Typical kitchen floor, but only 1/2" plywood subfloor instead of5/8". The subfloor is kind of springy, I think. I suppose the bestway would be to pull up everything and replace it with 3/4" tongueand groove, but I'd have to remove cabinets, etc. So what I planon is adding 1/4" plywood for a bit of strength to the existing 1/2",using staples and glue (liquid nails), and then adding 1/2 hardibacker. The height then matches the old floor and I thinkit'd be pretty strong for ceramic tile.Sound good?Another thing is that the hardibacker half-inch stuff is labeledfor "walls", but was sold to me as being for floors. I'm told it'sthe same stuff. And the website for Hardie says the hardibacker500 is primarily used for walls, while the quarter-inch stuff isfor floors.Why? Am I making a mistake, or will I just have a level, strongerfloor? (thinset mortar on top of the half-inch HB, for 12x12ceramic tiles)Still sound good?TIA!Mark

1/2 Hardibacker Floor?

Nov 17, 2003 22 Replies

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G. Mark Stewart 22 years ago

Well, thanks for all the input folks. I've got a pretty good idea on how to proceed.

Mark

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G. Mark Stewart 22 years ago

I'm a little lost here -- what else could it be? Surely no one uses the backer board without a decent sub-floor under it, right? Like I said, if there's some detail you need that I've left out, I'll do my best.

All I have is a first impression that he, as well, should seek out the help of a pro.

But tantrums aside, I'm curious about a couple things. Firstly, I didn't see anything on the Hardie website to indicate that 1/2 was weaker than

1/4. In fact, the brochure in the store stated that 1/2 was dimensioned to replace 1/2 sheetrock, and 1/4 was dimensioned to minimize the rise of the floor surface, no other indications.

Secondly, it seems to me that adding the 1/4" to 1/2" and gluing is less strong than a single 3/4" layer. But that this is assuming that the glue used is weaker (more sparsely applied) than the bond between layers of plywood. Am I right or wrong, here?

TIA!

Mark

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Randy Calhoun 22 years ago

Go back to their site and look at specs. Strengths are given there.

What's the dif? Adding the 1/4" to 1/2" still produces an inferior substrate for ceramic.

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