trying to match 3/4" hardwood height [Archive] - Ceramic Tile Advice Forums - John Bridge Ceramic Tile


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08-05-2019, 11:50 AM
new build for son- we are doing tile due to lack of money-3/4" bellawood will meet 1/4" porcelain tile over 1/4" hardi board . I need to know if this will end up at 3/4" or higher and what size of trowel for bond between hardi board subfloor and hardi board /tile to come up at 3/4 " I also wonder if I butter will it raise tile too much above 3/4" and which profile thickness should I use from home depot 3/8" or 5/16" since 1/4" is not offered. I hope to nt cause the hardwood to be shimmed thus asking here. Motown plumber ( I know I can do a sample -just thought a pro may know already best way frward

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08-05-2019, 01:41 PM
First a couple of questions:
- are you certain that the structure and subfloor are properly prepared for tile?
- most tile are thicker than 1/4", are you sure of that?

HD has access to all of the Schluter profiles by special order, and if in a rush, you can order direct from them, so you should be able to get the exact one you want. you can search them on this website:

The thickness of thinset depends a lot on how literally flat the surfaces are. Many tile are not perfectly flat on the bottom (cupped, warped, twisted, etc., albeit maybe only slightly)...the further from flat any surface is, the thicker you need to make the thinset. Also, if any one dimension on the tile exceeds 15", you should be using a LFT mortar, and generally, that needs to be installed a bit thicker. It's always a good idea to burn in a layer of thinset on the back of the tile...this could end up being literally paper thin if it's flat, or deeper to make the tile's back now flat, if it's not. The flatness of the subfloor would then determine how thick your notches would need to be.

Industry standards call for a certain degree of flatness, and if not currently there, calls for fixing that prior to installing the tile. So, those standards are based on the longest side of a tile...the bigger the tile, the flatter the floor must be.

So, not giving you a specific answer without some more information. My guess is that the tile would end up above the hardwood using 1/4" backer. An alternative to that might be Ditra or DitraXL, which saves the step of the backer and all of the screws and taping of the seams.

08-05-2019, 02:26 PM
Thanks, as far as the subfloor being prepared for tile question, I have only started educting mself and absent I believe wonderboard install instructions mentioning leave 1/8" gap o subfloor ( no reason given) I do not know of any spec for subfloor other than 3/4 cdx being ok due to being over 5/8" minimum.
Thanks for recommending measuring tile. I will buy hardiboard thinset and tile and piec of hardwood to set up a test on actual thickness. If you are correct, would I shim the hardwood 1/8 say to bring it up to tile and if so is there thinset needed in the airpocket the shim cause or some writte approved procedure absent removing 3/4" sub floor and install 5/8". I will look at the stuff you mentioned yet wonder its total height with 1/4 or 3/8 tile.I project 30 or 40 feet of transition ( linear) so I want to find a way to do it right (match hardwood height without routering .What size trowel would I want if i do test with buttering paper thin tile back to keep height down?

08-05-2019, 03:15 PM
Love the membrane by schluter ditra. I will go with this where can i go buy this and maybe even tile to end up at 3/4" and use their profiles I am in Detroit?

08-05-2019, 03:59 PM
A CDX is NOT sufficient. Your underlayment must not contain a D-face, and MUST be T&G, or you have blocking installed across all joints (much easier to deal with a T&G panel designed for subflooring. A 5/8" panel would be the absolute minimum to meet industry specs.

Then, it is important to know the span of the supporting joists, their species, spacing, and height. For a solid ceramic install, it must be at least L/360. Use the 'Deflecto' tool in the blue bar above. Note, the span is NOT the room size, it is the unsupported length of the joists, which usually is larger than the room.

08-05-2019, 07:06 PM
Mot toung groove. Not pulling it up. Can I do something to the square cut cdx 3/4 to still install tile without pulling up? would the membrane work on it? I can change the floor orig designed cdx to accept nails for all hardwood, tile was last min change

08-05-2019, 08:00 PM
Mot toung groove. Not pulling it up. Can I do something to the square cut cdx 3/4 to still install tile without pulling up? would the membrane work on it? I can change the floor orig designed cdx to accept nails for all hardwood, tile was last min change

You may have success by adding 3/8" or 1/2" plywood over what you have with an acceptable face grade, but then you're abandoning your hope of getting the floors even with each other.

