Lath vs backer board

I would like to use metal lath for the height, but is there an advantage or disadvantage to using lath or backer board? I have a bathroom with tongue and groove and was told that I could not put backer directly onto this. Can I put metal lath directly over the T&G and 16"o.c. joists.

 

No way, no how. As in all previous posts, you cannot go over dimensional lumber subfloors without at the very least, a layer of 1/2" bcx ply, then backer. The hard part was your kitchen subfloor. The bath subfloor should be easy to replace. If there was an alternative for going over the plank subfloor, we'd have offered it. As a matter of fact, the only time lath should be under a tile floor is if you pack 1 1/4" of drypack over lath over roofing felt. Lath can't ever be used to reinforce thinset. Those that do it or endorse it, don't know what they are doing, PERIOD! At this point you are also aware that luan is NEVER an option as a tile underlayment. I will guard against bad advice you may recieve contradicting what I've stated. By the way, I hope you find this info useful to your thread...the lath and thinset scratch coat method of which you were aware of or was suggested to you has failed EVERY industry test and is not an approved method for setting tile by any trade organization or thinset manufacturer.

 

Thanks TB
I did understand not to use luan when applying ceramic tile. When is lath used for tile?

 

Lath is only used in the following instances. For reinforcement of Self leveling cements poured over exterior grade plywood at a minimum depth of 3/8". The plywood and the supporting structure must meet a minimum deflection, which must be L/360 for ceramic or other floors or L/720 for stone. Lath is also used when installing a mud shower pan to wrap the shower curb or in the preslope bed of mud under the shower pan liner. it's also used when mudding floors (which can be done over plank subfloor, but must be 1 1/4" thick), coutertops and walls prior to tile installation. Notice how none of the uses are with thinset?

 

The point here being...Lath has no strength by itself. It has to be supported underneath and on top. Just skimming it with thin set is basically a waste of time and material.

So, as already mentioned...tie all those individual boards together with a layer of plywood before you do anything. Then you will have a decent subfloor to work with and you can think about what you want to use next, such as cement board or Ditra, before you tile.