One of the things never tried is doing granite tile over formica. Never even done tile before but DIL wants black tile.
Figure rough sanding the existing formica countertop and scratching it up well would be as good a base for tile base as backerboard. Definetely water resistant.
Any experience on this? Any special primer (there seems to be a special primer for almost anything) recommended for going onto formica used as a tile base?
Replies
as easy as it would be to screw 1/4 cement board down onto the formica i wouldn't take the chance. then you know your ready to go. larry
hand me the chainsaw, i need to trim the casing just a hair.
Custom Building Products makes a high bond thinset called "mega-flex". I have used it in the past to install new tile over the top of existing tile with success but have never tried it over formica. You could run a test in a small area to see if it will bond. Otherwise, I suggest removing the formica and installing plywood and backer-board.
In the 8 years that have passed since this was posted, perhaps there is more experience with tiling over Formica. Here's the story (a long one):
Our last house had mass production Formica countertops that were "supposed" to look like butcherblock. Maybe they did in the dark. I eventually replaced the countertops, but when it was time to move we bought a house with the exact same Formica. I hate it (the Formica, not the house)! A friend used granite tiles in his kitchen and they cost less and looked pretty good. My wife liked it too and I should send the friend a present for the money he has saved us.
Formica is an excellent countertop—forgiving when you drop something, no maintenance and newer styles look very good. But I have done a lot of tile and don't want to deal with some kind of slab or the money that goes with it. I suppose I could learn to use sheet Formica, but I am better with tile work than learning a new skill and being afraid of the result.
We have switched to porcelain—perhaps polished or even a matte finish. The reason—no maintenance except for grout, we can get bullnose in porcelain but not granite (less work for me) and more variety. Granite tends to to be either a nearly solid black or lots of circles or other patterns not too appealing to me. We saw some greyish colors and designs that won't be too dark in the kitchen and won't be too light either—so we can find a medium color grout that matches the tile and use 1/16" grout lines. I have used a super grout (can't remember name but it was about $40/bag) that is not epoxy, but has held very well in a place that is subject to the expansion/contraction cycle, was easy to use and should be resistant to stains. A grey grout can make stains less noticeable plus match the tile.
Finally back to the question—Formica wouldn't be so forgiving when I knock over a glass or drop a mug on it if it weren't a little bit soft, but is it too soft to tile over with thinset and porcelain? I know I could use 1/4" cement board, thinset on both sides (or maybe construction adhesive on the Formica, then cement board, then thinset and tile), but is it really necessary? I also know that the tendency is to recommend cement board if you don't really know (haven't tried tiling over the Formica), so I would prefer responses from people who have done it successfuly (or unsuccessfully).
Gene
Schluter has this type of project well covered. With todays variety of large format porcelain tiles, you can install over existing plastic laminate and get a nice stone look with minimal grout joints...and cost.
http://www.schluter.com/3147.aspx
I've never done anything like
I've never done anything like this, but if you have a drum of epoxy resin and activator in one of your sheds, I'd try that. On the other hand, maybe Deadnuts has the better idea.
Substrate.
Formica if it is newer is most likely done laminated to MDF. If it is older it is done over particle board. I would never use either of these as a substrate for tile even under backer board or a full float. It's not worth the risk.
follow up:
ended up tearing the entire counter top off, sink and all, and laying down a sheet of 1.5 cm baltic birch with 1/4" cement board over that. Granite tile on top of that. Has worked out well, son did the granite install.
wow, did not realize that was already 7-1/2 years ago!
Did try deep sanding a formica sample with 30 grit angle grinder and even cracking it with a hammer even, not a very good bond iirc. Also tried a vinyl acrylic primer, no good either compared to cement board base.
If it were my own house, would have used oak or hardmaple edges vs. cutting all those 2" wide edge pieces (used wet 10" diamond saw) One edge pied did debond about 5 years later, ok yet now.
Decoupling is the benefit
Coloradogene wrote:
I'm unsure why the Schluter product would be necessary over Formica since Formica is waterproof.
Gene
Ditra's primary purpose is not moisture proofing, although it does perform that function very well. You can achieve moisture proofing simply with Kerdi or similar material. The main benefit of using Ditra is to decouple the finish tile from the substrate. If you review the info on the Schluter website, you'll see that function well illustrated. Any movement due to dissimilar materials of the substrate and finish tile is "decoupled" within the Ditra shear plane. That is, the stress doesn't telegraph through.
Bear in mind that Ditra does not add a a structural component to the substrate. The substrate should be adequate for the application. I find that most countertops are well supported by cabinetry beneath and do not need to be additonally built up. If yours doesn't seem adequate, then you should do whatever it takes to make it so. That may mean bonding another layer of structural substrate to the laminate top before you install your Ditra.
When the decks were built on this house, they used Ditra over OSB then porcelain tile. One deck has had water damage underneath and some tiles are cracked. By keeping the deck free of snow (no one lived here for 2 years and snow built up and up) and drilling some drainage holes in the deck, I have stopped the water damage and don't see more cracks. This has not given me a lot of confidence in Ditra. Part (or all) of the problem is the OSB and perhaps Ditra is not supposed to be installed over it, especially outside. I know I wouldn't do it. The only good thing about the deck problem is that it got me several thousand dollars off the purchase price.
This experience made me associate Ditra with water damage and forget decoupling. Thanks for reminding me deadnuts.
Cabinets are pretty good quality—not as good as I'd like, but they provide good support. Countertops show no problems except for the ugly quotient.
I wouldn't entirely mind building up the countertops with Ditra and cement board since we are taller than the standard height for countertops makes comfortable, so another 1/2" might be a bit better. But this belt and suspenders approach may be too much.
So, as I mull over this (plenty of time, I have a great room to finish remodeling first), I am leaning in the Ditra direction. I hope I can get small amounts—about 24' x 24". I suppose it should be attached to backsplash and front lip adding about 6 or 7".
Gene
I have read DIYer books before that described placing tile over Formica. IIRC, they used mastic, not thinset -- the mastic would adhere far better to Formica, and for a countertop thinset is not really necessary.
But the jobs, close as I remember, used ceramic tile, not granite. The smaller ceramic, on mastic, would have little trouble with the dimensional stability of the Formica, and ceramic does not have the staining problem that granite does when used over mastic.
But isn't mastic not recommended for areas with water such as sinks?
What did the books say about roughing up the Formica? Sandpaper I assume, but what grit, or what other way of doing it? Did they recommended cement board or something like Ditra on top of Formica?
I'm not worried about staining with granite since we now think porcelain is a better tile for our purposes.
Gene
What I'm remembering was a long time ago, before Ditra, and probably in the early days of cement board.
And there's no real reason to avoid mastic in "wet areas". Mainly mastic is a poor choice under floor tile because it doesn't support the tile as well. Some/most variaties of mastic are more waterproof than thinset.
Actually, there is a big reason to avoid mastic in wet areas. Is called decomposition. Mastic is an organic based adhesive. Organics plus moisture at room temperature results in a high probability for mold and mildew propogation. . That's what organics are designed to do: breakdown when exposed to elements such as moisture.
Thinset, on the other hand, is a natural but inorganic material. It will not support the growth of micorganisms and is more appropriate for wet area tile installations.