To add blocking, you'd have to have access from underneath, and have someone hold the blocking in place spanning the plywood joints while a second person drives screws in from above. You can use 2x4's for the blocking, or 4" rips of plywood, cut to about 1/2" shy of the width of each joist bay. 2" deck screws would be sufficient.

If you don't have access to the floor from underneath, then you would have to take up the plywood to add the blocking. If you don't won't to do that, I would recommend you not install tile over the floor, as it would definitely crack along the plywood seams.

08-05-2019, 08:29 PM
Like others have said you need to determine how strong your floor is in the deflecto calculator using beam length and thickness and height. I think you need to think of do I want to install tile okay I will install tile correctly and height at the wood floor be damned. I was like you before trying to match the floor but don't worry about that a little step isn't a problem at all. I'm just about to wrap up a basement bathroom and it's going to be at 15/16 in 1 doorway and 1 1/16 difference up to the tile in another doorway. I will make a 2in ramp out of wood that goes on top of the vinyl wood look floor and is level with the tile

08-05-2019, 10:01 PM
The problem with D-faced stuff is the voids. Tile doesn't like voids, and it is less strong. If it's sheathing grade ply, the internal plies may also have voids. Underlayment grade stuff does not...any knots will have plugs so all layers will be 100% intact with no voids.

08-06-2019, 05:46 AM
As far as the differing heights of the flooring, where the Bellwood meets the tile, won't you be using a threshold at that joint? If so, the 1/4" or so difference in floor height will not be noticed.

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08-06-2019, 06:22 AM
I just double checked my plumber assumption with the builder. He DID use tongue and groove cdx subfloor over #2 pine 2x10 joists 16" on center. He did say that 1/4" tile I plan on using on either hardi board or dietra xm would crack and it had to be tile rated for floor, so I have to ask here will this work for me to achieve my close to 3/4" height? He did say he would install the hardwood first, so as to not force beginner son to layout entire mixed material 800 sq ft floor. Here is what I thougt I was gonna use.

will this work and not crack ? It says floor rated, it is on sale and porcelain and it is 1/4" - I can afford this. Which system hardi or diera considering the 4 ft of linear profile I need to join hardwood solid bellawood.

08-06-2019, 07:23 AM
Welcome, Michael. I'll capitalize your signature name since it appears you've lost your shift key. :)

What is the unsupported span of those 2x10 joists?

While it is helpful that your CD plywood has T&G edges, the grade is still not adequate for a ceramic tile installation for the reasons cited above. The use of a CBU as your tiling substrate will help somewhat to alleviate some of those deficiencies, but it's still not a suitable subflooring material.

Not sure just what you're referring to as a "profile" between your tile and hardwood flooring, but you don't actually require anything there other than a movement accommodation joint, which can be nothing more than a gap filled with a flexible sealant. If you have differing heights of flooring, I'd generally make a wood reducer to match or closely approximate the wood flooring that would match the height of each flooring material. Generally very easy to do.

My opinion; worth price charged.

08-06-2019, 08:13 AM
Thank you. The house is 26 ft deep and a beam is 13 ft down center so I plugged in deflocto meet even at 14 ft and exeed 360. correct if wrong.
I double checked again with builder. IT is CDX tongue groove stagered over 2x 10 pine joists 16" on center.
Pleas expand on comment not suitable for tile if cdx. And is here a remedy"
4 areas of tile.
1. 8x11 kit
2. 6x4 square at front door
3. small bath
4. small utility

I like the profile look of brass 1/8" strip between wood and tile just saying .
abandon tile idea?Motown

08-06-2019, 08:43 AM
Pleas expand on comment not suitable for tile if cdx.See Post #9. And is here a remedy"
See Posts #7 and 12.

