldn't the tile take up some of the weight dispersion of traffic and furnishings etc?Webby
You are correct to a point.
You could drive a bulldozer over much of the porcelain out there. Ever try cutting or drilling it?
Travertine may fall apart as you lift it out of the box.
So with one you 'might' be able to skip a bit on the lower layers while with the other you need a good solid base.
Edited 1/2/2009 9:05 pm ET by EricPaulson
Okay, much of what we put down for clients is porcelain.
My boss will be putting some travertine in his home soon. It will be interesting to see how it works. Just 6x6 iirc.Webby
Deflection is a major issue with tile. I've seen natural stone tiles set on 4" thick concrete slabs run through with rebar break along what look to be surface cracks in the concrete. If you have any appreciable deflection you're going to have cracking. Especially with travertine. This is my direct experience.
If the fellow who started this thread uses thinset on top of strand board he is going to be extremely unhappy.
Also, on high end homes, all the floors are built to the same finish height, whether by cutting joists, (which can't be done in this fellow's case on account of he has TJI's), or adding underlayment. That's just the way it's done. However, there are rare occasions when a remodel can be a different deal.
Second. If you've ever had to take tile up off of OSB, you would agree with sunsen. Makes for an easy day, though! I ususally subscribe to the wisdom that the harder it is to take upart, the better built it is!
I think you're more likely to get a 1/4" difference between the hardwood and tile (3/8" plywood + 1/8" thinset + 1/2" tile).
What size tile are you installing ? The bigger the tile, the stiffer the subfloor will have to be.
How many locations and linear feet will you have tile adjacent to hardwood ?
If it's not too much and you have more than 1/4" difference, you could just put a transition piece over the hardwood. I made my own transition piece by using a board of the same hardwood floor and cutting it at an angle. It was 3.5" wide by 1/2" at the high side and 1/8" on the low side.
Edited 1/2/2009 8:31 pm ET by Chucky
The tile will be a versailles pattern, 24X16 16X16 16X8 8X8, so pretty large.I am a project manager for a production home builder, this is my own house, and honestly a lot of the things that I am trying to do are a lot more complex and demanding than the things I am accustomed to in the cheaper homes I build day after day.I never realized that travertine was so stringent in its needs for subfloor and now the stuff is already on order, plus I'm pretty set on the material. I had also considered using more plywood under the adjacent hardwood, but thats 600 more square feet, but if thats what it takes... Transition strips are what I am trying to avoid as most of the premade ones I see are typically so tall they look out of place. I hadn't thought about fabricating my own though.Thanks
jeffah,
Don't listen to anyone that tells you not to thinset over plywood. They do not have any experience doing so and are afraid to try it because they were told not to.
The ply build up is better by far than using hardi or cement board as long as you use modified thinset.
As for the transitions, any good flooring supply house should have hearth strip that is about 3/8 thick to almost 0 over 1 1/2". I am assuming you are using oak.
If not it is real easy to make your own.
In the meanwhile do an exercise.
Walk around your house from room to room through the arches and doors.
You will begin to notice if you pay not too close attention that when walking through either an arch or a doorway that you step over the imaginary line that would connect the two sides of the arch or the door.
The big question here is that with your joists and span, have you done your deflection homework to satisfy your tile installation needs? Go to johnbridges.com and look for the deflectometer.
Thanks for the input, the only number for calculating acceptable floor deflection I know of is L/360. I will check that website to see how to actually use that formula.
I have a TCA manual here.
If you want to email me your specs I will try to look them up for you.
I may log off soon so you may have to wait till tomorrow.
Here's the deflecto-meterhttp://www.johnbridge.com/vbulletin/deflecto.pl'Man who say it cannot be done should not interrupt man doing it' ~ Chinese proverb
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Thanks for the link. Unfortunately it says it does not work for engineered joists. But it did provide some useful information that natural stone requires a deflection of L/720 or less, the L/360 i had in my head was for porcelain tile.From the information in this thread it seems that I may be better off doing a 1/2 inch bcx ply with good pl adhesive then thinset and tile. which would give me an acceptable subfloor thickness of 1.25 inches and a tile that would sit only about 3/8 above the hardwood.
Post your question over on their forum, too. Lots of good tile info there. Somebody there should be able to give you a quick answer on your engineered joists, also.'Man who say it cannot be done should not interrupt man doing it' ~ Chinese proverb
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Ditto on the John Bridges forum. Those guys are great. Tell them your issues and they will give you good conservative advice. I used advice from that forum on a difficult install...............three years later.................lots of use and it is holding up great. One thing for sure................you don't want to have deflection causing your tile to pop. Not a good thing!!!! Tile size can be your friend................if you choose smaller rather than larger as has been said. JMO Mike L.
Is the hardwood already installed? If not, you might consider building up the subfloor under the hardwood to match the stone once installed.
Under the stone, I would use 1/2" ply, 1/4" CBU, and then install the tile. Top of tile above existing subfloor = 1-3/8".
Under the 3/4" hardwood, I would use 5/8" ply. Then you're flush.
Or just live with the 5/8" difference at the transitions.
The hardwood is not installed yet, the baseboard is, I only held it up one inch, figuring that it would give plenty of space for the hardwood to move, I didn't want to rely on just shoe providing the cover for expansion. Thats a minor and correctable issue though.
How about building the floor up whatever you need for the tile, and then making a beveled transition piece to the hardwood?
I've done that any number of times. Once its stained and finished, it blends right into the floor.
I usually make the bevel cut on my bandsaw, and clean it up with a belt sander or handplane. But it could be done several ways.
The information I passed along was from the Tile Council of North America handbook and should solve your height issue.If you want to build up more under the tile to be certian of no deflection issues, the simplest and cheapest option would be to make your own transition threshold between the tile and flooring. Speaking from personal experience, a 1/4" difference is not generally noticed by anyone but the installer and not a tripping hazzard as long as the edges are rounded or tapered.Building your own threshold allows for an exact height match from material to threshold, and would be hardly noticable with a great deal of money and effort saved.Once again, thin-setting ditra directly over your subfloor and installing your tile is perfectly acceptable according to the TCNA and Ditra's manufacturer.Ott
Thank you very much for your help. I'll definitely have to do more research now to ensure that I understand the procedure for installing ditra, but I think I am on the right track now.
If you go to a tile store that sells Ditra, it comes with an instruction booklet that gives you all the info you need. I could only buy it in something like a 3'x150' roll at my local tile store but I did come across it later at Home Depot in 50' rolls. The pricing was about the same but you didn't have to buy as much. http://www.shluter.com is the web site for DitraBe sure to use latex-modified thinset between the plywood and the Ditra. The sell Ditra-set, probably the exact same thing as any other latex-modified product but I used it anyway to avoid any possible problems.Also, the seams need taped in waterproofing applications.(They claim that Ditra can handle vehicular traffic)Hope this helps,Ott
The thing that might be of concern is the cost of the Ditra. I haven't used it but it looks to be at least 1/8" thick, so it appears you're only saving 1/8" of height buildup vs. using 1/4" CBU. I have used Kerdi, and it is not cheap.
Be sure to use latex-modified thinset between the plywood and the Ditra. The sell Ditra-set, probably the exact same thing as any other latex-modified product but I used it anyway to avoid any possible problems.
um, Ditra-set is un-modified, no?
k
Sorry about that, my brain was faster than my fingers. Latex-modified between wood and Ditra, un-modified between Ditra and tile. Ditra-set being un-modified.Ott
Edited 1/3/2009 10:01 pm ET by ottcarpentry
Sorry about that, my brain was faster than my fingers. Latex-modified between wood and Ditra, un-modified between Ditra and tile. Ditra-set being un-modified.
You got it. I wasn't really trying to call you out, but just wanted to clarify exactly what you just wrote for others who might be reading.
k
I haven't read through the entire thread....but so long as it won't effect your staircase(s), if any, I'd go and add the ply to the woodfloors to bring them up flush.
That's what I did with my own home. Little extra money and labor.....but gives you the finish you desire.
J. D. Reynolds
Home Improvements
With travertine, you want zero deflection.
The part that bothers me is the 19.2 inch joist span. It shouldn't take too long to pull up that subfloor, beef up your joist spacing (narrow it to, say 12 o/c), go back with 3/4" subfloor and proceed with ditra, or Hardi and tile away.
Jeffah,
Larger tile sizes require less deflection than smaller tile. Also, the type of material can handle stresses and deflection differently. Stone vs Ceramic, porcelain etc. the minimum I personally feel comfortable installing tile is 3/4 ply w/ 1/2 hardibacker/durock thinseted to it.
That being said, the 2008 TCA handbook for ceramic tile installation states that w/ a 19.2" o.c. Joist spacing, w/ thin-set and uncoupling membrane - 3"x3" and larger tile is allowed.
