We have a large portion of our house with ceramic flooring which is now looking very old fashioned. It has large grout lines (3/8 inch) which are white and almost impossible to keep clean. We do not want to have the entire floor taken up and replaced and were wondering if new modern porcelain with very minimal grout lines can be installed right over top of the existing ceramic floor successfully.
Although I would never do this myself, eHow has a step-by-step for this.
Keep in mind that doing this will add thickness to the floor, so transitions into other rooms might be tricky. According to This paper "an abrupt increase in height" of 1/4" (6mm) "is considered to be a threshold level for consideration of trip hazard for a pedestrian".
If this is done in a bathroom, the toilet flange (and/or other fixtures) will likely have to be raised to compensate for the new floor height.
Tile Over Tile Floors
1 Inspect the tile floor and make sure there are no loose tiles; the existing tile must be in good shape for re-tiling.
2 Clean the tile thoroughly to remove any wax or build-ups on the tile floor. Scuff or sand the tile to make the surface a little rough; this helps the new tile bond to the old tile. Rinse the floor after it has been sanded to remove any dusty particles.
3 Apply a floor leveler to the whole surface of the floor. If you have a raised area, begin there and work your way outwards in a circular motion. The floor leveler will fill in previous grout lines and make the floor level for the tile over tile application. Floor leveler is usually latex-based cement.
4 Use a screed to level the floor; a screed is usually a long and very straight board or level that will move the excess floor leveler to lower levels and will help you level the floor. Allow the floor leveler to cure according to directions, usually 24 hours.
5 Buy thin-set mortar that has a latex additive in it or replace the amount of water with a latex additive. Latex or epoxy type mortars are best for installing tile over tile. Mix and apply according to manufacturer's directions.
6 Set the new tile in small enough sections as the thin-set mortar directions call for. After the whole floor has been tiled, install the grout according to instructions. Seal the grout if directions call for it.
Tile Over Tile Walls
1 Clean the existing tile thoroughly to remove any wax or soap build-ups. Sand the cleaned tiles to rough up the surface for better adhesion. Rinse the sanded tiles to remove excess dust from sanding.
2 Use a latex or epoxy based thin-set mortar to set tiles into. Apply to the surface of the existing tiles according to manufacturer directions, setting the mortar base at a medium depth.
3 Install the tile a small section at a time, according to the thin-set directions. Apply grout and sealer according to directions.
While I have never done this on a floor, I have done this to a back splash wall in the kitchen. Granted what I did wasn't weight bearing, but it did hold when the cabinets over head suddenly broke their supports and rested solely on the 1/2 inch ledge on the back splash. So the mastic will hold, the only question then is the porcelain tiles themselves. If the ceramic is curved or bulges in the middle, you may crack the tiles you put over it, when you add weight to them. You can test this, if you can spare losing a tile, just place a porcelain tile over the ceramic and add lots of weight. If it holds, then I would go ahead and tile the entire floor.
- Clean the surface, make sure it is free of all dirt and any wax build up.
- Use self leveling compound, e.g. Ardex or TEC.
- Apply a liquid primer called "Grip" with a paint roller.
- Invest in a good setting material (superflex Thinset).
- Grout after 24-36 hrs.
- Seal the grout once it is cured within a week.
Although it's possible to do what you're asking I wouldn't recommend it. Especially if the current tile is laid on a wood floor. Although labor extensive you will be much better of and half a lot less potential for problems if you remove the old floor and start fresh. The prep work for laying over existing ceramic is tedious, in the end of believe you will save yourself a lot of work and trouble by removing the existing ceramic.
Flooring tiles over the existing tiles? Why not? It's a ceramic base. Simply make sure that is solid and sound.Loose ? Pull them up and fill the void with patching material. Stop questioning the existing floor.You are the one that have been living with that for years. When someone asks if he can install new tiles over the existing one, that assumes that floor is solid with some small problems or flaws.If this is not the case, than the right question should be - how do i remove the existing tiles from my floor. And this is the right moment to ask for advise, simply because there are no standards or fixed methods how to do it.Handymen out there have so many bright ideas.
Wash the existing flooring with bleach or the most aggressive cleaning solution that your wife knows best.Let the solution stay on the floor for a while. Do it again. Glossy tiles and bed knees.. ?? Rent the rotary floor sander and use the lowest grid number on the sand paper. Don't hope to see scratches on the ceramic tile... but it will create a very fine microscopic matte base for the primer that you have to use next after you have done the cleaning process again.