installing Travertine floor tiles

DENNIS R · 06-11-2011, 07:16 AM

I am the home owner and a project is being done in the bathroom. After it was installed, last week, 3 tiles have cracked, 2 very noticeably and one 4 inches on the corner, much smaller.

Should I be concerned ? Could those just be replaced and not worry ?

What is the correct thinset, amount of correct thinset thickness, starting from the wood underflooring, he laid cement boards as well.
What are the correct procedures and questions I need to ask.

I want to remove a section and determine if everything is right before he moves on .

Desperate home owner..

**oh'mike** · 06-11-2011, 07:58 AM

Fist thing to check is the framing---How big are the joists and how long.

Next the subfloor--what is it and how thick?

Cement board needs to be set in thinset,just like a tile.

Next is the size if the tile---trowel size depends on the size of the tile

Next is the thinset---thinset is a powdered cement material --no premixed stuff in a bucket will work.

Post a picture--and add some details---Travertine is soft and needs to be supported well.

No guesses from me until I get a little more detail,---Mike---

DENNIS R · 06-11-2011, 08:43 AM

Thanks Mike.

Here is more info

Tiles are filled and honed- 18 by 18 inches

Subfloor- 3/4 inch wood, another 1/2 wood, cement board, not sure how thick.

half of room is an addition and half original with the extra 1/2 wood.

Heated floor system as well.

Thinset was not a pre mix- Mapei-Keraset- TILE Mortar- it says on the bag max size of tile 16 x16.

Thanks

**oh'mike** · 06-11-2011, 08:53 AM

Any idea about the size of the floor joists? This does not sound good---part of the floor is in the old part of the house--part in the new section.?

The cracks--are they in a line?

DENNIS R · 06-11-2011, 10:33 AM

Mike,

I don't know about the joist..

The cracks are not in a line, they are in the old section.

I know the old wood base was not great..it had give..this is why they added the extra 1/2 inch...

Thanks,
Dennis

Daniel Holzman · 06-11-2011, 12:38 PM

Mike's point about the floor joist spacing and length relates to the stiffness of the floor supports (the joists). 18 inch travertine tile requires a very stiff floor to avoid cracking. You cannot stiffen a floor adequately simply by installing another layer of plywood subfloor, or cement board. The only way to determine the stiffness of your existing floor is to measure the actual dimensions of the joists, and measure the clear span, and determine the species of wood (an experienced person can usually guess adequately by looking at the joists).

The stiffness of a floor is typically measured by the L/D ratio, which is the ratio of maximum deflection at the center of the joist to the length of the joist. For example, if the maximum deflection is 1 inch, and the joist is 12 feet long (144 inches), the L/D ratio is 144. Determination of the deflection requires knowledge of the dead load, live load, span, and joist properties. There are on line calculators for this ratio. For travertine, the minimum recommended L/D is about 360, although some authorities recommend as high as 720.

The penalty for a floor which is not stiff enough is cracked tiles. There are other possible causes for cracked tiles, so the cure depends on an accurate determination of the cause. This needs to start with determination of the stiffness of the floor, which of course should have been done by the tile company before they did the job.

Bud Cline · 06-11-2011, 01:03 PM

Jheeeeezh Dennis !!!!!

I spend all of that time on your other thread answering all of your questions then I find this thread. Why do you guys do this? Why not stay with a single thread on a single subject?
Proper thinset and thickness

DENNIS R · 06-13-2011, 11:33 AM

I have some updated answers to the questions everyone has replied with. Thank you to everyone helping with this as my contractor is on site and before we finish the bathroom I need to make a smart decision.

span is 16 ft
2 x 10 joist 16 from center, doubled every other joist.
not sure if spruce or pine as of yet.

Reminder that the new addition part is 10 ft by the 16 ft
the original part is 8 ft by 10 ft.
The old sub floor was from 1985 it was approx 3/4, told probably not screwed, and the extra 1/2 was added probably nailed also. We then added 1/4 cement board, Heated floor system and travertine tile.

The cracking on the tiles is in the old section of the remodel.

JazMan · 06-13-2011, 10:55 PM

Hi Dennis & all,

As mentioned, please keep all Q's concerning this project in one thread. As it is now we don't know where to answer, or to just say chuck it.

I'm coming in late so I'll just start anyplace:

I can't believe your 2x10" joists are spanned 16', are you positive? You also need to determine the species and grade.

Quote:

I want to remove a section and determine if everything is right before he moves on .

Obviously not right.

Someplace you mentioned that Keraset (not so good) was used to install the porcelain tiles. If so, that is not the right mortar unless it was mixed with an additive.

Bud and Mike have told you your tiles are loose. From your description of the crunching noise, you can bet on it.

There are many other faults in your project starting with your choice of tile setter, or should I say handyman?

Jaz

EHouse · 06-14-2011, 12:03 AM

It is important to screw the subfloor into the joist. If not use ditra.

DENNIS R · 06-14-2011, 07:09 AM

Jaz,

Thanks for the reply. I have confused everyone here with two different projects. I would like to start clean with the main master bathroom and seek advice. What is the best way to recap all my facts and start over.

Yes to the joist. This is what I was told. The first floor of the addition has the joist the shorter way, 2 x 8 , span almost 10 ft, the second floor master with the stone tile is, 2 x 10, span 16, with a distance of about 10 ft with the new joist.

Thanks,
Dennis

EHouse · 06-14-2011, 08:45 AM

Forget everything and set ditra on the floor. See product specs.

JazMan · 06-14-2011, 09:21 PM

Quote:

What is the best way to recap all my facts and start over.

By starting over and recapping the facts. Then ask some questions, but not too many at a time. 3-4 max to start.

Quote:

Yes to the joist. This is what I was told.

Avoid statements like that. It give us little confidence that what you say is really true. Check it yourself.

In addition. Don't believe everything you read, such as;

Quote:

It is important to screw the subfloor into the joist. If not use ditra.

and;

Quote:

Forget everything and set ditra on the floor.

I like and use Ditra as much as possible, but those statements are silly.

Jaz

Bud Cline · 06-14-2011, 10:05 PM

Dennis let's try to clear up something. I'm not sure if what has been said is bad information or not because the guys statements are as clear as mud as are yours sometimes.

A subfloor is the panel immediately over the floor joists. Typically the panels are glued and screwed (or nailed) to the floor joists.

HOWEVER, "underlayment" is the panel that goes over the subfloor. You NEVER glue the underlayment to the subfloor and you NEVER delibertly screw the underlayment into the floor joists. The industry standard is to purposley NOT attach the underlayment to the floor joists, it is to be attached ONLY to the subfloor.

Bud Cline · 06-14-2011, 10:08 PM

I should add, that even DITRA isn't a miracle product and has its limitations. If the substrate/structure isn't right DITRA isn't going to make it right.

You CAN NOT just "forget everything" and use DITRA, that is bad advice.