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 05-26-2017, 07:58 AM   #1
speed51133
Registered User
 
Join Date: May 2017
Location: Milwaukee WI area
Posts: 1,073
Basement tile question re-substrate transitions

I am tiling the concrete floor in my basement. It is a modern home with radiant heat. The concrete has thick poly under it as well as 2in of foam insulation. No moisture issues anywhere. Sump never runs. 2 walls are exposed as well.

I am going to tile the sliding, walk-out door area. The issue is that there is the "sill plate" of pressure treated lumber under the sliding door. It extends into the basement floor about 3 inches. So my flooring is basically concrete with a perimeter of pressure treated lumber (this is only true at the door threshold).

I am planning of using Ditra for any tile on the concrete. I am also planning on using Schluter Dilex (Schluter's expansion joint) wherever there are saw cuts in the concrete floor. Do I really need the Dilex?

What about this pressure treated lumber area? Can I just put the Ditra over it? Do I need to use a threshold transition here (line an aluminum piece) and not tile that area?

Thanks!
__________________
Mike
speed51133 is offline   Reply With Quote
Sponsored Links
Unread 05-26-2017, 08:38 AM   #2
rmckee84
Moderator
 
rmckee84's Avatar
 
Join Date: Feb 2012
Location: Southern Illinois
Posts: 3,015
1. Its up to you, a joint honoring saw cuts would be the most efficient way to handle them. Some antifracture membranes claim you can span saw cuts if you follow their directions. You must have the appropriate number of soft joints for your installation and allow for perimeter expansion regardless.

2. You could try to just ditra over it and hope for the best, but PT lumber is one of the worst things you could install over add in the change from one surface to another and chance for success goes down even more. I would be inclined to put something other than tile over it. The other option would be to have a soft joint there at the transition so it could move independently from the rest of the installation. Even then its hard to say what the success of the tile in that small area will be.
__________________
Jack of most trades, master of none...
Ryan McKee
McKee Construction & Custom Tile
rmckee84 is offline   Reply With Quote
Unread 06-01-2017, 07:59 AM   #3
speed51133
Registered User
 
Join Date: May 2017
Location: Milwaukee WI area
Posts: 1,073
first time ditra setter here...

My substrate is concrete and it is dry. Thick poly and foam insulation under the slab. Dehumidifier set to 55% and slab kept at 70 degrees with hydronic heat.

I wet the concrete with a wet mop, then wiped with a wet sponge. I mixed the thinset (unmodified) to the consistency of runny pancake batter. I also applied thinset using the NON notched side of the trowel to first press it into the concrete. I then used the Schluter recommended 1/4in x 3/16in V notched trowel.

Let me tell you, pressing the ditra into this thinset DID NOT result in a good bond with the fleece. Peeling back the ditra showed a grid like pattern of bonding thinset with checkered dry patches of fleece. I reapplied the thinset with added water so it was very runny, but still held a notch. This helped, but not to the point where the fleece was totally covered with wet thinset when peeled back.

I ended up adding thinset with the notched trowel by not scraping the concrete very hard at all, like barely touching it, leaving the thinset rather thick. This helped as well to get like 75-85% of good bonding evidenced by saturated fleece.

I said good enough. This was just a small section of ditra about 4x7ft in size for a door entryway.

I was planning on getting a 1/4in x 1/4in square notched trowel to do the rest and mixing the thinset very runny. I had to re-read the Schluter instructions 10 times to make sure they recommend that size trowel (1/4in x 3/16in V notched). They actually recommend three, yes THREE, different sizes and do not say which one is better or why use one over the other. They do recommend different sizes for ditra XL, but I am not talking about that.

What do you guys think?
__________________
Mike
speed51133 is offline   Reply With Quote
Unread 06-01-2017, 03:07 PM   #4
cx
Moderator emeritus
 
cx's Avatar
 
Join Date: Jul 2001
Location: Boerne, Texas
Posts: 90,753
Welcome, Mike.

I moved your post here to your project thread for continuity. We can give the thread a more generic title any time you'd like to suggest one.
__________________
CX

Y'ALL NEW VISITORS READ THIS HERE!
cx is online now   Reply With Quote
Unread 06-01-2017, 03:20 PM   #5
speed51133
Registered User
 
Join Date: May 2017
Location: Milwaukee WI area
Posts: 1,073
thanks...thought I was going crazy!
__________________
Mike
speed51133 is offline   Reply With Quote
Unread 06-01-2017, 03:24 PM   #6
cx
Moderator emeritus
 
cx's Avatar
 
Join Date: Jul 2001
Location: Boerne, Texas
Posts: 90,753
Schluter makes a Ditra trowel (well, they cause it to be made) that is what I'd recommend for the purpose. You can use any of the other recommended sizes and all of them will work if you're doing everything correctly.

Quote:
Originally Posted by Mike
I was planning on getting a 1/4in x 1/4in square notched trowel to do the rest and mixing the thinset very runny
Whatever trowel you elect to use your mortar must still be mixed within the water recommendations of its manufacturer and must be able to hole a notch when troweled. You never want your mortar "very runny" when setting anything.

