Ceramic Tile Advice Forums - John Bridge Ceramic Tile

Welcome to John Bridge / Tile Your World, the friendliest DIY Forum on the Internet


Advertiser Directory
JohnBridge.com Home
Buy John Bridge's Books

Go Back   Ceramic Tile Advice Forums - John Bridge Ceramic Tile > Tile & Stone Forums > Tile Forum/Advice Board

Sponsors


Reply
Thread Tools Search this Thread
Unread 10-02-2019, 07:50 AM   #1
MIke G
Registered User
 
Join Date: Oct 2019
Location: Cincinnati, OH
Posts: 28
Kitchen Remodel - Floor Issue

OK, looks like my registration and post around the time of the crash were lost, was finally able to re-register.

Looking at a kitchen remodel and would like to tile the floor. Kitchen is roughly 10 x 22. 8" nominal joist with an 11 foot span, 16" OC. Joist look like yellow southern pine. Calculator says OK for tile. Wife has picked out a "quilt like" pattern using large (20 x 20) and small (12 x12) with rectangles and smaller still squares. However....

The floor, which has 3/4" plywood over the joist has 5/16" thick parquet glued directly to the plywood (i.e. no underlayment). Trust me, it ain't coming up as I learned when I installed 3/4" oak flooring in hallway. I even rented the machine with the blade in front, all it did was tear up the plywood. Ended up cutting it out and replacing with new plywood. Obviously, to replace subfloor in kitchen is a big job.

In the powder room off the hallway, I simply put backer board (screwed) over the parquet and tiled over it with 12" sq tiles, no issues/cracking over 10 years, but the room is only 5 x 5.

So, anyone think this is a reasonable approach for this kitchen? Another option might be to use Ditra underneath.

I've done a number of tiling projects, but this would be the largest area by far. A couple of photos of existing floor for info.

Thanks, Mike
Attached Images
  
__________________
Mike

Last edited by MIke G; 10-02-2019 at 08:00 AM. Reason: Photos did not attach
MIke G is offline   Reply With Quote
Sponsored Links
Unread 10-02-2019, 08:18 AM   #2
cx
Da Home Builder
 
cx's Avatar
 
Join Date: Jul 2001
Location: Boerne, Texas
Posts: 88,431
Welcome, Mike.

Sorry you got lost in the great server shuffle.

I think the CBU would be the safer approach over the wood parquet if it can't be removed. That would presume the CBU was properly mechanically attached over a bed of thinset mortar as required, of course, and that the fasteners extended through the subflooring. There is certainly a danger that the mortar could seriously compromise the parquet, depending upon the actual makeup of the parquet and the bonding/sealing of that flooring when it was installed. You'll not find any such recommendation from any of the CBU manufactures, of course, and you can view my warranty information below.

I would not recommend any sort of membrane, such as Ditra, that was attached to the parquet flooring with thinset mortar.

My opinion; worth price charged.
__________________
CX

Y'ALL NEW VISITORS READ THIS HERE!
cx is online now   Reply With Quote
Unread 10-02-2019, 08:24 AM   #3
MIke G
Registered User
 
Join Date: Oct 2019
Location: Cincinnati, OH
Posts: 28
CX,

Thanks for the quick reply.

Tried searching to figure out what CBU is? Cement board?

If so, my plan would be 1/4" (or maybe 1/2" would be better?) over the parquet, level as needed, install tile. Backer board screwed thru to plywood subfloor (but not joist, correct?).
__________________
Mike
MIke G is offline   Reply With Quote
Unread 10-02-2019, 08:40 AM   #4
cx
Da Home Builder
 
cx's Avatar
 
Join Date: Jul 2001
Location: Boerne, Texas
Posts: 88,431
Yes, CBU is Cementitious Backer Unit, the technical designation for such products (ANSI A118.9). Cement board in the vernacular.

No reason to use the thicker CBU unless you just need to raise the height of your finished floor. All manufacturers of such products recommend their thinner material for floor applications.

Yes, fastening to the subfloor, but not the joists, is the usual industry recommendation for tile underlayments.

