Porcelain Tile over Epoxy Finish

[Cotuki]

Great forum, but I'm still overwhelmed trying to determine best approach to using porcelain tile on my three-car garage floor. I apologize in advance if there are answers to these questions elsewhere in the forum:

The concrete floor is over 40 years old, with no cracks. It was well-poured and finished, with relief grooves (the contractor who built the house lived in it for 30 years). The back sections are level -- and the front sections have a gentle slope towards the entry doors. I'm near coastal California, where the ground temperature never falls below freezing. There has never been moisture wicking through the concrete.

About 4 years ago, I had the floor covered with a two-part epoxy -- done by a professional installer. I don't know the brand, but it has held up fairly well (a few chips from dropped tools, but no wear from hot tires). I don't like the floor because it's solid tan, a color that shows everything. The walls and ceilings are fully finished, so I want to switch to porcelain tile (12"x12") to really dress it up.

My question:

Do I need to remove the epoxy?? I really don't want to -- as it will be an expensive and dirty job.

I've read about Shluter-DITRA isolating polyethylene membrane, but that would add to the overall floor thickness after thin-setting under and over the membrane -- which would raise elevation issues with various walk-through doors off the garage.

Any advice would be appreciated.

Bill

 

[lane meyer]

yeah, the mortar won't adhere well to the epoxy, it needs a porous surface to work as intended.

 

[bdamico]

At the end of the day, pros will tell you to grind and they wouldn't want to be responsible for a tile job that falls apart and have seen bathroom installs over paint that have failed. There are also people here who have done what you propose and have been fine -- maybe search for Slick, I think he did it.

But if I were you, I would just reapply epoxy in the color and flake you like over what you have.

And since I doubt you will ever post again, I am talking to myself.

 

[workhurts]

And since I doubt you will ever post again, I am talking to myself.

Not sure why I find that so amusing.

Would there also be any issues with curing? I mean the water in the thinset isn't going to have any place to go other than through the tile. I can't remember for sure but isn't that why Ditra wants either the modified vs unmodified thinset (I can't remember which now or what the logic was) because of the fact that it isn't porous.

Then again if you can get thinset to stick to plastic like Ditra why can't it stick to epoxy?

 

[bdamico]

Not sure why I find that so amusing.

Would there also be any issues with curing? I mean the water in the thinset isn't going to have any place to go other than through the tile. I can't remember for sure but isn't that why Ditra wants either the modified vs unmodified thinset (I can't remember which now or what the logic was) because of the fact that it isn't porous.

Then again if you can get thinset to stick to plastic like Ditra why can't it stick to epoxy?

No clue but there have been many posts here on not being any need to use ditra for this application. I personally wouldn't worry too much

 

[Dakota00]

Then again if you can get thinset to stick to plastic like Ditra why can't it stick to epoxy?

Thinset doesn't stick to plastic... Regarding Ditra, thinset fills the voids which basically locks the tile(s) into place once the thinset cures. Which gives the impression that thinset sticks to plastic.

 

[Cotuki]

Thanks for the helpful responses. I'm going to call Shluter-DITRA and Customs, but I'm betting they'll confirm what some of you have said -- it won't adhere to the epoxy, at least well enough for them to say it's advisable.

In which case, I'll re-epoxy with darker color and flakes.

 

[Dakota00]

Using Ditra is a waste of money, if your garage floor has no cracks or movement. Besides the point, thinset still wont properly adhere to epoxy with or without Ditra on top. You need to grind the epoxy application or really rough up the epoxy finish and then skim coat a layer of thinset, let dry and then tile over.

 

[Jess]

You won't get the thinset to stick, even if you use modified. Ditra works great for wood or poor surfaces but isn't required on decent concrete. You will likely need to scarify the floor if not remove all the epoxy. I have my toolroom done in porcelain tile direct on concrete with slab heat and its great. The only issue with it is dropping objects that chip or crack the tiles. Since my area has a lathe and other machine tools, I would have done epoxy instead as the clean up would be easier. Live and learn...

Jess

 

[James-W]

Some of the members here have used VCT on their garage floor with success. I am not certain VCT will stick to epoxy, but I think it will work just fine as long as the epoxy is bonded really well to the concrete.

Anyway, assuming it will work, and depending on what you do in your garage, VCT may be an option you would want to consider. Not trying to steer you in a different direction, just offering other possible options.

 

[bdamico]

You won't get the thinset to stick, even if you use modified. Ditra works great for wood or poor surfaces but isn't required on decent concrete. You will likely need to scarify the floor if not remove all the epoxy. I have my toolroom done in porcelain tile direct on concrete with slab heat and its great. The only issue with it is dropping objects that chip or crack the tiles. Since my area has a lathe and other machine tools, I would have done epoxy instead as the clean up would be easier. Live and learn...

Jess

First I've heard of cracking due to dropped objects on this forum. I've dropped heavy *** stuff from the top of a ladder and nothing. What makes you think that wouldn't cause an epoxy to chip?

 

[Jess]

It depends what you want the floor surface for. My large bay is just concrete and I like it fine without any coating. I cut, weld and grind on that surface and it stands up fine. I used the porcelain tile because I wanted a surface that I could wipe up spills and generally keep cleaner than raw concrete. Cutting solutions, metal chips and oil get on the floor sooner or later. It works for that and looks great. I picked it over epoxy, because I could do the installation myself and used the same in other finished non workshop areas both over concrete and wood subfloors. My comment about using epoxy in the tool room comes from dropping a couple of heavy pieces of shaft cutoffs and having the sharp corner chip out a nickel sized piece. Bare concrete and epoxy would have done the same, but repair wouldn't involve chipping out the tile and resetting another one. I did solve some of the issue by placing rubber mats in front of the lathe and mill but it makes clean up of the swarf a pita. For most uses, porcelain will be easy to keep and look great.

Jess