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
Old 12-04-2017, 05:18 PM   #1
sea_homeowner
Registered User
 
Join Date: Dec 2017
Location: Seattle
Posts: 5
Open ended tile & substrate puzzle

Hello tile and stone professionals! This website has been exceptionally informative for my husband and me in the past on such issues as "am I capable of DIYing this?" and "is my contractor doing a good job?" and "is this an insane idea that I will someday have to tear out with a crow bar?"

I finally signed up to make a project post of my own.

We tore our downstairs floors out entirely in order to do a concrete slab repair. The good news is that work is done. The bad news is we have to replace all the flooring. I paid my hardwood floor guys to put the same 3/4 in (nominal) plywood in the bathroom. The hardwood floor is 3/4 in, too, so that's the vertical space for the tile installation. We did the same bathroom-to-hardwood transition upstairs w/ditra & large format tiles and it came out really well.

I'd planned on having my tile guy do a ditra decoupling layer under porcelain tile (he did the same thing for me upstairs). Unfortunately, my subfloor needs some TLC first, and I'm not sure WHAT exactly to do with it.

There are 11/16 - 1in gaps between some of the boards, which my hardwood floor guys wouldn't fix and there is vertical distance between boards up to 1/32 in. which is not ok. I don't know how to calculate the deflection as the formulae are set up for joists, and this is plywood glued & screwed to concrete.

Ideas include:
  1. 1/4 in Hardibacker - is this going to adequately level the floor? I'm skeptical
  2. SLC w/ lathe - though from experience I know "self-level" is a misnomer and the process is not foolproof and the minimum pour thickness could be a problem
  3. Caulk or foam fill the gaps (something compressible) and roto-sand down the high plywood, and put ditra directly on that
  4. Something involving mortar... I have no experience here
  5. Tear out the newly installed subfloor and do something else entirely, like pouring SLC over concrete -- most labor intensive
  6. A product I just learned about, "HENRY 542 Liquid BackerBoard" which supposedly goes on like SLC and then acts as the substrate - typically this is used for radiant flooring but it might also solve my problems in one fell swoop

This is on-grade slab construction. The bathroom is 5ft by 5ft. I'm hiring out the ditra and/or CBU & tile work, and I need to figure out how to prep the subfloor and what to tell my tiler to do. He's proficient with either ditra or CBU, he actually prefers CBU to avoid the ditra dry time. I like ditra for the decoupling and thinness.

This is not our first bathroom subfloor, nor our first on-grade subfloor, but it is our first tile-on-grade subfloor.

Thanks everyone. I don't want to tear out the plywood subfloor I JUST paid to install, but if that's gotta happen, I'd rather do it sooner rather than later.
Attached Images
  
__________________
Trurl

Last edited by sea_homeowner; 12-04-2017 at 05:37 PM.
sea_homeowner is offline   Reply With Quote
Sponsored Links
Old 12-04-2017, 05:37 PM   #2
rmckee84
Moderator
 
Join Date: Feb 2012
Location: Southern Illinois
Posts: 2,151
I'm sorry but thats one terrible looking attempt at putting down plywood.
Alright, first things first...pull up that ply. Glued or not take it up. Then scrape the glue off the concrete. I know you don't want to hear it but its gotta go.
After that you've got a few options, pour slc and install ditra or similar. Or pull a mud bed.
__________________
Jack of most trades, master of none...
Ryan McKee
McKee Construction & Custom Tile

Last edited by rmckee84; 12-04-2017 at 07:45 PM.
rmckee84 is offline   Reply With Quote
Old 12-04-2017, 05:46 PM   #3
sea_homeowner
Registered User
 
Join Date: Dec 2017
Location: Seattle
Posts: 5
Thanks Ryan - you're right that's a shitty looking subfloor. I guess my questions become, does the subfloor looking like crap actually mean my tile install is going to be crap? I am going to hold off until we get a consensus that "rip it out" is the best option. Have you ever used a liquid backerboard? The product page makes it sound like it could solve my problems.

Edit to add: There's an old pro forum thread about ardex LBB and there's advice on gaps:

"What is the condition of the gaps between sheets? I would normally suggest a quick fill with a flat trowel using ARDEX SKM at the subfloor. Expanding foam at the perimeter is great because it seals and creates an expansion joint quickly, though you do have to be careful not to overdo it. I like using scraps strips of 1/2" foam-core building panels, wrapped with masking tape, at the doors and floor registers."

How does this idea strike you? I'll link if I'm allowed but as a new user I doubt I am.
__________________
Trurl

Last edited by sea_homeowner; 12-04-2017 at 05:55 PM. Reason: add detail
sea_homeowner is offline   Reply With Quote
Old 12-04-2017, 05:52 PM   #4
rmckee84
Moderator
 
Join Date: Feb 2012
Location: Southern Illinois
Posts: 2,151
What you have isn't salvageable. You are welcome to wait to hear others opinions but I assure you that ripping out the plywood will be the consensus for many reasons.

The plywood will being in contact with the slab, under a tile install is a recipe for potential failure on that premise alone.
__________________
Jack of most trades, master of none...
Ryan McKee
McKee Construction & Custom Tile
rmckee84 is offline   Reply With Quote
Old 12-04-2017, 06:30 PM   #5
Obo2
Registered User
 
Join Date: Dec 2017
Posts: 13
i'd try to make them fix that. They basically used some scraps they had laying around or something.

