Getting the rock for my hearth tomorrow... Need a little advice

[Firenutz]

I'm building a corner hearth for my pellet stove. I have 1-1/2" of plywood, 1/2" of micore and I'm getting 1" thick pennsylvania bluestone which has been cut into tile like shapes that I pre-measured. I'm thinking of using concrete to set the stones but I'm unsure of what to grout the cracks with. Would it be possible to grout the cracks with concrete? Should I go with a regular grout? I've planned for 1/4" grout lines. This is my first attempt at a project like this so any crticism/guidance is welcome. So far this thing is built like a sherman tank. the outside border is 3-1/4" tall baseboard that I mitred,stained, and secured to the plywood forming a tray of sorts. I have 1-3/8" to go up above the micore to be level with the baseboard trim. I can get some pics up maybe tomorrow of what's going on.

 

[begreen]

Will there be a backerboard for the stone like Wonderboard or Durock? I would think that mortar would work between stones but I am no mason. You might want to ask the experts here:

http://johnbridge.com/vbulletin/index.php

 

[ktfinch2000]

I would use sanded grout. This type of grout comes in many colors, has some flex to it and can do a joint up to a half inch. I used this for my hearth and I have 1/4" grout lines also. I also think you might want to go with a tile mortar instead of concrete also because the mortar also has some flex. They have quick set and regular depending how long you want to wait before grouting. Also if you are going against wood trim or are wrapping the hearth in wood they sell a grout caulk that you can use to grout against the wood so it does not crack and it matches the grout perfectly. Check Lowes or depot they have a good selection. Good luck!

 

[Firenutz]

Very nice hearth! Mine is the same shape but the tiles will be larger and laid out different. What would crack if I didn't use the grout caulk, the wood or the grout? The mortar will be spread directly on the micore which I think is just overpriced durock. I'll look into using some mortar. Thanks for the advice!

 

[ktfinch2000]

wood expands and contracts so you will notice a hair line crack around the outside edge where the grout meets the wood over time. If you use the caulk it will move with the wood and not crack. good luck

 

[nailed_nailer]

I built my hearth pad out of 3/4" ply under 1/2" Durock under brick pavers mortared to the Durock. For the grout I used polymeric sand.
It is the sand they used for outside paver walkways. The beauty of it is that you install the sand dry.

Pour it into the joints, sweep it around, vibrate it with a pad sander. Once you get looking how you like it.
You mist it 2 or three times to activate the adhesive (cement) in the sand.

It dries hard.

A year later it still looks great. I regularly vacuum up the inevitable soot you get when cleaning the stove. So far none of the sand has lifted out.

I tried to attach a photo but photobucket seems to be having a problem tonight.

---Nailer---

 

[Firenutz]

I built my hearth pad out of 3/4" ply under 1/2" Durock under brick pavers mortared to the Durock. For the grout I used polymeric sand.
It is the sand they used for outside paver walkways. The beauty of it is that you install the sand dry.

Pour it into the joints, sweep it around, vibrate it with a pad sander. Once you get looking how you like it.
You mist it 2 or three times to activate the adhesive (cement) in the sand.

It dries hard.

A year later it still looks great. I regularly vacuum up the inevitable soot you get when cleaning the stove. So far none of the sand has lifted out.

I tried to attach a photo but photobucket seems to be having a problem tonight.

---Nailer---

I saw them do a brick patio on a home improvement show using that stuff. It worked pretty good. I'll definately look into that. Less chance for me to screw it up!