no method in tcna 2013 book

[Proven One]

Can't find a accepted method tiling over wood no matter what without having t&g ply wood subfloor. I understand you can remove the subfloor and put down t&g ply but that just adds more cost to a remodel. Is the tcna book geared towards new construction I don't understand how they don't have one approved method listed....I know it can be done having done many many remodels that don't have t&g plywood but does that mean its wrong. If someone wants to play by the rules I don't think you should pick and choose what ones. Let me know if I'm missing something here it seems odd to me

[cx]

Eric, I think you're gonna need to be more clear on your question.

Are you intending to bond your tiles directly to your plywood?

While the TCNA Handbook lists only plywood in its published methods, the ANSI standards list other suitable subflooring materials, such as better quality OSB and sawn boards.

Many tile installation substrate manufacturers also list OSB as a suitable backing material.

The first layer of subflooring is required to be T&G or to have blocking installed under the between joist joints, but the second layer, when required, is not required to be T&G. You will find that in the TCNA methods that indicate a second layer of subflooring, including the method for tiling directly to the second layer of plywood used as an underlayment.

And the Handbook doesn't publish every possible combination that could be used effectively for installing ceramic tile on a floor.

Give us more hints about what you wanna do that you think isn't recognized.

[Proven One]

Sorry I wasn't clear. This is not for a project but more of an observation.

Every method listed in the tcna handbook shows the use of a t&g plywood subfloor.

There are no methods listed for anything other than t&g plywood

So I've done jobs where the subfloor is non t&g 5/8ths and build up from there....but no matter what you do on top of a non t&g subfloor it is not acceptable according to the tcna handbook

I don't own a copy of any ANSI material but I'm begining to think I should. I was under the impression that if it wasn't in the tcna handbook your screwed.

It just seemed strange to me that the tcna handbook which I've believe has been referred to as the tile bible didn't have a listed method for building a suitable tile base over subfloor that was not t&g plywood but have a method that includes the use of mastic.

[cx]

The T&G is a requirement regardless who's specifications you wanna look at. If you don't have T&G, as I said above, you must provide blocking under all those joints. Nobody in the industry is gonna give you a pass on that.

Tiling over a single layer of nominal 5/8ths" plywood subflooring over 16" joist spacing is a very poor idea as far as I'm concerned. Tiling over nominal 5/8ths" plywood that is not T&G or blocked is just suicidal in my book.

[jwmezzanotte]

CX

You mean tiling to the subfloor itself, or just going over one 5/8" layer in general?

Ive done it with strata mat and ditra, both say its ok. Obviously id prefer another layer when I have a choice.

[Proven One]

I would never consider tiling directly on the subfloor ever.

My point is that if you have a regular 5/8ths plywood subfloor properly prepared with blocking. Add additional plywood underlayment let's say 5/8ths. That brings us to 1 1/4 let's throw any tile approved substrate you want then tile it. Its not an acceptable method as per tcna handbook.

I would just think that if there is a proven method for something I believe to be a common residential situation that it should be in the tcna handbook. If my above hypothetical situation included the subfloor being t&g there would be no issues.

It just made me feel like any of the jobs I've done over non t&g subfloors should be frowned upon. Once again I'm not saying tile on the subfloor just that the subfloor is not t&g plywood.

I feel like I should have had a better way to ask this, sorry I'm not trying to mislead or confuse anyone.

[eurob]

So Eric, are you talking about methods for new constructions or renovations ?

[cx]

Originally Posted by Eric

My point is that if you have a regular 5/8ths plywood subfloor properly prepared with blocking. Add additional plywood underlayment let's say 5/8ths. That brings us to 1 1/4 let's throw any tile approved substrate you want then tile it. Its not an acceptable method as per tcna handbook.

We must have different TCNA Handbooks, Eric.

That method would meet or exceed the requirements of every manufacturer of tiling substrates I'm aware of and all the Interior Floors Over Wood methods in my 2013 Handbook, including the one for tiling directly to the second layer of plywood.

Some sorta misunderstanding here, but I'm not sure just what it is.

[madronatile]

We see a lot of 3/4" dimensional sub floors here. Custom allows Wonderboard directly on this. Seems sketchy to me.

[PetrH]

Sounds like what Eric is getting at is that builders in his area use (or used) regular plywood instead of t&g. What CX is saying is that if you add blocking under all unsupported joints, you now have a T&G equivalent as far as standards go.

[Tiger pilot]

Believe I'll jump in on this one since I sit on the TCNA Handbook committee. Our goal in providing methods in the handbook is to provide a method that EVERY MANFACTURER agrees with in EVERY application. Now that means we know those always work everywhere. We also know some installers, or some locations, do other methods that work. We just hear from other professional installers working in other areas telling us it doesn't work in their area.
There are no tile police out there, just jobs that fail if you choose to ignore the handbook.

[John Bridge]

Before I became a tile setter, lo these many years ago, I was a framing contractor. That was in the very early seventies, so I know personally that at that time and some time before, t&g plywood was the norm for wood floor construction in both residential and commercial construction. And I imagine that code/standard was adopted in most/maybe all jurisdictions in the country.

If someone uses non-t&g plywood as a first layer subfloor they are defying standards that have been in place for four or five decades.

What is it we are actually discussing here?

[Proven One]

Hey guys.

Yes most homes I've worked in are not new mostly built from the 60s and up

These homes generally have 5/8th plywood subfloors or t&g shiplap

I know the handbook covers a lot and that's good. I suppose I was assuming more homes are built like the ones here and the handbook was just geared towards new construction.

Though from what I've been hearing a lot of new construction here is tji joists and 7/8ths t&g OSB subflooring.....I know you can get t&g plywood from just about every lumber yard. Guess price has something to do with it

I'm going to look into picking up ANSI material thanks for the replies

[MDtile]

New construction in Cali you will find 99% of the time OSB T in G between 3/4" and 1 1/8", usually on engineered truss joists OC never more than 16" and sometimes 12". Some Strata Mat and I'm good to go regardless of what the TCNA says. The builder isn't on board with any additional underlayment, unless a wood floor is at the break, and then I switch to Hardiebacker to gain height.

Just saying what is the norm around here. I almost never see plywood sub floors anymore.

[MAPEI - Technical Service]

In my job I get daily requests to warrant systems that aren't done by the Handbook or industry best practices. Most of the time, these are driven by two criteria: 1) it's cheaper or 2) they don't have product X on the shelf but product Y is available and isn't that close enough? It can be difficult to find tongue and groove plywood at a big box store. Builders like to use OSB because it's less expensive. Neither of those situations is going to cause me to write a warranty outside of our data sheets for our products because I know from testing the systems that they are more prone to failing. Not that they WILL fail necessarily, but that they have a higher likelihood for problems.

There are lots of variables that go into putting down a tile floor. As Steve pointed out, the Handbook committee tries to find a consensus method that is going to work in a vast majority of cases. That means that the methods are going to be conservative. Manufacturers make products for specific applications that may deviate from the Handbook so their technical data sheets will trump what the Handbook says. If neither the Handbook nor the installation products manufacturer say that you can do something in a particular way, you may want to ask yourself if you should be doing it that way.