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 02-21-2019, 01:35 PM   #1
richk91
Registered User
 
Join Date: Feb 2019
Posts: 15
Do I Really Need to Remove Existing Thinset Sitting on Mortar?

Hello All,

I took out the tile that was sitting on the top deck surrounding a roman tub. Exposed surface now is mortar with thinset on top. I was thinking I could leave the existing thinset in place and apply additional thinset over it to get a relatively flat surface, or apply thinset and lay ľ inch thick cement board on top and secure with durock screws. For a test, I tried drilling a durock screw into the mortar, but the screw will not bite into the mortar. Iím thinking just using thinset and cement board without screws is not a good solution. I went to a very large tile shop and was told that I should have just re-tiled over the existing tile; well itís too late for that They stated that resurfacing the deck with thinset over the existing thinset/mortar will not work for various reasons (will not be level, new tile will lift or crack, etc). They stated that I needed to remove most if not all the thinset, and resurface the mortar bed deck with Mapei Ultraflex 1 Tile Mortar with Polymer. I really donít want to remove the existing thin set for numerous reasons. Not really sure why laying thinset over existing thinset would not achieve a relatively flat surface, or maybe using a self leveling concreteÖjust thinking out loud as I type. Iím a DIY person and really would appreciate any feedback from any professional tiler. Thank you very much!
__________________
Rich
richk91 is offline   Reply With Quote
Sponsored Links
Old 02-21-2019, 01:56 PM   #2
cx
Da Home Builder
 
cx's Avatar
 
Join Date: Jul 2001
Location: Boerne, Texas
Posts: 87,226
Welcome, Rich.

I'm gonna assume that by mortar you mean a deck mud (aka dry-pack) or fat mud (aka wall mud) or similar and by thinset (a method of tile installation) you mean Portland cement-based thinset mortar, the common mortar used for bonding the tiles in the thinset method.

If so, what you can/should do would depend upon what's under the mortar, how thick the mortar is, what the condition of the mortar is, and what the condition of the existing thinset mortar is. A photo or two might be helpful.

Have the people at your tile shop seen what you have? Not sure why they'd advise removing the existing thinset mortar and then resurfacing with more thinset mortar. The resurfacing with thinset mortar is not really a recommended procedure in the tile industry, but if you were to do it I don't know just why you'd remove all the existing thinset mortar first.

Without knowing more about what you've got, my first impulse would be to tell you to remove everything down to the structure (hopefully a properly supported plywood) and install a new mortar bed, starting with a cleavage membrane and expanded metal lath, to the height you want and tile over that. The materials for deck mud or fat mud are dirt cheap and DIY labor's free, eh?

My opinion; worth price charged.
__________________
CX

Y'ALL NEW VISITORS READ THIS HERE!
cx is online now   Reply With Quote
Old 02-21-2019, 02:27 PM   #3
richk91
Registered User
 
Join Date: Feb 2019
Posts: 15
Thanks for the fast response CX! I attached a few photos for clarification on the use of mortar terminology. I really would not feel comfortable taking out the mud deck(?). I use to rely on my dad for construction/engineering help, but I'm on my own now. I have completely remodeled two bathrooms to date, so I could learn how to do a mud deck, but would prefer not going down that road if possible.
Attached Images
   
__________________
Rich
richk91 is offline   Reply With Quote
Old 02-21-2019, 03:07 PM   #4
cx
Da Home Builder
 
cx's Avatar
 
Join Date: Jul 2001
Location: Boerne, Texas
Posts: 87,226
Looks closer to fat mud to my eye, Frank, and I don't see any metal lath under it, but appears to be in good condition. Given what I see there, I'd be inclined to recommend you simply grind the thinset mortar ridges as flat as you can get them (which should be very flat) and just tile over what you've got.

My opinion; worth price charged.
__________________
CX

Y'ALL NEW VISITORS READ THIS HERE!
cx is online now   Reply With Quote
Old 02-21-2019, 03:30 PM   #5
MAPEI - Technical Service
Company Representative
 
MAPEI - Technical Service's Avatar
 
Join Date: Jul 2013
Location: Florida
Posts: 914
Hey there Rich,
I'm on board with CX's school of thought. That looks like a solid fat mud base, so clean up and flatten that existing tile mortar with a grinder and get to settin'!
__________________
Holden

http://www.mapei.com/US-EN/
MAPEI Product Tech Support Hotline 1-800-992-6273
MAPEI - Technical Service is offline   Reply With Quote
Old 02-21-2019, 05:54 PM   #6
richk91
Registered User
 
Join Date: Feb 2019
Posts: 15
CX & Holden:


That's good news! I really appreciate the both of you taking the time to read and comment on the post. I'm going to sleep well tonight, lol. Have a good evening!

rich
__________________
Rich
richk91 is offline   Reply With Quote
Old 02-22-2019, 11:42 AM   #7
richk91
Registered User
 
Join Date: Feb 2019
Posts: 15
Follow-up: While flatting the existing thinset near the back of the tub, I came across two potholes, the largest being approximate 1" X 2" X 3/8" deep. In addition, there are several minor potholes.

Question 1: Am I still good to go with using the existing mud flat?

Question 2a: Should I level these potholes out with something like a sand and topping mix such as Portland Quikrete along with an acrylic fortifier?