The layers allowed are as follows:
1. 19.2" o.c. truss joists
2. 23/32" T&G exterior-glue Ply w/ 1/8" gap between sheets
3. Latex-portland cement mortar bond coat
4. Uncoupling membrane (such as Ditra)
5. Dry-set or Latex-Portland cement mortar
6. Ceramic Tile
Providing that your flooring system is "in conformance w/ IRC for residential applications", It looks like you're clear for take off. Enjoy ;-)
Ott
there is a new ditra underlayment, ditra xl or something that is made to match elevations in hardwood and tile
I certainly agree w/ Mongo. Call Shluter and tell them exactly what your situation is. I was installing 16x16 marble over a questionable substrate and talked to them about my situation. The staff was helpful and knowledgeable, and they have to protect their warranty.We all come from our own personal experiences, and every situation has its own nuances. The manufacturer can say for sure. Remember that Shluter or another membrane may be expensive, but you don't have the cost involved in materials and time for installation of tile board. So, the additional remaining cost may negligible compared to the peace of mind. Ditra, for example, goes down quick and easily and can be tiled over immediately.As was mentioned earlier, Ditra-XL may be just what you're looking for. I don't have enough personal experience to recommend other types of uncoupling membranes other than I know they are out there.OttEdited 1/3/2009 8:50 am ET by ottcarpentry
Edited 1/3/2009 8:57 am ET by ottcarpentry
Hi Jeff
Good luck on your project. If it were my project I would choose Custom 5mil easy mat, peel and stick, for underlayment. Prolite mortar using 1/2 x1/2 notch trowel. The 5 mil peel and stick acts as a crack iso membrane which will absorb some flex if your floor has deflection. Custom's spec for this product allows for 3/4 sub-floor on 19.5 joist spacing. Prolite is a very aggressive mortar and the system together are more than adequate in my opinion. The problem with the Ditra system is that you must use unmodified mortar for the uncoupling system to work properly.I do not recommend using unmodified mortars on large format stone.
Craig
Edited 1/3/2009 4:08 am ET by CWHarimon
Good lord, people are giving you good advice, some are giving you horrible advice.
You don't want a height differential, but with the way the house was built, and with the product you are installing, you're going to have one.
Or you'll have a failed installation.
Some posters keep referring to guidelines for ceramic tile. Travertine is not ceramic.
Some posters keep referring to guidelines for standard-sized tile. Your design incorporates tile big enough to be considered large format.
You also have Advantech and not plywood as your subfloor. Different animals when it comes to setting tile.
Since ditra has been mentioned numerous times, go on the Ditra website, which is schluter.com (not shluter.com) and read the installation methods for NATURAL STONE over Ditra. I also recommend you call Schluter and tell them of your predicament. They'll give you a warm fuzzy, or they'll throw a cold bucket of water on you...but either way they'll give you good information.
In general, for ditra you're looking at 3/4" sub, and a minimum of 3/8" underlay over that, then ditra and your travertine. That can be modified a bit, but again, talk to the schluter kids to see how.
While I've used a lot of ditra, there are other membranes out there besides ditra.
You're also getting into the realm of large format tiles, and if your base is not dead flat, they can require a thicker bedding of thinset between it and the backer it is being set on.
If you haven't already bought the travertine, you can eliminate some of your problems by going with a porcelain or ceramic tile. There are some very nice faux-travertines out there that would allow you to do the versailles design that you're proposing while matching the height of the hardwood in the rest of the house. You'll get a pretty good faux-travertines look without the installation and maintenance concerns that come with real travertine.
"I have learned that the consensus is that the floor under the tile has to be 1.25 inches or more. "
First there are two different deflections that are important. The deflection of the joist. With the TJI you can the manufactor should have that in their tables.
The other is deflection of the subfloor/underlayment between joist. That is spec'd by standard systems that are given in the TCA booklet or proprietary systems spec'd by the manufacture.
ONE standard system is smooth plywood over a plywood sub-floor. In that case the underlay is staggered screwed into the sub-floor and missing the joist. Much like backerboard over plywood.
That system allows for direct installation of the tile on the underlayment. So other NO OTHER backerboard is needed.
I don't have the TCA handy, but IIRC the sub-floor and underlayment are each a min of 5/8", thus a total thickness of 1 1/4"
But this is ONLY for one 16 OC joist.
And it ONLY COVERS that one system. there are number of other systems, such as backerboard over plywood that is a different buildup.
And different systems for 19.4 and 24" OC.
Ott and Mongo gave you the right direction.
The best that I remember none of the TCA systems allow for thinset (either for tile or backerboard) directly to OSB.
And I would wonder about the wax in the advantech might inhibit bonding.
And Ditra is a proprietary product so I would pass this by them.