You might never know it with hardwood over the top but would probably cause problems with tile.
__________________
Nick
Obo2 is offline   Reply With Quote
Old 12-04-2017, 06:42 PM   #6
cx
da Home-builder -- Moderator-at-Large
 
cx's Avatar
 
Join Date: Jul 2001
Location: Boerne, Texas
Posts: 85,153
Welcome, Trurl.

This is not a place where you can count on consensus on anything except written industry standards, building codes, manufacturer's recommendations and such. And not always even then.

But I don't think you'll get much argument with Ryan's assessment that what you have is an absolute abomination of a plywood installation. And I doubt you'll even get a lot of argument that the whole concept of attaching plywood to concrete SOG for a ceramic tile installation is about as poorly thought out as the workmanship we see in your photo.

If you have at least 3/4" of vertical space available above the high point on your concrete floor I'd strongly recommend a bonded mortar bed for your tile installation. You can make that mortar bed exactly the correct height to allow your tile installation to be flush with your adjacent hardwood flooring if that's what you want. If you feel better with Ditra under your tile, you can do that over your mud bed, too.
Quote:
Originally Posted by Trurl
He's proficient with either ditra or CBU, he actually prefers CBU to avoid the ditra dry time.
There is no "dry time" involved in a Ditra installation except for the cure time for the mortar used to install the tile - same cure time you'd have with any other type of installation.

My opinion; worth price charged.
__________________
CX

Y'ALL NEW VISITORS READ THIS HERE!
cx is offline   Reply With Quote
Old 12-04-2017, 07:35 PM   #7
evan1968
Not So Senior Contributor
 
evan1968's Avatar
 
Join Date: Apr 2006
Location: Rochester NY
Posts: 2,209
Quote:
Originally Posted by Trurl
"is this an insane idea that I will someday have to tear out with a crow bar?"
CX and Ryan answered your question.
That's a garbage installation of that plywood. Whoever told you that plywood should be used on sog needs to be ignored for any other future advice.
The tile job is only as good as what is underneath it. This one isn't starting out very well.
__________________
Craig
Commercial Tile Installations
KEEP CALM and TILE ON
evan1968 is offline   Reply With Quote
Old 12-04-2017, 11:06 PM   #8
sea_homeowner
Registered User
 
Join Date: Dec 2017
Location: Seattle
Posts: 5
Thanks everyone. I guess I'll unscrew it, pry it up, and scrape off the glue. Shame I wasted the money on it, but it's not worth throwing good money after bad. I like the idea of a mortar bed because (a) it's old school and solid as literal rock and (b) can bring it up to whatever height I like. In this instance, the total concrete slab to adjacent-wood vertical distance is 1.5 inches, easily doable with a mortar & tile installation -- and then there's no concerns about what the plywood may or may not be doing underneath.

Y'all rock :-)
__________________
Trurl
sea_homeowner is offline   Reply With Quote
Old 12-05-2017, 07:25 AM   #9
rmckee84
Moderator
 
Join Date: Feb 2012
Location: Southern Illinois
Posts: 2,151
I really think that would be the smartest and most cost effective route. I've seen plywood installes onto a slab one time and they put a moisture barrier of plastic sheeting down first. Not to say that was the right way to handle it since the hardwood install had a failure because they didn't allow for expansion around the perimeter and the floor buckled in 4 or 5 places....
__________________
Jack of most trades, master of none...
Ryan McKee
McKee Construction & Custom Tile
rmckee84 is offline   Reply With Quote
Old 12-05-2017, 07:57 PM   #10
sea_homeowner
Registered User
 
Join Date: Dec 2017
Location: Seattle
Posts: 5
Can I ask y'all to recommend a mortar? I'm in the process of trying to find an experienced tile setter who knows his or her way around a mud bed installation, but I'm getting responses like "I'm booked out a full year" or "Maybe in June?" which has me wondering if I should make an attempt at DIYing it, if I can find a slow-enough drying mortar to work with.

I mean if I have to chisel out more concrete... at least I have the tools for it now.
__________________
Trurl
sea_homeowner is offline   Reply With Quote
Old 12-05-2017, 08:37 PM   #11
Houston Remodeler
Pondering retirement daily

STAR Senior Contributor

 
Houston Remodeler's Avatar
 
Join Date: Oct 2009
Location: Houston Texas
Posts: 27,446
All mortars cure at the same rate. You have about 4 hours from initial mixing to final installation.

There are prebagged mixes from Mapei ; 4 to 1 , and Laticrete 3701 and 249

or you can make your own. We have an entire section in our library linked in the dark blue bar above.
__________________
Paul1

For when DIY isn't such a good idea...
Houston TX area Kitchen & Bath Remodeling


http://CabotAndRowe.com
Houston Remodeler 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
Open ended Better Bench Installation 48" rangerman942 Tile Forum/Advice Board 17 06-09-2013 08:29 AM
Heated floor ended up too high. CDB Professionals' Hangout 20 02-28-2012 07:11 PM
DO NOT OPEN emails with the subject Click to Open... Bill Vincent Professionals' Hangout 10 11-29-2010 08:24 PM
Grout lines ended up wider than expected nashkato Tile Forum/Advice Board 3 03-16-2007 04:34 PM
Deck Mud Puzzle Bob Humes Tile Forum/Advice Board 7 06-02-2003 02:57 PM


All times are GMT -6. The time now is 02:34 PM.


Sponsors

Powered by vBulletin® Version 3.7.4
Copyright ©2000 - 2017, Jelsoft Enterprises Ltd.
Copyright 2014 John Bridge & Associates, LLC