My opinion; worth price charged.
__________________
CX

Y'ALL NEW VISITORS READ THIS HERE!
cx is online now   Reply With Quote
Unread 10-02-2019, 09:56 AM   #5
MIke G
Registered User
 
Join Date: Oct 2019
Location: Cincinnati, OH
Posts: 28
CX,

OK, got it.

Typically, you would put thinset between the subfloor (parquet in this case) and the 1/4" backer board, correct? I guess the question in my mind is this better or worse, than thinset on exterior grade plywood which I've done in the past with no issues.

I do need to look at the height of the floor as there is mismatch at the door way to the hall and DR to see what I need.

Also, wife is looking at what I call a quilt pattern of tile using 20 x 20, 13 x 13, 7 x 7 and rectangles (7 x 20 maybe). Any tile size limitations I need to consider for this floor.

Thanks again.
__________________
Mike
MIke G is offline   Reply With Quote
Unread 10-02-2019, 02:45 PM   #6
cx
Da Home Builder
 
cx's Avatar
 
Join Date: Jul 2001
Location: Boerne, Texas
Posts: 88,431
The thinset mortar under the CBU is for the purpose of filling any voids and providing a 100 percent footprint, Mike, not for bonding. The mechanical fasteners hold it down, the mortar holds it up.

Putting thinset mortar on exterior glue plywood (there is no exterior grade) doesn't harm the plywood, but you don't know what glue might have been used on that parquet flooring. That's my concern there.

Major consideration on your tile size is the flatness of the substrate for the larger tiles. Industry standard calls for no deviation from intended plane of more than 1/8th" in ten feet nor 1/16th" in two feet. That's a very, very flat floor.

My opinion; worth price charged.
__________________
CX

Y'ALL NEW VISITORS READ THIS HERE!
cx is online now   Reply With Quote
Unread 10-03-2019, 07:35 AM   #7
MIke G
Registered User
 
Join Date: Oct 2019
Location: Cincinnati, OH
Posts: 28
CX, sorry for the delay here, the site wouldn't let me log on for some reason.

Maybe I misunderstood a bit, here is my latest thoughts.

I need a min of 1.25" of subfloor thickness, adding 1/4" of cement board will get me there; however, in addition, by using thinset under the cement board I will effectively level the floor as my memory says cement board doesn't bend/flex much. Right now the floor has some valleys/dips that are too big so some leveling will be needed.

I looked at the parquet and realized each quadrant is made up of solid strips of oak that are, I believe, glued together, so the effect of thinset on this glue is a question.

Thanks for all the input.
__________________
Mike
MIke G is offline   Reply With Quote
Unread 10-03-2019, 11:53 AM   #8
speed51133
Registered User
 
Join Date: May 2017
Location: Milwaukee WI area
Posts: 716
I would not consider the thinset mortar to be a leveling agent for dips. It is for smaller stuff like indentations from screws, chips, cuts, and grain irregularities in the wood. The thinset mortar is troweled on evenly in even thickness with a notched trowel to get a very uniform and 100% coverage on the floor. NOT blobs here and there and NOT more in some areas to fill in dips.

If you have dips and valleys in the floor, I would use a leveling compound or SLC and let it cure FIRST.
__________________
Mike
speed51133 is offline   Reply With Quote
Unread 10-03-2019, 03:21 PM   #9
cx
Da Home Builder
 
cx's Avatar
 
Join Date: Jul 2001
Location: Boerne, Texas
Posts: 88,431
I'm gonna agree with Mike (51133) that thinset mortar is not the proper material to use for leveling or flattening the substrate and the tile industry and thinset mortar manufacturers will also agree. But I'll disagree on where you should do your flattening and leveling.

If you plan to use a CBU as your tiling substrate, you want to do all your flattening and leveling on top of the CBU. While properly installing the CBU over a bed of mortar may help even out some of your subfloor irregularities, you'll want to do any further leveling or flattening after the CBU is installed.

My opinion; worth price charged.
__________________
CX

Y'ALL NEW VISITORS READ THIS HERE!

Last edited by cx; 10-03-2019 at 05:19 PM. Reason: Typo
cx is online now   Reply With Quote
Unread 10-03-2019, 05:12 PM   #10
MIke G
Registered User
 
Join Date: Oct 2019
Location: Cincinnati, OH
Posts: 28
Mike, got it, use leveling compound.

