Tile over Tile ?? - DIY Chatroom

Piney · 10-13-2006, 12:08 PM

Greetings--

Small bathroom remodel (4x6ft floor only).

Original tile is set over concrete floor. After several wacks with a hammer and chiisel, we determined moving it is going to be a huge pain !!

Sooooooo-- How does one go about installing new tile over old tile ?

One tile store said they would put down a layer of material (thinset of some sort) to level the existing tile, filling in the existing grout lines. Then lay thinset and new tile over this new surface.

Another store said they clean the existing tile, rough it with a sander, then just lay the new tile right over the old tile, with a slightly thicker layer of thinset (actually he used another term for a different setting material).

Comments ??

dougrus · 10-13-2006, 12:32 PM

Both suggestions are options...
First of all, you need to determine if it truly is a "concrete floor" the tile is set on...Is you house on a slab? If not then the floor you describe would be most likely a mortar bed, which may or may not be in good enough condition to tile over.
Second, although it is better not to tile over tile you can as long as you use good materials. Buy a GOOD modified thinset and either:

1. sand the surface of the old tile and lay the tile being sure to really "burn in" the thinset before you lay it with the flat side of thetrowel...in other words, make sure you get the thinset really well adhered onto the old tile, then "comb" a layer in with the notched side of the trowel. and then be sure to "backbutter" the tile before you set it....
2. "Skim coat" the original tile with thinset, let it cure, and then thinset and tile over that after...the point is to level off the surface for the tile...

I have done a couple tile over tile jobs...one in my house and one in my dads house...I just sanded the surface well and then just layed the tile...ALthough, If your floor is bumpy and has minor dips you can fill them with a skim coat.

BY THE WAY....NEVER USE SO CALLED PRE-MIXED THINSET OR MASTIC TO SET FLOOR TILE. No matter what a home shmeepo worker says.

Hope that helps....

J187 · 10-13-2006, 02:39 PM

Piney, I very recently tiled over the old tile in bathroom. Two things to definitley consider

1. is the existing tile in good shape, are in any tiles loose?
2. how will the new height effect the room, ie you will probably need to extend the closet flange for the toilet, maybe cut the bottom of doors, raise vanities, and account for a new height difference at the transition point between the room and the hall.

I recently tiled over my old tile which was in perfect condition. I hope you didn't do any damage when you first tried to remove the old. I used a nice modified thinset and simply cleaned and scuffed the old tiles, applied my thinset like usual and tiled. I strongly recomend you get your tiles and thinset from a tile store rather than a big box home improvement store. The stronger tiles and better thinset will greatly aid your project.

LanterDan · 10-13-2006, 02:45 PM

If you did decide to take another crack at removing the old tile, I have heard (although not personally tried) that those air chisles that you can buy for under $20 work very well for this. This does require to you to have, or be able to borrow, an air compressor. Try to chisel underneath a tile and pop it up. Getting it started so you can do this will probably be the hardest part.

J187 · 10-13-2006, 02:48 PM

If its a mortar bed, you'd have to be willing to do some work to that after removing the tiles, chances are pretty good something will need to be done. You may have better luck just going right over the old. If the old tiles are solid, its perfectly fine.

dougrus · 10-13-2006, 02:50 PM

Agreed on all points....

Changing all the heights can be a pain. Toilet flange you can get a flange extender but for thresholds and door casings, you have to do some cutting and/or removing.
Make sure you email back and let us know what is really under the floor and what condition the tiles are now in...As J187 said, tiling over a solid, non-moving floor is essential.
HD does have crappy tiles so go to a tile store as J187 said...
Although if you do need to buy modified thinset from there for whatever reason, the Versabond is a very good modified thinset.

dougrus · 10-13-2006, 02:55 PM

If it IS a mortar bed it would be somewhat difficult to get that tile up without cracking or damaging the bed and then, likely you will be looking at some serious demo to get that floor up...Ive done it a few times and it is no picnic.

Piney · 10-13-2006, 04:57 PM

Greetings--

Thanks for all the advise--

== The original tile IS on concrete slab flooring, as is the rest of the house.

== The original is definitely STUCK well-- none loose and quite difficult to chip loose. I tried this on a tile that would go under a new vanity-- no way its coming up with even moderate force.

Regarding problems with the additional height-- I can add an extension to the toilet flange. We're replacing the vanity anyway so that's not an issue.

DecksEtc · 10-20-2006, 11:41 PM

Quote:

Originally Posted by LanterDan

If you did decide to take another crack at removing the old tile, I have heard (although not personally tried) that those air chisles that you can buy for under $20 work very well for this. This does require to you to have, or be able to borrow, an air compressor. Try to chisel underneath a tile and pop it up. Getting it started so you can do this will probably be the hardest part.

An air chisel works well for this type of problem. It's a slow process but it does work.

dre2142 · 10-22-2006, 12:03 PM

Getting under the 1st tile is the hardest part. After that, if you get under the tiles and theyll all pop up....once we got to that point, we realized taht if we went down to the bottom, an entire portion would pop up all at once.

Lucky for us, we had this at our disposle.

Piney · 12-10-2006, 09:27 PM

Greetings--

I"ve been able to get most all of the vinyl adhesive off via scraping and paint thinner and elbow grease (and a little

)

Folks have said to sand the tile so that the new adhesive/mastic will stick to it under the new tile.

QUESTION-- About sanding. I took my belt sander and put on a #80 belt rated for tile/cement. It dulled the surface some, but not a lot IMO.
How much of a rough surface is needed ?
Should I use a grinder or something similar ?

QUESTION-- About cleaning. I used paint thinner to dissolve the glue. How clean does the tile surface need to be.
Should I go over the surface with some other cleaner ?

THanks !!