William the Geezer, the sequel to Billy the Kid - Shoe
The TCA booklet is on $10.But they have not gotten into the modern age. You need to print out the order form and mail it in with a check.http://www.tileusa.com/publication_main.htmAnd they have a Q&A including this."No, the TCA Handbook contains installation guidelines for ceramic tile. The Marble Institute of America publishes the guidelines for installing natural stone. They can be reached by calling 440-250-9222."http://www.tileusa.com/faq_main.htmhttp://www.marble-institute.com/.
William the Geezer, the sequel to Billy the Kid - Shoe
Thank you very much for all the replies. There is definitely a lot of information out there. I have already sent an email to ilevel for specific deflection specs for my specific application. However I did find on their website a table which gave allowable spans that could attain a deflection rating of L/480. With my layout and depth of joist a span of 18' 1" is allowable. So with my span of 11 feet hopefully L/720 is attainable. That would just leave the OSB deflection in question.So advantech's website has a table that reveals that a span rating that allows a rating of L/360 with my application that is 212PSFI just reread the chart, i was reading it wrong. how does a PSF rating relate back to tile installation. The joists were rated at 40 PSF.any input on that? Good call on the dishwasher fit too, thanks for that.
Edited 1/3/2009 11:50 am ET by jeffah
Whatever tile/underlayment system you use, make sure that you'll leave enough room to install a dishwasher.
They'll all likely jump on me for saying this, but what was advised when we did our bathroom was to staple down expanded metal mesh, wiring the edges together at joints, and then cover with thinset to the depth of the mesh.
A mud job! That's what I'm talking about (see my above post). Thats what they did way back when. A b!+@# to get up!
First, to the OP - spend some time on the John Bridge forum. Incredibly knowledgeable people there (pro Tilers by the bushel load) who will point you in the right direction. I learned a ton reading posts there and got great guidance on my first ever tile install - Vermont slate for my reproduction colonial Saltbox's mudroom. It was about 200 sqft including a bath and it came out pretty good. Not great, but that's me being particular... I got many great compliments on it.Also, with large format natural stone.. heck, with just about any tile floor... I think that an isolation or decoupling layer like Ditra is just smart protection against tile/grout cracking. Interstingly, it's based on centuries old tile practice of setting tiles on beds of sand... tile installs that are natural stone, hundreds of years old... and no cracks.Sure, it adds to cost, but the install time is so much quicker than Hardi or other cementious products plus you can tile on it right away
you probably make it back in saved labor... and if its for your house... well, you probably have a whole s-load of other stuff to do, right? An added bonus with Ditra is that it's waterproof... many other tile substrates are NOT. So, great for bathroom or mudroom floors.One poster had an issue with unmodified thinset... (which is required for Ditra between Ditra and tile so that the thinset can properly cure... b/c Ditra is waterproof the modified thinset takes weeks to cure vs unmod. which cures in it's normal time.)... what is your issue with unmod?Looking at Ditra install specs, seems like you're going to need a 2 layer subfloor for use with their product + natural stone.http://www.schluter.com/media/brochures/DitraHandbook-2008-ENG.pdfsee page 8
Hi. I was the one who brought up that you need an ummod mortar with detra. I have nothing against unmod mortar. As a matter of fact I buy it by the pallit. I just think there are better products than detra. One of its claims to fame is that it can withstand cars, so will a set without it. I have a 3 year old set, 5200 sq ft auto showroom 13x13 porcelain with 20x 20 boarders, that was set with unmod on ground concrete with Ardex p 51 primer. I made them wait 28 days before traffic but no breaks after 3 years service. Now for the project being discussed, I agree that an iso membrane is what he needs. I just don't think detra is the best choice out there any more.I still use the Ditra when an architect specs it. It is my opinion that a better set (better by being 1 faster, 2 cheaper, 3 Simpler) can be had by using other systems and high performance mortars ( Tec 3 in 1, Mapi Ultralight, Custom Prolite). Thanks Craig
Thanks for the reply Craig. That makes sense.
You are welcome Sir.
first can you add joist from below to stiffen up the floor so there is no bounce to it. if you can then you whould be able to glue 3/8 backerboard,thin set ditra, tile and you should be ok. the floor should not have any deflection in it or the tile will come up over a short time good luck jimbotg
I have looked into installing additional joists underneath. There are no plumbing pipes in that area and when the electrician went for his close in inspection he had not pulled any wires across the basement since it is unfinished. making the spacing 10'OC however is going to make recess light install difficult later. Since it seems that most of the deflection i have to worry about is in the plywood, could i just install 2x12 blocks perpendicular to the joists every 4 feet, tying the joists together and reducing plywood flex.Thanks