# How big of a gap in hardie board can I fill with thinset?



## onlinehandyman (Aug 21, 2008)

I have done thinset in very small places like that and it has worked just fine. I have even done grout like that where it's too small to cut a tile and it worked just fine. You would think that it would crack, but it doesn't. Good Luck!


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## onlinehandyman (Aug 21, 2008)

I have done thinset in very small places like that and it has worked just fine. I have even done grout like that where it's too small to cut a tile and it worked just fine. You would think that it would crack, but it doesn't. Good Luck!


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## Constant Improvement (Oct 30, 2008)

Thanks for the reply... thats what I was hoping

my drill battery dies last night, and I only got one sheet of hardie board down, but tonight I plan on finishing it. 

After re-reading my original post I thought I would clarify one thing: the gap is around 1" to 1.5" wide but it the entire length of the door frame (28"), so about 30-40 square inched total... dont know if it makes a difference.

Thanks,
Eric


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## angus242 (May 1, 2008)

I disagree. Just spend the time to put a piece of CBU in the gap. Thinset likes to shrink when it cures. I'm not comfortable with anything over 1/2" thick. 
If you attempt this, 2 things might happen:
1. The thinset will shrink and you'll lose bond to the tile
2. The thinset will remain bonded to the tile but pull the tile with it and SNAP

For a gap that large, just add the CBU.


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## Constant Improvement (Oct 30, 2008)

angus242 said:


> I disagree. Just spend the time to put a piece of CBU in the gap. Thinset likes to shrink when it cures. I'm not comfortable with anything over 1/2" thick.
> If you attempt this, 2 things might happen:
> 1. The thinset will shrink and you'll lose bond to the tile
> 2. The thinset will remain bonded to the tile but pull the tile with it and SNAP
> ...


OK... I'm glad I asked the question then. If there is any concern at all, I might as well just do it then (not like its that hard). I just wasent sure whether having a sliver of hardie board that thin, or an area of thinset that thick, would be worse... 

Thanks


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## Termite (Apr 13, 2008)

I'm with Angus 100% on this. You should cut a narrow strip of backerboard and set the backerboard strip in thinset as required, then screw or nail it down.


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## Constant Improvement (Oct 30, 2008)

thekctermite said:


> I'm with Angus 100% on this. You should cut a narrow strip of backerboard and set the backerboard strip in thinset as required, then screw or nail it down.


check... thanks guys.


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## homedude (Mar 21, 2011)

This is why I love mud set


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