My opinion; worth price charged.
__________________
CX

Y'ALL NEW VISITORS READ THIS HERE!
cx is online now   Reply With Quote
Unread 06-02-2017, 09:26 AM   #7
speed51133
Registered User
 
Join Date: May 2017
Location: Milwaukee WI area
Posts: 1,073
yeah, i would still mix it so it holds the notch, but really toe-ing that line where it is too runny. Maybe my unmodified is just kind of crappy? Im mixing it with a 3/4in drill and paddle mixer in a 5gal bucket....
__________________
Mike
speed51133 is offline   Reply With Quote
Unread 06-02-2017, 11:38 AM   #8
rmckee84
Moderator
 
rmckee84's Avatar
 
Join Date: Feb 2012
Location: Southern Illinois
Posts: 3,015
If you have more ditra to put down do yourself a favor and pick up a bag of laticrete 254, you won't have any issues with that mat staying down. Wear old clothes and keep it off stuff you don't want thinset on because 254 is some serious stuff.
__________________
Jack of most trades, master of none...
Ryan McKee
McKee Construction & Custom Tile
rmckee84 is offline   Reply With Quote
Unread 06-02-2017, 11:44 AM   #9
speed51133
Registered User
 
Join Date: May 2017
Location: Milwaukee WI area
Posts: 1,073
but the 254 is polymer modified...

not supposed to use that
__________________
Mike
speed51133 is offline   Reply With Quote
Unread 06-02-2017, 01:26 PM   #10
rmckee84
Moderator
 
rmckee84's Avatar
 
Join Date: Feb 2012
Location: Southern Illinois
Posts: 3,015
Yes I understand that. All I can say is schluter is the only company that has the modified/unmodified limitations. If you really feel you're going to need the warranty someday then by all means stay within the lines and adhere to their specifications. But I can tell you that using 254 under your mat will give you everything you're looking for while using the suggested trowel size. If you go up to a 1/4"x1/4" you may find you'll end up pushing around a bunch of material under the mat causing humps and low spots.
__________________
Jack of most trades, master of none...
Ryan McKee
McKee Construction & Custom Tile
rmckee84 is offline   Reply With Quote
Unread 06-06-2017, 07:59 AM   #11
speed51133
Registered User
 
Join Date: May 2017
Location: Milwaukee WI area
Posts: 1,073
I ended up sticking with the recommended trowel. I finally got the Kerdi to bed in well with the non modified.

I wet mopped the concrete like 3 times until it stayed dark for a few minutes without drying. I also mixed the thinset real wet (but still held trowel lines).

The thinset I am using is found here: http://tileperfect.hbfuller-cp.com/node/3 looks like it is made by the parent company that owns TEC.

I have not seen it sold, talked about, or anything anywhere. It looks like it is a private label sold exclusively in HOBO stores (home owners bargain outlet). This place is like a TJ Max of hardware stores. They get all the old stock and overflow that wont move. You can get decent tile for like 1-1.50 a sqft (including real stone). You just have to buy it all up the second it hits the floor.

The thinset may be junk, but I got it working OK.

You know, I have read people complaining that non modified wont stick to the ditra (on the top side). Well, isnt that the whole point? You wouldn't have uncoupling if it did stick to the ditra. My plan was to go ahead and continue using unmodified to set the tile.
__________________
Mike
speed51133 is offline   Reply With Quote
Unread 07-12-2017, 01:07 PM   #12
speed51133
Registered User
 
Join Date: May 2017
Location: Milwaukee WI area
Posts: 1,073
Project done!

Thanks all for your help. Attached are pics of the original issue and the progress.
Attached Images
     
__________________
Mike
speed51133 is offline   Reply With Quote
Unread 07-12-2017, 03:14 PM   #13
Captain Kana
Tile Contractor and Advisor
 
Join Date: Jul 2017
Location: Aptos, CA
Posts: 7
Smile Unmodified/Modified Thin Set Ditra Installation

I am not sure if I am reading the above comments right. You can use any modified thin set to bond Ditra to the substrate (plywood, concrete, etc.), or Schulters thin set.

Unmodified thin set is used to bond the tile to the Ditra. It creates a mechanical bond. You can also use Schluters thin sets again.

Page 4 of the installation handbook.

I have around 1000 feet of slate installed over decks, stairs, and car ports using Ditra, love it.

Dan C.
__________________
Dan
Captain Kana is offline   Reply With Quote
Unread 07-12-2017, 04:43 PM   #14
cx
Moderator emeritus
 
cx's Avatar
 
Join Date: Jul 2001
Location: Boerne, Texas
Posts: 90,753
Welcome, Dan.
Quote:
Originally Posted by Dan
You can use any modified thin set to bond Ditra to the substrate (plywood, concrete, etc.), or Schulters thin set.
Not necessarily.

Schluter recommends a thinset mortar suitable to the substrate over which the Ditra is to be installed. For concrete, you'll find them recommending un-modified mortar (A118.1). For plywood or OSB they'll recommend a modified thinset mortar meeting A118.11 as is the requirement of the tile industry. Over some other substrates you'll find them deferring to the substrate manufacturer, such as with gypsum substrates.

And now, of course, that they have their own line of bonding mortars, they'll recommend one of them by name in most applications.

Everyone else in the industry will recommend a modified thinset mortar on both sides of their "uncoupling" membranes.
__________________
CX

Y'ALL NEW VISITORS READ THIS HERE!
cx is online now   Reply With Quote
Unread 07-13-2017, 10:12 AM   #15
Captain Kana
Tile Contractor and Advisor
 
Join Date: Jul 2017
Location: Aptos, CA
Posts: 7
Thanks for the clarification. I must remember to read all the way through the installation guides.

Dan C.
__________________
Dan
Captain Kana 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
KERDI / Tile / Substrate question... tilenewbie Tile Forum/Advice Board 12 01-04-2017 06:02 PM
Substrate Question kblack583 Tile Forum/Advice Board 9 05-22-2014 02:08 PM
Substrate question DumbFarmer Tile Forum/Advice Board 6 02-24-2011 10:34 PM
Yet another substrate question... alfadoc Tile Forum/Advice Board 5 06-25-2009 10:29 AM
Substrate in basement AnnieL Tile Forum/Advice Board 27 10-30-2007 02:32 PM


All times are GMT -6. The time now is 10:57 PM.


Sponsors

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