Designing Kitchens and Bathrooms - Metal lath vs backer board?

Hi - I'm in a funny situation (not so funny right now though). I am installing porcelain tile in my small foyer and attached bathroom. Previously the builder had put ceramic tile straight on OSB which I understand is bad.

I went to a 5 minute seminar at Home Depot and they recommended 1/4" inch hardiboard under the new tile, so I started down that route. Then while purchasing some saw blades that would cut hardiboard I met another Home Depot salesguy who said he lays tile for a living. He recommended using metal lath with a layer of thinset on it. He said it's cheaper and a big advantage is that it would be thinner and the height of my new tile would match the adjoining hardwood in the living room. So I changed directions and bought metal lath and spent all evening cutting and stapling down the metal lath.

Now I'm reading on the internet and several posters have said the metal lath method is bad, it won't last, and that no manufacturer supports that method.

So my question is should I rip up the lath and install hardiboard or is the metal lath just fine? I'd rather do it right now than have to redo it all later.

Thanks in advance!

Steve

Tear up the lath. Go with the cement board or if you want to keep down the height, use Ditra which is also available at HD.

Hardi must be installed on a bed of thinset and screwed down. Tape and thinset the joints as you set your tile.

The only thinsets to use come in a bag and you mix them yourself. Use nothing that comes premixed. Same for grout.

Shop there for your products. Stay away from the advice :wall:

Thanks for the quick reply. Saving height would be very nice because I would prefer the two surfaces be as close as possible to the same height.

How does Ditra compare to 1/4" hardiboard with respect to strength and thickness and ease of install?

If Ditra is thinner and just as strong I may go that route.

Cement board DOES NOT make your floor stronger. It provides a very suitable bonding surface for the thinset and tile.

Ditra does not make your floor stronger. It just provides a suitable bonding surface for your tile. But, it also isolates the tile from the horizontal seasonal expansion and contraction of the subflooring.

Tomorrow I walk into a customer's house with a 54 sf roll of Ditra. It weighs about 6 pounds. 3 sheets of cement board weigh about combined 120 lbs. Ditra cuts with scissors or a utility knife, cement board does not. Cement board gets set in thinset and screwed down, 58 screws per sheet. Ditra just gets embedded into thinset and rubbed down into place with a 2x4 or grout float. Cement board needs the seams spaced 1/8" apart and you fill the gap with thinset and go over it with a special mesh backer tape. Ditra just gets butted together and then you move on. Ditra will cost a bit more per sf than cbu, but once you add the tape, screws, and significantly longer time for working with it, Ditra beats cbu, hands down.



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Is Ditra thinner than hardi backer after installation? How much thinner?

BTW thanks for the advice. It's invaluable.

Ditra is 1/8" thick installed, cement board will be around 5/16 or so.

Then while purchasing some saw blades that would cut hardiboard I met another Home Depot salesguy who said he lays tile for a living. He recommended using metal lath with a layer of thinset on it. He said it's cheaper and a big advantage is that it would be thinner and the height of my new tile would match the adjoining hardwood in the living room. Steve

Amazing that there are hacks out there still doing these kind of installations. We all know why he wound up working at HD dont we.:rolleyes: :rolleyes: :rolleyes:

Here's the work progress so far:

step 1:
http://www.youtube.com/watch?v=_B4z59wsqyk

step 2:
http://www.youtube.com/watch?v=wwp0RqwdcAA

step 3:
http://www.youtube.com/watch?v=SnyApf8psAo

step 4:
http://www.youtube.com/watch?v=PRu-R7BSj8g

"We need an energy bill that encourages consumption" LOL

I'm glad you found it easy to work with. I guess it's set down now, hope you used a modified thinset, versabond, flexbond, etc, if you got your supplies at HD. In my parts, the only UNmodified they sell is Customblend. Not very good stuff. Head over to Lowes if you got one and get yourself a bag of Laticrete brand "Megabond" formerly known as "317" or Mapie's Kerabond or Keraset or hit up a tile store for some other brand of unmodified for your tile. $10-12 bag range will suffice. Flat trowel the ditra in all directions to ensure you fill the dovetails and then comb your lines. Keep those progress updates coming.


FYI, lath skimmed with thinset is not an old fashioned way, it's a hack way. Lath over tarpaper and then 1-1.25" of drypack is the indestructable old fashioned way.

Ditra has been around for over 20 years. Lath over the tar paper allowed the tile to ride over the subfloor. Ditra does the same thing in a much thinner and much lighter version.

I installed the Ditra last night and this morning. George Bush has a video of it:

Step 5:
http://www.youtube.com/watch?v=SCE5angtBX0

I'll prepare to lay the tile next. I'll figure out a pattern and lay it out. Do I cut all the tile for the edges before I lay the first tile or is there another way?

When you've established your layout, start going at it with your tile and thinset, and use a score and snap type cutter for straight cuts along the walls. You can wait to the next day to cut the more intricate cuts, like around the door jams on a wet saw or run out and do them real fast to set them as you do the rest of the field.

If you do choose to set the wet saw cuts the next day, be sure to fill the ditra waffles where those tiles will go as you set the rest and scrape down any trowel ridges or thinset purge from the adjacent tiles before moving on.

The next day, after making those fancy cuts, you can back butter them using a rapid setting mortar (in this case, modified is ok), and be grouting the whole floor about 2 hours later.

I'd pay no attention to the size of the tile along the wall behind the toilet and vanity. It's so blocked from view with that layout. You have enough other walls and other stuff to worry about in there.

I appreciate seeing the honest side of George. Thanks for the updates. Dick shot the duck?

I think that you should rip up the lath and install hardiboard. Believe me metal lath is a bad idea.

Ok, it's been a while and I have finally returned to the tile job. Here's the video for step 6:
I said George is convincing the company to nuke Iran but I meant to say country. Perhaps I committed a George Bushism myself.
http://www.youtube.com/watch?v=IthSWXUyeTk

Here's step 7:
http://www.youtube.com/watch?v=2d8eIYOub4s

And here's where I am now, step 8. I have a question. How do I make the joint between the tile and the hardwood? I don't want to put a big klunky strip of trim over the seam. I want the transition to be smooth so nobody stumps their toes on it or trips on it. It seems more elegant that way. I have seen schluter, the metal strips that go between the tile and hardwood. If I use that must I put an expansion crack between the schluter and the hardwood?

Are there other ways to build the joint so it survives expansion and is flat on top?

Here's the video:
http://www.youtube.com/watch?v=MtQ0yQ0Vm14

Thanks for any help.