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hardibacker - how soon can you lay tile?

hurnik's picture

I looked at the hardibacker website and and instructions and it doesn't state how soon you can lay tile after you install the hardibacker.

Since it requires a mortar underneath the backerboard, do you have to wait 24-48 hours for it to cure before you can start laying tile on top of the hardibacker?

(post #106820, reply #1 of 11)

A year ago, I put travertine down immediatly after in a bathroom. No issues so far but 1 job is a pretty small sample size to go by.

(post #106820, reply #2 of 11)

Immediately if you are not doing jumping jacks.

You don't use mortar under the hardieboard.
You use thinset and screws.
or adhesive and screws.
If you are using a mortarbed, you don't need hardi.

But it takes time to do layout lines and make preliminary cuts anyways so by time that is done after installing all the hardi, day is done and time to go home anyways. so all I have done is one day after hardi installation.

 

 


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(post #106820, reply #3 of 11)

Um, this is what they're website said:

Dry-set mortar for use between subfloor and cement board only (complying with ANSI A118.1).

(post #106820, reply #4 of 11)

Got a link?
I'm trying to figure out what they are calling "dry set" mortar. Never heard that one.
Never mind same thing as thinset
"The terms thinset cement, thinset mortar, dryset mortar and drybond mortar are synonymous. "
from
http://www.tileusa.com/thinset-mortar_faq.htm

so you are using thinset, not a mortar bed base.

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Edited 8/9/2008 12:56 pm ET by Piffin

 

 

Oh Well,

We did the best we could...

(post #106820, reply #5 of 11)

Is this the link??

Dry set (ANSI 118.1) or acrylic modified thinset (ANSI 118.4) is specified between the HardieBacker board and the subfloor to eliminate any deviations between our product and the subfloor. This decreases the probability of popping or cracking tiles due to deflection and air pockets.

http://www.jameshardie.com/homeowner/helpSupport_FAQs.shtml#28

(post #106820, reply #7 of 11)

Dry set mortar is simplely thinset.

It is called dry set because it is used to set tile on a DRY substrate.

That is verse a wet set installation where tile is directly placed on a wet mortar bed.

Standard installation for hardy backer is a bed of thinset frp, 1/4" square notch trowel.

The purpose is to fill in any irregularities between the hardy and the subfloor so that the hardy is supported 100%. It is not used as an adhesvie. Screws or nails are used to hold it in place.

I can't lay my hands my TCA handbook, but I believe that they call out the thinset bed for use under all forms of concrete and fiber backer boards.

.
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(post #106820, reply #8 of 11)

Yeah, I knew all the rest, just never heard the term dryset before. But I have done a lot of hardie on thinset or adhesive

 

 


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Taunton University of
Knowledge FHB Campus at Breaktime.
 where ...
Excellence is its own reward!

 

 

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We did the best we could...

(post #106820, reply #9 of 11)

Thanks. I didn't know that "thinset" and mortar were one and the same (at least for this purpose).

Although reading further it looks like after installing the hardibacker, I have to put the adhesive tape on, thinset over that and wait 24 hours before installing the tile.

I may go with the Ditra instead then (no waiting).

My main issue is that I've got 3/4" plank subfloor, so I'll have to put another 1/2" plywood/OSB down before the Ditra (so I figured may as well go with the hardibacker). But I'd prefer to not have to lose one day just waiting for the underlayment to be prepped before I can lay the tile (then it's another 24 hours minimum before grouting).

(post #106820, reply #10 of 11)

Some place, might have been Brynes book, that for a floor you don't need to preinstall the tape and thinset to bond it.

Put it down when you put donw the tile. Less of a change of getting a buildup and lump.

Need to be careful with troweling it out to keep from catching and tearing out the tape.

.
.
A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.
. William the Geezer, the sequel to Billy the Kid - Shoe

(post #106820, reply #11 of 11)

thinset and mortar are not the same thing for this purpose or any other.

Thinset mortar and dryset mortar are the same thing. They have additives to make them workable and to set up faster and/or to have more stickiness. They use a finer agregate

but when you just say mortar, it is portland and fine aggregate, probably with masonry lime and is used in minimum thicknesses of 3/8". In tile work, it would be more like a 1-1/2" mortar bed. That is the old way of doing tile and can be done in one day for a small enough area with enough skill and experience.

I am not just going into this to be picky.

It is because now that you mention Ditra, it is important for you to understand all these differences.
In the genre of thinset, there is modified and unmodified thinset. Sometimes they are interchangeable in use and sometimes not.
unmodified is a setting type material like mortar and concrete and grout.
Modified has altex modifiers added that changes the way it works. The modifiers makes it more tolerant of movement and freezing, etc. There are another step up in stickiness also to adhere to some surfaces and they retain moisture in the mix for when the surface used is porous in such a degree that it can suck water out of the mix before it cures. But they require that they dry also instead of just curing.

When you use Ditra, read the instructions carefully. The type of thinset used with it varies according to the substrate you are going over. as I recal, you want modified between ditra and a wood underlayment, and unmod over the hardie or between tile and the Ditra.

So you may need modified under your Ditra and unmodified over it.

 

 


Welcome to the
Taunton University of
Knowledge FHB Campus at Breaktime.
 where ...
Excellence is its own reward!

 

 

Oh Well,

We did the best we could...

(post #106820, reply #6 of 11)

Piffin has brought ya up to speed...

 


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