Question 2b: Or, just use the Mapei Ultraflex 1 as I re-tile?

rich
Attached Images
  
__________________
Rich
richk91 is offline   Reply With Quote
Old 02-22-2019, 02:07 PM   #8
MAPEI - Technical Service
Company Representative
 
MAPEI - Technical Service's Avatar
 
Join Date: Jul 2013
Location: Florida
Posts: 914
Hey Rich,

Great questions!
We don't condone using mortar to fix inconsistencies in the substrate, so the official answer would be to use a cement-based patching material to smooth out the surface before you tile.
__________________
Holden

http://www.mapei.com/US-EN/
MAPEI Product Tech Support Hotline 1-800-992-6273
MAPEI - Technical Service is offline   Reply With Quote
Old 02-22-2019, 02:45 PM   #9
richk91
Registered User
 
Join Date: Feb 2019
Posts: 15
Thanks Holden,

It's amazing on all the recommended fixes being proposed. I went out and talked to a tile contractor and he stated his company use Henry's skimcoat to repair mortar damages. I then went over to one of the big box stores and talked to the head masonry person, and he stated to use deck mud with Sika Pro Select Concrete Adhesive and Acrylic Fortifier.

I'm not a chemist and I have no idea on the various polymers/additives being used. I was told never use new stuff on old stuff i.e. mortar on mortar.

Considering my situation, small patches on a non-load bearing surface, it's probably not that big of an issue compared to someone doing a floor project.

Well, appreciate your thoughts once again.

Have a great weekend!

rich
__________________
Rich
richk91 is offline   Reply With Quote
Old 02-22-2019, 03:04 PM   #10
cx
Da Home Builder
 
cx's Avatar
 
Join Date: Jul 2001
Location: Boerne, Texas
Posts: 87,226
Rich, if it's a horizontal tile surface, it's a floor project. Someone will walk on it.
__________________
CX

Y'ALL NEW VISITORS READ THIS HERE!
cx is online now   Reply With Quote
Old 02-22-2019, 04:50 PM   #11
richk91
Registered User
 
Join Date: Feb 2019
Posts: 15
CX,

Maybe the front part yes, but that area is in good shape. The sides and back are about 5" inches wide so it would be very difficult to walk on. I'm still going to level the best I can. I was just curious what the "Best Practice" was for patching the potholes. I'm not familiar with industry standards such as ASTM, ANSI, etc for this type of work. That stated, it appears Holden concurs with cement-based patching in-lieu of mortar on mortar if I understood correctly.

rich
__________________
Rich
richk91 is offline   Reply With Quote
Old 02-22-2019, 06:26 PM   #12
cx
Da Home Builder
 
cx's Avatar
 
Join Date: Jul 2001
Location: Boerne, Texas
Posts: 87,226
There are lots and lots of cementitious patching materials out there that would be suitable for your application, Rich. MAPEI makes a couple and every other manufacturer of tile installation products makes at least one. You can also find one or more at your local home center in reasonably small containers.

Being a fella who usually has some Portland cement and some sand and sometimes some lime laying about, I'd probably just mix up a couple hands full of fat mud to fill those voids.

Lots of ways to skin that cat. You could even mix some of your thinset mortar with some sand if you don't think the Tile Ranger would find out.

My opinion; worth price charged.
__________________
CX

Y'ALL NEW VISITORS READ THIS HERE!
cx is online now   Reply With Quote
Old 02-22-2019, 07:03 PM   #13
richk91
Registered User
 
Join Date: Feb 2019
Posts: 15
Thank you CX. I'm making a big deal out of nothing apparently lol (newbie)...but just wanted to be safe because of the expense of the tiles and wanting to do things correctly.

Great site and I'm glad I came across it!
__________________
Rich
richk91 is offline   Reply With Quote
Old 02-22-2019, 07:04 PM   #14
cx
Da Home Builder
 
cx's Avatar
 
Join Date: Jul 2001
Location: Boerne, Texas
Posts: 87,226
And we want you to do things correctly, Rich. That's what this site is here for.
__________________
CX

Y'ALL NEW VISITORS READ THIS HERE!
cx is online now   Reply With Quote
Old 02-23-2019, 08:44 AM   #15
Davy
Moderator -- Mud Man
 
Davy's Avatar
 
Join Date: Jan 2003
Location: Princeton,Tx.- Dallas area
Posts: 31,039
Like Cx, I'd use what ever mud I have handy but use a little thinset first to bond the new mud to the old.
__________________
Davy

www.davystephenstile.com
Davy 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
Tile over existing cork, or remove it eblumer Professionals' Hangout 6 03-13-2013 05:45 PM
How to remove existing tile backslpash?? pnslcs Tile Forum/Advice Board 16 03-26-2008 08:36 PM
Remove Adheasive from Existing Backsplash New2Tile Tile Forum/Advice Board 2 02-25-2005 02:23 PM
How to Remove Existing Waterproof nasis Professionals' Hangout 4 09-06-2004 06:11 AM
Existing Floor - Remove? WoodLuvr Tile Forum/Advice Board 18 09-01-2004 09:00 PM


All times are GMT -6. The time now is 11:00 AM.


Sponsors

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