# How to grout a slate floor under a wood stove?



## georgepds (Dec 11, 2012)

Not sure I’m in the right place for this question. I have a  Jotul combi fire #4 ( the one that looks like an Easter island head) . It sits on a grouted slate floor

After years of use the grout has dried and the slates have come loose. My best guess is I used the wrong grout when I laid the tile some 20 years ago

I need a recommendation as to how to best lay the slate so it does not come loose


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## ScotO (Dec 11, 2012)

First, make sure the substrate (the surface UNDER the tile) isn't to blame for the grout failing.  If you are going to re-do the slate tile, it'd probably be good insurance to put some cement board (Durock NextGen or Hardibacker) down for a new, clean, and ready-to-go surface for your tile......Use good thinset and good grout, and it'll be a cakewalk.......


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## Tramontana (Dec 12, 2012)

On the plus side, it worked for 20 years, but a slate floor should have held up longer, and I would suspect a material failure somewhere.

If you are going to replace/reset the entire floor I agree with Scotty, clean everything really well, install a good cementitious backer board and use quality thin set and grout.  These are not products to skimp with IMHO.

Cheers!


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## stee6043 (Dec 12, 2012)

Scotty Overkill said:


> First, make sure the substrate (the surface UNDER the tile) isn't to blame for the grout failing. If you are going to re-do the slate tile, it'd probably be good insurance to put some cement board (Durock NextGen or Hardibacker) down for a new, clean, and ready-to-go surface for your tile......Use good thinset and good grout, and it'll be a cakewalk.......


 
Anyone that says tile is a cakewalk is either a professional or is just plain crazy!  ha.


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## Eatonpcat (Dec 12, 2012)

stee6043 said:


> Anyone that says tile is a cakewalk is either a professional or is just plain crazy! ha.


 
Tile is very easy in my opinion!


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## georgepds (Dec 12, 2012)

Thank you both


I'm going to replace the Jotul with a progress hybrid.. which calls for a subfloor with an r ~0.8. With an "ash lip" (do they mean ash pan?) this goes down to 0.4.

1/2" Cement board,  R=0.39, and tile, R=0.02, meets this lower spec

One thing I'm thinking about is mineral board under the tile.I found one product below, it has an R=1.04.. My tile area is roughly 4x6 so I'd need several sheets ( they come 2x4). The advantage would be to exceed the R spec

Anyone have any experience with mineral board? Anyone know another vendor?

TIA

--G


SBI Micore-300 Mineral Fiber Board -

http://www.efireplacestore.com/sbi-...nnelid=FROOG&gclid=CK3yo-PUk7QCFS-RPAodDgcAGA


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## georgepds (Dec 12, 2012)

georgepds said:


> Thank you both
> 
> 
> I'm going to replace the Jotul with a progress hybrid.. which calls for a subfloor with an r ~0.8. With an "ash lip" (do they mean ash pan?) this goes down to 0.4.
> ...


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## georgepds (Dec 12, 2012)

Opps.. they do not mean ash pan

They mean a small plate that extends out in front of the stove

http://woodstocksoapstoneco.blogspot.com/2011/11/progress-hybrid-with-front-ash-lip.html


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## firefighterjake (Dec 12, 2012)

stee6043 said:


> Anyone that says tile is a cakewalk is either a professional or is just plain crazy! ha.


 

Not a professional . . . or plain crazy . . . just very methodical and I listened to what folks here were saying about how to build a hearth and tile . . .


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## ScotO (Dec 12, 2012)

stee6043 said:


> Anyone that says tile is a cakewalk is either a professional or is just plain crazy!  ha.


tile is a Cakewalk.....

Now hanging stone veneer is a tad harder....this is what I'm into right now....

No I am NOT a professional.   Yes I AM crazy......


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## fishingpol (Dec 12, 2012)

Good advice already, they gave you a good start.  20 years did well for you.   I did a slate for my hearth rebuild.  I removed the old wood that had split and dried out resulting in cracking mortar and loose tiles.  If putting in a PH, make sure you have plenty of strength in the floor below it to reduce deflection which would cause popped tiles.  I rebuilt using metal joist hangers, new 2 x's toenailed in.  Construction adhesive on top of the 2 x's, 3/4" plywood screwed and glued down, then hardi and concrete to bring it to level. There will be a lot of weight sitting on that hearth.  Good luck.  Be sure to put up some before and after photos.


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