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We are talking about structure. deflection rates aint just for tile!
Engineers are great at filling blackboards and sheets of paper with squiggly lines, and on many occasions theory does cross disciplines. But in my experience, those same engineers often suck at practical solutions to real-world situations.

TCNA specs are based not only upon theory, but empirical evidence as well. Play nerd all you want, but bottom line, building to "industry standards" and/or warranty requirements does not allow you to change the recipe according to what you think is acceptable.
 
A floor built to a L/360 Deflection rating is required in any home that is built here in Vancouver. Few are built better than this.

In Vancouver most framing I see is 16" on center floor joists with 5/8" sheathing. That's it. Some glue, some diagonal blocking (maybe), a few nails from the framing gun - tap, tap, tap. And you have the "Vancouver Special" subfloor. This floor meets the requirements from the TCNA for deflection and the local building code. Is it good for tile? No, not if you want to follow a TCNA specification guideline.

Now you can add some more plywood. An extra sheet of 5/8" plywood and your good to go.

You can add some Wedi - good to go.

You can add some Ditra - good to go.

You can add some Hardi Backer - good to go.

You can add some cement board - good to go.

The original post talked about a Proper Subfloor. All of the above are proper subfloors for tile. All of the above are listed in the TCNA guidelines plus many more options. Regardless of what you add on top your adding an underlayment of some kind to get the Sub Floor Tile ready and making it proper.

Now if you don't entertain, weigh 120 pounds and don't mind minimum code you can build it to a "residential service rating" or you can built it better. Just ensure you install each floor as per the manufacture's guidelines and TCNA specs.

There is a huge number of ways to build a proper subfloor for tile. Choose the one that works best for you. Just don't tile over the basic "Vancouver Special".

JW
 
Engineers are great at filling blackboards and sheets of paper with squiggly lines, and on many occasions theory does cross disciplines. But in my experience, those same engineers often suck at practical solutions to real-world situations.

TCNA specs are based not only upon theory, but empirical evidence as well. Play nerd all you want, but bottom line, building to "industry standards" and/or warranty requirements does not allow you to change the recipe according to what you think is acceptable.
Like I have said before I build way above what the stupid TCNA book says. I have never once read a book on tiling yet no failed installs in 15+ years. Just because TCNA may say adding wedi does not make floor stiffer and deflect less does that mean it don't! Is my experience not correct and have I been "lucky" on my last 200+ installs? I will always build what I think is acceptable if it's minimum or not but trying to tell someone there method is wrong because a book don't say it's right is crazy talk. But like my stance has been on this whole thing yes wedi will increase a floors stiffness more so than ditra.
 
Like I have said before I build way above what the stupid TCNA book says. ...
As do I in most renovations but the TCNA is not stupid. It's your best guide for multiple install scenerio's. Wedi is a member of the TCNA. So is Schluter. Noble. Hardi Board. Custom.

These products tested and specified in line drawings grouped by common areas of tiling, ie floors, walls, showers etc.

The original post was on a proper sublfoor. The Specification Guide has dozens and dozens of ways to do this. You will find online people asking this question time and time again and a common response people inquiring about cement board is it does nothing to increase the deflection of a subfloor. These people might be talking about the span over the floor joists but not the span between the floor joists. And with 16" centers cement board can be used to make a proper subfloor like we have mentioned above.

The testing procedures for residential, light commercial and heavy duty are not posted online to my knowledge and you would most likely not find them unless you joined the TCNA as a manufacturer. Try emailing Eric from Noble Company. He might know the procedure.

Eric Edelmayer <eric@noblecompany.com>

JW
 
WOW--After reading all that I need a nap.
The service ratings are based on ASTM C627
(the robinson test) It is based on both loads and wear.You load it with up to 300# on different wheels ,soft rubber,hard rubber,steel, that go around and around..Cracked Tile or Grout is recorded until failure based on a % ...
 
JohnFRWhipple said:
I thought you where looking it up. Where's Eric when we need him.

I shoot him a link to this thread - lets see what the top tech at Noble has to say about service ratings.

JW
Lol I thought you were going to look it up...

I did look through tcna but could not find info

Is it a tcna rating? Or ansi? Or that other I think iso?
 
ee3 said:
WOW--After reading all that I need a nap.
The service ratings are based on ASTM C627
(the robinson test) It is based on both loads and wear.You load it with up to 300# on different wheels ,soft rubber,hard rubber,steel, that go around and around..Cracked Tile or Grout is recorded until failure based on a % ...
So does light com. mean it made it to the steal wheels?
 
WOW--After reading all that I need a nap.
The service ratings are based on ASTM C627
(the robinson test) It is based on both loads and wear.You load it with up to 300# on different wheels ,soft rubber,hard rubber,steel, that go around and around..Cracked Tile or Grout is recorded until failure based on a % ...
Thanks Eric. Then someone weighing 320 can't use their new bathroom?

JW
 
Thanks Eric. Then someone weighing 320 can't use their new bathroom?

JW
If they walk around with high heels on then prob not. I wonder what surface area of the wheel is in contact with the floor when being tested. There's a massive difference between a load being spread out across a 5sq in area compared to a 1sqin area.
 
If they walk around with high heels on then prob not. I wonder what surface area of the wheel is in contact with the floor when being tested. There's a massive difference between a load being spread out across a 5sq in area compared to a 1sqin area.
I spend a couple weeks in Disney Land just recently and as a general snap shot of America both Canadians and Americans alike I would think a large amount of our population is 250 plus, and I'm sure they walk like me heel to toe, one foot after the other.

What is even sadder than this is how many kids are so huge. Like massive huge.

Is the framing requirements for our floors taking this into account? Is your subfloor OK to handle your fat ###? :no: :blink: A touchy subject but man if your building your home and ever plan on entertaining you better check that your floors can take the weight!

JW
 
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