If you wanna tile over what you've got, that's up to you. We can only tell you what the ceramic tile industry recommends and where the smart money is betting.

If you like the look of a brass strip between your floor coverings, by all means put one there. But you still must provide a movement accommodation joint at that junction.

My opinion; worth price charged.

08-06-2019, 09:00 AM
Thanks, builder got pissed when I asked for spec on subfloor cdx said crawl under take pic. Rep from schulter dmx just called. He said I should use detra xl which is 5/16" thick, 3/8" tile to match height of 3/4" hardwood.And a profile that is a 1/16" to 3/32" higher than tile thickness when physically held on different profiles -said prob 7/16". He did not know about putting his detra over cdx. But said I should be fine since its regular plywood commonly used.

08-06-2019, 09:05 AM
Just quit worrying about the difference in heights or go hardwood everywhere. Do it right and make or buy transitions. After you put on a new half inch of plywood and you ditra or CBU you can then determine what height transition you may need to buy or order if you want metal. I didn't Google you're Hardwood brand but if it's ever going to be refinished I like to make these transitions removable. I usually use Oak and Mill a piece of wood that has about a 3/16 lip on both surfaces and a ramp between them it's usually about 2 in wide. For hardwood floors that may need to be refinished i countersink three or four screws across the door width and then plug them with a dowel plug. This way the Dowel plugs can be drilled out and the transition removed for the hardwood floor refinishing and then put back in position and I have done this and it looks perfect after reinstallation and a new finish

08-06-2019, 09:40 AM
Michael, I'd recommend you measure your proposed hardwood flooring to see what thickness you'll actually be dealing with. I doubt it will be 3/4" thick.

My opinion; worth price charged.

08-06-2019, 09:56 AM
So sounds like 3 options.

1. tile over existing cdx and not piss off builder anymore ( we are both 70 by way)...... and stick to smaller tiles maybe 12 x 12 or 6x6" with it if it cracks due to air pockets in cdx...
2. add 1/2" plywood which piss off builder cut all doors
3 go to original hardwood in kitchen and entrance square...tile the bath and laundry where a crack wont be seen.

Leaning towards 1.
If I go 3.....should i apply redguard or waterproof subfloor cdx under hardwood?
Thanks all....and is the ditra worth cost ? close to ordering in Motown

08-06-2019, 01:55 PM
If you read the installation instructions for ANY tile underlayment material...they all call for a proper subfloor. You do not have a proper subfloor, so any testing that they may have done is invalid.

FWIW, the size of the tile has nothing to do with whether it will have cracks or not...larger tile requires a flatter floor, but other than that, if it's going to crack, doesn't matter what size the tile is.

If you added a nominal 1/2" ply on top of what you have, then a tile underlayment (Ditra is one of your thinner choices), then it should be okay. Otherwise, who knows...odds are, things will crack. That might happen right away, or it might take 5 or even 10-years. Throw a party and have 20-people dancing, and it might crack immediately.

08-06-2019, 04:02 PM
Where is this tile going and how is it just much cheaper than hardwood? Between cement board, thinset, trowels, buckets etc is there really that much of a difference to just more wood when you are already putting wood in?

08-06-2019, 04:20 PM
new build for son- we are doing tile due to lack of money-3/4" bellawood will meet 1/4" porcelain tile over 1/4" hardi board .Charlie, I think he means they are doing the work themselves to save money, not that the tile is the less expensive option.