CX, Mike, struggling with my comfort level on placing tile over this. Although the parquet is solidly glued down and although wet occasionally over the past 22 years with no issues, I'm struggling getting past the risk of doing this job and having problems down the road. The approach of screwing down current floor to joist, leveling, then adding 1/4" CBU is risky if the thinset mortar were to mess up the parquet glue in my mind.

As distasteful as it is, pulling out the saw and cutting it out and replacing with new 3/4" plywood and additional plywood/CBU to get to the height I need is probably the sound choice. But, ugh.....
__________________
Mike
MIke G is offline   Reply With Quote
Unread 10-03-2019, 05:26 PM   #11
cx
Da Home Builder
 
cx's Avatar
 
Join Date: Jul 2001
Location: Boerne, Texas
Posts: 88,431
Quote:
Originally Posted by Mike
The approach of screwing down current floor to joist, leveling, then adding 1/4" CBU is risky if the thinset mortar were to mess up the parquet glue in my mind.
Again, Mike, you would not do any leveling before installing the CBU. You must do any flattening or leveling after installing the CBU.

I would suggest you cut a piece or two of CBU maybe a foot square and install it somewhere out of the way on your floor for a week and then remove the squares. I wouldn't bother with the mechanical fasteners, just set a 5-gallon bucket of water or sand or similar on the square to force it into the mortar a bit and leave it alone. When you remove the test square(s) you'll know immediately if any significant damage has been done to your parquet floor and either eliminate that installation method as an option or give you confidence in the method in your application. Might work just fine. Might not.

My opinion; worth price charged.
__________________
CX

Y'ALL NEW VISITORS READ THIS HERE!
cx is online now   Reply With Quote
Unread 10-03-2019, 06:41 PM   #12
MIke G
Registered User
 
Join Date: Oct 2019
Location: Cincinnati, OH
Posts: 28
CX,

Good points, leveling on top of CBU. Will consider the proposed test.
__________________
Mike
MIke G is offline   Reply With Quote
Unread 10-04-2019, 07:31 AM   #13
speed51133
Registered User
 
Join Date: May 2017
Location: Milwaukee WI area
Posts: 716
I would go with whatever CX says, but I don't understand why you would NOT want the wood floor level before screwing CBU down.....
__________________
Mike
speed51133 is offline   Reply With Quote
Unread 10-04-2019, 08:01 AM   #14
MIke G
Registered User
 
Join Date: Oct 2019
Location: Cincinnati, OH
Posts: 28
Guys, thanks for the great info, glad I found this site. Not glad about the parquet, but I've got some time to think it over.
__________________
Mike
MIke G is offline   Reply With Quote
Unread 10-04-2019, 08:02 AM   #15
Carbidetooth
Hmmmmm
 
Carbidetooth's Avatar
 
Join Date: Mar 2010
Location: Boise, ID
Posts: 1,413
I suspect he's considering that most patching material is cementitious and in small, thin patches is high in compressive strength, but will crack when screws are driven through it. Thus the integrity is compromised. Think peanut brittle.
__________________
Peter

Silicone (not silicon) Sealant Ranger
Carbidetooth is offline   Reply With Quote
Reply

Stonetooling.com   Tile-Assn.com   National Gypsum Permabase


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Kitchen remodel - Sub-floor windgate98 Tile Forum/Advice Board 1 09-26-2018 09:12 PM
Kitchen Floor Remodel dmill8023 Tile Forum/Advice Board 3 08-03-2018 01:05 PM
Kitchen Floor Issue Gracie714 Tile Forum/Advice Board 4 03-24-2009 04:43 AM
Kitchen Floor Remodel Amateur_Dave Tile Forum/Advice Board 6 02-02-2006 09:42 PM
Kitchen floor remodel nochins Tile Forum/Advice Board 4 09-25-2002 07:04 PM


All times are GMT -6. The time now is 12:16 AM.


Sponsors

Powered by vBulletin® Version 3.7.4
Copyright ©2000 - 2019, Jelsoft Enterprises Ltd.
Copyright 2018 John Bridge & Associates, LLC