Mud Floor Questions Please?

[brianosaur]

I have a concrete slab a over the entire ground floor of my home. In several rooms I installed 3/4" wood floors on 3/4" plywood glued & nailed into the slab. These floors are now 1 1/2" higher then the base slab.
I now wish to install a tile floor in my kitchen which has adjacent doorways to the wood flooring. I want the tile level to the hardwood.
My plan was to put a mud floor onto the existing slab to elevate the tiles to the height i desire, but I figured I'd ask a few questions first. (4 please) :think:

Do I need felt on the slab before the mud or is that just to prevent moisture from going into a wood subfloor?

I was going to nail down wire lathe to the slab, using powder actuated masonary nails with washers-before floating the mud. Is this necessary for stength?

How thick should the mud be? I assume tiles are about 1/4" thick so a 1 1/4" mud base should be o.k. Do I need to allow about 1/8" for thin set? ....making the mud 1 1/8"? Remember I'm trying to get to 1 1/2" total.

Finally, should I use portland and sand for the mud? I read 1:4 is the correct proportion as long as it's pretty dry.

Thanks for your time :nod:

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[bbcamp]

Brian, I'm no pro, but I believe that you are at that thickness that you could either float your floor or bond it to the existing concrete. Bonding (I think) would be better, especially if the existing slab didn't have any cracks in it, and wasn't coated with any bond breaking coating or something like that. Otherwise, floating would be the right thing. Hopefully, one of the mud men will clear this up for you, I'm just bumping you to the top. :D

[Unregistered]

Bonding (I think) would be better, especially if the existing slab didn't have any cracks in it, and wasn't coated with any bond breaking coating or something like that. :D

There are old, nasty, ridgid tiles from the 70's on the slab now with some type of adhesive. I think its called "vynal abestos" or something. They aren't masonary type tiles but they're not soft like lanolium either.

Anyway, when I pulled a few up there was a black mastic residue left on the slab. Not thick at all, but it was still present. That's why I was thinking about the lathe and mud.

[Davy]

I wouldn't use lath or felt, I would bond it to the slab with a good thinset, something like Versabond. Start the mud height at the wood floor, holding it down the thickness of your tile plus about 1/8 for thinset. Do a search on "trick stick", it would be handy to use along the wood. :)

[brianosaur]

I posted another thread on raising up a mud floor on top of a slab, but I'm hoping to receive an answer to a question that was raised in that thread.

The slab is 35 years old and there are old, nasty, ridgid tiles (not ceramic) from the 70's on the slab now with some type of adhesive or mastic adhering them.

I pulled a few up a few tiles and there was a black adhesive/mastic residue left on the slab. It was not thick at all, but it was still present.

In my other thread I didn't mention the residue originally.

I was told to apply 1/8" thin set to the slab before laying down the 1 1/4" mud so as the two will bond.

Will this create a problem of bonding the mud to the slab with the thinset?

The oher thread was http://www.johnbridge.com/vbulletin/showthread.php?p=205354#post205354

[cx]

I merged you with your original thread, Brian. Just keep all your questions on this thread until the project is completed. Whenever you or someone else makes a post to the thread, it will move itself to the top of the queue.

Now we just need somebody to answer your question. :)

[Rd Tile]

That black adhesive is cutback adhesive, don't try sanding this up, it probably contains asbestos, as well as those 9" tile you already removed, use a good modified thinset rated for cutback adhesive, Flexbond should work fine for this, mix it a little wet like a paste and paint it on the floor with a masons brush, then put your mud over it while it's still wet.:)

Yes, 4 parts mason sand to one part portland cement is fine.:)