08-06-2019, 05:08 PM
I think laundry and bathroom should be tile no Hardwood kitchen can be hardwood but I still think tile is better there. I have hardwood in the kitchen and a plate dropped straight down bounced up and I caught it and it didn't break. But tile is better and in vogue. Cutting three doors takes 2 hours they shouldn't even be on yet. Here is an oak threshold I made to match a 3/4"hardwood floor . The tile is on half-inch plywood and then ditra similar to what you may have. It looks about 1/2" step down. This has never been an issue to walk across. . Also here is my design I'm considering for my 1 inch ( yes
1" difference) step up from Vinyl waterproof snap-together flooring to my current tile project on ditra heat duo on 1/4"-1/2" SLC. I'm considering leaving a 3/16 Gap put some backer rod in there and then caulking with sanded grout rather than make the threshold 3/16 inch taller and overlap onto the tile my tile edge is straight. I will have about 3/4 inch a flat contact surface for my threshold against the floor and will use Liquid nail probably

08-08-2019, 06:17 AM
Thank you one and all for educating me on subfloor. I decided to just tile the bath and utility room and omit the kitchen and entrance by making them also White Oak Bellawood 3/4"- saving all the cut ins and some money and reducing concern of cracking in visible area.
I can do Hardibacker or the Ditra and my question is the tub joint and the perimeter . I saw Ditra "tape" tub and wonder what the pros do at the tub besides silicone caulk and what if anything should be done for expansion considering 7x7 and 7 x9 small rooms and 1/4" porcelain on either Hardi or Ditra. Motown

08-08-2019, 06:37 AM
I have a question related. If its consensus that 1-1/8" minimum or equivelant and no cdx 3/4" single layer is spec'd here by many,why does Ditra installation hand book state on page 4 the following. ....
......16" o.c. joist spacing, single layer OSB or plywood subfloor-
Areas of application-over a even and structually sound o.s.b or plywood subfloor with 16" o.c. joist spacing
( page 4

Why miss the chance to explain "structually sound plywood" such as NO singl layer CDX which is all new builds where I come from- ?

Sales would drop?

And if their lawyers put that structually sound qualifier in there for future lawsuits - Paragraph is single layer wood.....says single layer plywood subfloor- and cdx not 50 $ a sheet sanded high grade is used for subfloors this decietful not mentioning cdx only structuall sound? I argue no such thing as structually sound single layer plywood---- used commonly and merits mention the fact. or you argued .....may go to wonderboard due to this flim flam from Germans. Motown

08-08-2019, 09:17 AM
Michael, best advice I can give you on the CD plywood as a subfloor for your tile installation is if you like it, you use it. The industry, and Schluter Systems, recognize that CD plywood does not qualify as "structurally sound" material for your application. The presence of large open voids on the surfaces and in the inner plies is what renders it unsuitable. The generally poor quality of the materials used in CD panels contributes, but is not necessarily addressed. I think if you'll read all of Schluter's instructions you'll find somewhere that they address "plugged" faces, which you will not find in your CD grade plywood.

If you are using a CBU over that kind of subfloor, rather than any sort of bonded membrane, your chances of success in a ceramic tile installation are improved, but I'd still avoid it in all residential subflooring applications.

All joints between your ceramic tile and dissimilar materials require a movement accommodation joint of some sort. It can be an open joint if it will be covered with something like baseboard, or it can be filled with a flexible sealant, but it must be there.

There is no "consensus" that a minimum of 1 1/8th" is required anywhere in the ceramic tile industry. I'm guessing you mean subfloor thickness there and that is a common misconception. The subfloor requirements are specified in the ANSI standards or in manufacturers' instructions, but you'll not find any mention of a minimum total thickness 1 1/8" or 1 1/4" as sometimes mistakenly mentioned. The minimum subflooring in the tile industry is actually nominal 5/8ths" plywood over 16" joist spacing, but I wouldn't install ceramic tile over that on a bet.

My opinion; worth price charged.

08-08-2019, 03:18 PM
CDx plywood is typically labeled as sheathing, which is different than subflooring. WHat you want on a floor is something designed as subflooring. Sheathing is generally fine on an exterior wall because you're not walking on it, so the voids aren't a big deal.

Plus, subflooring must have either a T&G joint to keep the long edges aligned or have blocking installed along each long edge which sort of negates the savings of using square edged materials.

Those in the industry at least SHOULD know the difference. Now, whether they abide by it is another thing altogether. There's a big incentive to save a buck. In other places, longevity is a much larger, with our disposable society, short term, looks good for awhile until I tire of it is more the norm than something built to last eons.