Installing a tile fireplace hearth

mlheath

We tore out a "main level" raised hearth that had been poured onto a concrete slab foundation so we could lower the hearth to floor level. The surface of the slab is mostly level but has a few small imperfections. My contractor suggested a cement board, Home Depot recommended a flexible liner in a roll to use as a liner between our new ceramic tiles and the original slab. The carpet surrounding the hearth will butt up to the tiles for now until we tile the whole floor someday, if ever.

I want to make certain everything is level (now and for possible future tie-in), no movement, minimal risk of tile and grout crack, and whatever has proper moisture (and heat?) barrier that might be needed.


The finished height is not an issue because the contractor will cut the tiles to fit around the base of our mantle, but there may be a slight "level from one side to the other" issue. I've read NOT to use (Hardi) cement board (they never said why not) on a slab somewhere, and somewhere else read that it's OK.


So what would you guys recommend and why: The flexible stuff, cement board, or nothing at all and just adhere the tile to the slab with thin-set?


Thanks,
Merrill

joecaption

Since we have no picture, no mention of just how far it's out of level or what condition the slab is now in, going to be hard to come up with some suggestions.
I would never use tile board in direct contact with the slab, and I have no clue where they came up with the idea of a rubber membraine.
Tile directly on top of a slab is done all the time.

ddawg16

What Joe said......

On a related note....you have to use caution when taking advice from the big box stores....especially during the daytime. At night, you can get some good experienced guys working part time....but during the day.....especially full time guys....well.....there is a reason they are working at HD or Lowes......

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mlheath

Thanks, guys. The floor is level, just a few rough spots. All-in-all I'd say it's in good shape. The lining HD suggested was recommended by the manufacturer. It was like a flexible mesh of some kind.

It sounds like just using thinset and putting the tile directly on the slab is the way to go.

Thanks.

joecaption

Was it orange by chance?
That would be fine if you were trying to water proof it, or there was an expantion crack there.
You have to grind or chisle off any high spots, the low spoats of flaws can be leveld off with thin set or nongypsom floor leveler.

Canarywood1

"Home Depot recommended a flexible liner in a roll to use as a liner between our new ceramic tiles and the original slab"



Maybe they recommended Ditra.

joecaption

That's what I was thinking, but see no reason for it in this case.

jomama45

The biggest question would be this: How is the hearth extension constructed? Is it a structural cantilevered slab of concrete, or is it simply part of the first floor? Is there a basement/crawlspace below, or is it a slab on grade house?