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 07-10-2020, 09:54 AM   #1
Clarkw
Registered User
 
Join Date: Jul 2020
Location: Toronto, Canada
Posts: 2
Uneven scratch coat

Hey guys,

Homeowner in Ontario, Canada here and new to the forum. We’re undergoing a bathroom renovation and going to go with 12x24” rectified porcelain tile (9mm thickness) on the bathroom floor and bath surround.

Contractor laid down 1/2” plywood then put a metal lath and spread scratchbond 8200 on the bathroom floor. However, looks like he did not even it out or trowel it properly. Now it looks like this.

A little worried about how tile install is going to go. He said he will be doing another layer of mud to level it out as parts of the bathroom is lower than others, but I’m concerned this is not done properly. Not sure if my spidey senses are right or not.


Your advice would be greatly appreciated!
Attached Images
    
__________________
Clark
Clarkw is offline   Reply With Quote
Sponsored Links
Unread 07-10-2020, 07:22 PM   #2
smifwal
Registered User
 
Join Date: Mar 2016
Location: Kansas City
Posts: 1,389
I am not familiar with the product he used, but his process sounds suspect. And that crack doesn't boast confidence. There are products that need to have multiple lifts bit it looks like he didn't even try for smooth on the first one and now he is trying to fix his mistake. Did he use a primer? I don't want to say how he is doing it is wrong because I am not familiar with the product he is using but given the sloppy prep and the inattention to the details, I would guess the crack is from over mixing or adding too much water
__________________
Shawn
smifwal is offline   Reply With Quote
Unread 07-10-2020, 08:37 PM   #3
cx
Moderator emeritus
 
cx's Avatar
 
Join Date: Jul 2001
Location: Boerne, Texas
Posts: 90,953
Welcome, Clark.

Please add that geographic location to your User Profile so it remains permanently in view to aid in answering some types of questions. Otherwise the information will be lost before we leave this page.

That installation method, generally referred to as a Jersey Mud Job on this side of the border, is not accepted by our ANSI standards nor by the Tile Council of North America. It is generally considered a cheap way to avoid a proper installation.

But I see that product lists that as its primary and only application. I can't find any technical data on it at all as their website lists a TDS, but that link takes you to a completely different product.

I would suggest you invite your contractor to show you where TTMAC accepts that as an appropriate installation method (it may) and ask also for the Technical Data Sheet for the product.

Without knowing the product it's difficult to determine whether it's been properly installed, but it looks to me as though in parts of it far too much water was used in the mix. That would also account for the cracking.
Quote:
Originally Posted by Clark
Contractor laid down 1/2” plywood then put a metal lath and spread scratchbond 8200 on the bathroom floor.
He laid the plywood over what?

My opinion; worth price charged.
__________________
CX

Y'ALL NEW VISITORS READ THIS HERE!
cx is online now   Reply With Quote
Unread 07-10-2020, 10:29 PM   #4
Clarkw
Registered User
 
Join Date: Jul 2020
Location: Toronto, Canada
Posts: 2
Thanks CX and Shawn!

I figured it was a Jersey Mud Job based on what I have seen on this forum, but I have also read that it is apparently common here in Canada as well.

Our house was built in the 1950s so it has 45 degree diagonal plank subfloor. He put the 1/2” plywood on top of that.

Regarding the product he used (Chembond Scratchbond 8820), it looks to be a Canadian product/company that Mapei bought about 20 years ago. The technical data sheet link on the website didn’t work but i found it here:

www dot yumpu dot com/en/document/read/53832463/scratchcoat-mortar-for-metal-lath-8200-chembond

1. In any case, even if it is a Jersey Mud Job as you mentioned, shouldn’t that at least be screed? There are ridges in some areas and other areas have blobs that seem 1/8” to 1/4” thicker.

2. Wouldn’t that crack In the photo affect the performance of the thinset / tile?

I’m inclined to ask him to remove it and redo it properly as you suggested and and use something like Ditra, but I want to confirm that he will install that properly.

3. If my subfloor is not perfectly level (which the contractor has said to me), can he use a self-leveller before applying the Ditra?

4. Assuming a self-leveller is used, then would the appropriate thinset be unmodified (for both below and above the Ditra)?

Cheers,

Clark
__________________
Clark

Last edited by cx; 07-11-2020 at 08:52 AM. Reason: Light up Link
Clarkw is offline   Reply With Quote
Unread 07-11-2020, 08:59 AM   #5
cx
Moderator emeritus
 
cx's Avatar
 
Join Date: Jul 2001
Location: Boerne, Texas
Posts: 90,953
I had found that document, too, Clark. It actually reads more like a SLC product and the installation your guy us using might actually be an accepted installation method up there. But I'd still want him to show me what he's basing that upon.

The document clearly says the material is not to be used as a bonding mortar, so what you've got wouldn't technically be a Jersey Mud Job (can you have a technical category for a non-accepted method?), which beds the metal lath in thinset mortar.

In any case, it doesn't appear that the installation was done particularly well and I don't see anything in the TDS indicating that a second pour over the first is an option.

Too many questions to make me comfortable. I'd see if he can adequately defend his method.

As for the floor not being level, there is no requirement for a level surface for setting ceramic tile. The tiles require the surface to be suitably flat, but they care not a whit about level. The TDS you linked does indicate the substrate for the product must be level, but I'd tend to think that is a mistake on the part of the sales department. But if that's accurate, you couldn't use that product in your application at all. Kinda murky all around.

My opinion; worth price charged.
__________________
CX

Y'ALL NEW VISITORS READ THIS HERE!
cx is online now   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
New... Looking for Help RE: Scratch Coat NeedAnswers Tile Forum/Advice Board 16 04-09-2013 09:18 PM
scratch coat? oneraoulduke Tile Forum/Advice Board 9 10-26-2010 11:41 AM
SLC vs. 'Scratch coat' mcpuffin Tile Forum/Advice Board 3 04-21-2006 06:28 AM
Scratch coat elfederale Tile Forum/Advice Board 12 01-06-2005 11:19 PM
scratch coat tap Tile Forum/Advice Board 6 01-09-2003 09:28 PM


All times are GMT -6. The time now is 03:04 PM.


Sponsors

Powered by vBulletin® Version 3.7.4
Copyright ©2000 - 2020, Jelsoft Enterprises Ltd.
Copyright 2018 John Bridge & Associates, LLC