Cutback revisited [Archive] - Ceramic Tile Advice Forums - John Bridge Ceramic Tile


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07-29-2001, 01:26 PM
I was all ready to everybody's tips and use modified thinset over the cutback on my concrete floor. Then, John said to scrape up any areas that were flaking. Got me to thinking about removing the cutback again. So, I tried a little paint thinner on a spot and it turned into jelly and scraped up pretty easily.
Are there substances that should definitely not be used (including for safety reasons)? Should I stop fooling around and just go over the cutback? What would you do?
Somebody stop me before I try to clean the floor (11' x 23')!

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Rob Z
07-29-2001, 02:26 PM
Allright, I just sent in a reply...where is it?

Oh well...

Don't use solvents on the concrete, they can affect the bond of the thinset later.

Clean and scrape the floor and use a good, latex modified thinset. (I used a floor scraper with water to keep the dust down. Then used the wet/dry vac to suck up the mess). John tells me that he has been going over this stuff for years without any problems. I just did a floor over cutback because of John's info. I had been passing on thses jobs because I thought they shouldn't be done.

Is it an ideal surface? No. But I think the CW is that you can do it.

John Bridge
07-29-2001, 02:32 PM
I fielded your reply in mid-air. No, I didn't.

Okay, here's the John Bridge theory on cutback. I think trying to remove it with solvent gains you nothing, becase as Rob said, it just seals the floor, which is what you have now. Scrape it to remove anything loose and go for it.

There is no ideal surface for ceramic tile (except maybe a well-constructed floating mud bed).

Go for it.

07-29-2001, 02:41 PM
Okay, Coach!

07-29-2001, 03:16 PM
Get as much as possible up first, Try to get it to a film if possible, Your chances of it wicking and having a bad bond will be much reduced.No chemicals of anykind it will just coz more problems.
Do not sand it either.
Make sure ahead of time is it actually cutback and not tar, there is a differance.

There are better and more expensive ways for removal like Dry-ice blasting etc.. but like John said it is not the perfect substrate but you should be fine without these.
Use a high quality polymer-modified thin-set also for better bond.

Bud Cline
07-29-2001, 10:04 PM

There you go with the dry ice thing again. Don't waste your money man. Your on the right track otherwise I think and I do what John does, scrape what I can and GO FOR IT. Why worry about cut back wicking? Wheres it going to wick to?

And Rob, I've been doing this for years and I think it works, the only reason I think that, is because I have never had a failure doing it.

07-29-2001, 10:46 PM
Can't help it Bud, I want one of those fancy machines. Just yesterday I was trying to clean my throttle bodies in my Z and wished I had one. one of these days. they are about $10,000 for a portable.
Wicking is known with all portland products, high moisture and the right conditions(not scraped).
I have never seen a cutback ceramic failure either or wicking but they say it happens so who am I to disagree.
Now I have seen wicking in portland patches and how it will yellow vinyl floors but never in tile...yet.

07-29-2001, 10:56 PM
Did'nt mean to scare ya. Like Bud and John said you will not have problems it is done all the time without problems.

Bud Cline
07-29-2001, 11:02 PM
Visible thru cement and gyp patches: ABSOLUTELY
Visible thru vinyl sheet goods: YES,
Visible thru some marbles: POSSIBLY,
Ceramic tile: HOW?

07-30-2001, 07:07 AM
So, what's the difference between cutback and tar?

John Bridge
07-30-2001, 03:46 PM
I'm sorry for the confusion, Zel.

There is no appreciable difference. And you would not have tar on the floor. You have cutback.

To the pros: Please control yourselves. Technical discussions belong on the other board. We are trying to aid these people in getting their projects done.

Bud Cline
07-30-2001, 04:12 PM
Yeah JC, what the hells the matter with you? You started and now you got me in trouble, I'm gonna tell my mom.

Sorry John.

John Bridge
07-30-2001, 04:29 PM
No trouble, amigo. But you guys were confusing ME.

07-30-2001, 05:49 PM
Ok np

Rob Z
07-30-2001, 06:18 PM
OK guys, stop the trouble making, or John is going to send everyone to their room.

Zel, don't stress over this. Clean the floor. Mop it. Shop Vac it. Set the tile with quality thinset. Use the right trowel. Concentrate on your lay out. Grout it. Read the mixing instructions on the bags of materials and let the stuff slake. You can do it. Check your layout lines frequently.

Send us pictures when you're done.

Do you have John's book? When you're done, John can autograph it for you. (the book, not the floor)


[Edited by Rob Zschoche on 07-30-2001 at 09:31 PM]

07-31-2001, 06:53 AM
Okay, already! I'm going to try start on it this weekend. We've got the room mostly cleared out--what I'm going to do with that refrigerator, I don't know.
Boy, I feel like I'm causing trouble within the gang.
You guys are the best. At what, I'm not sure ...

07-31-2001, 07:36 AM
No trouble just sparking theoretical debate is all.goodluck let us know how it turns out.

01-01-2005, 09:09 PM
About 15 years ago my neighbor had ceramic tiles put on his floor. Since then his house sold several times. Recently the present owner showed me that one of the tiles had come up. I recognized the black stuff on the concrete floor beneath it as the residue of the same "cutback" adhesive that was used to stick the linoleum tiles to my concrete floor when my house was built. Obviously the tile adhesive used by the person who installed the tiles in my neighbor's house didn't stick to the cutback. Since the adhesive manufacturer's claims can't be trusted the only way to be sure that tiles will stay stuck to the floor is to remove everything down to the bare concrete and use ancient and proven tile methods and materials to lay down the tiles. See my post

for details of how I removed the cutback from my concrete floor.

- ChrisB

09-21-2009, 09:50 AM
Not sure if this can or will help anyone, but I recently bought a 90 year old house. The entire house had beautiful wood floors, but the 21 x 14 kitchen had some UGLY laminate adheared with our wonderful friend, cutback. I used a wallpaper steamer to soften the laminate and cutback, which makes it easier to just scrape right off. The cutback is wet, so if it does contain asbestos, it does not become friable, so it is not inhaled and is safer. It is also safer than nasty chemicals. I am so very happy that I get to save my wood floor!!

I have written all about my expeirience with this on my blog but I'm not sure I can posts links here.

I am not done yet, as I am working only a few hours a night, but should be done this week and post pics of the finished floor.

I really hope this can help someone out. :goodluck: