Flooring Tile - Plastic Mesh Under Tile Floor

I am installing a ceramic tile floor in my bathroom. I didn't want to use backer board because that would make my bathroom a 1/2 inch taller than my hallway. My mother recently had installers put porcelain tile in her kitchen and they used a mesh under the tile. I thought that would solve my height problem.

I went to my local Daltile dealer and bought mesh and then asked my mother how her installers cut and installed the metal mesh. She told me her mesh wasn't metal, but plastic which they cut with scissors and stapled down.

Now my question is can the metal mesh be used the same as the plastic or is that just a very bad idea?

I appreciate any comments and ideas about this.

Thank You.

I think what your mom's installers used was a product called Ditra, by Schluter.

I'm not sure if staples are used in the installation, but it is installed with thinset onto a subfloor and then the tiles are mortared on top of that. I do not know what Daltile carries, but most large tile shops should carry Ditra. I think most Home Depots will order it for you.

I do not think the metal mesh will work for you.

There's an old hack method of stapling metal lath and coating it with thinset. This method come up for reveiw periodicly for inclusion as a method in the TCNA handbook but never made it due to never being able to pass industry testing. Recently introduced but not included in the TCNA handbook Mapei's mapelath system. The only thin installation using a plastic mesh that is covered by a mfg warranty and is an update of the above listed method commonly refered to as a "Jersey Mud Job" Their proprietary method is very specific about the materials to use. Given the expense is much more than using a cbu, I doubt the proper materials were used and more often plastic lath is being used for a Jersey mud job as a moment of carelessness with metal lath will shred your skin.

Plastic lath is made by a few manufacturers for self levelling cement reinforcement over plywood as a setting method but requires minimum depths of pours from 3/8" to 1/2" and slc is very evpensive.

1/4" cbu is all you need for floors and there are membranes available for tile installations that outperform cbus that are significantly thinner as well. Noble CIS is only 1/16" installed and Schluter Ditra is only 1/8" thick installed.

Any method is only as good as the floor below. What's your subfloor, any layer on it and joist size, spacing and unsupported span?

I'd ask your mother what if anything was removed from her floor prior to the installation. Many shortcuts will outlast the labor warranty but certain factors become a "when" not an "if" that issues will develop later. In some states, the labor warranty period does not begin until a proper installation is completed, even if it's a few years down the road, unless every mfg requirement is followed, it's not a proper installation.