want to tile counter top with out using hardboard
It can, but it won't hold up very well. The formica will break up underneath, leaving an uneven tile surface and you having to regrout it often. Take up the formica. - Stuart
I have done it and it was over 7 years ago and no problems at all. I even stand on the counter sometimes. First you will need to sand the formica with a coarse sandpaper followed by 2 coats of oil-based Kilz-It. When that it dry you are ready to thinset and lay your tiles.
It can and will hold up on one condition w/o a backer board.The top must be 2 3/4 ply wood or nova ply( HDF) , not the single layer counter top with the false edge that makes it look like its 1 1/2 thick. Other wise you need a backer board so the tile meets tile codes( ATC and TCA guide lines) for a minimum substrate which is 1 1/4 A few special thing need to be done but it will work. Any questions you can e mail me thru my avatar and check my qualifications GL
Can yes you can (can means able to). And you may do it as long as the subsurface of the counter where you place the tile on is solid and will not move (most counter tops have too much movement in them to keep the grout from cracking). You can check this by standing or sitting on the counter top and see if your weight makes even the slightest bow in the counter top. If you decide your counter top is strong and stable enough then make sure you sand (rough up) the Formica before you try to cover it with anything else. What you might consider doing is placing either 1/2 inch cement board or another layer of 3/4 birch plywood or MDF board screwed and glued down to the existing counter top. Tile is expensive so do it right.
