Hearth help!

[sj6x]

I'm getting a new insert and I have 2 questions.

#1 My fireplace is natural stone built in 1935. It will never be used as a fireplace again. I need to do some repairs inside of it, as it has a bunch of holes and cracks between the natural stones. Can I patch it up with regular mortar, rather than refractory cement since it will never be used as a fireplace again, only with a wood insert?

#2. Currently the firebox and hearth sits at floor level. I want to raise it 4" off the ground. I will build a frame using 2x4's and pour mortar into that to get the 4" height. I have a lot of cement boards in the basement, and wondering if I can cut those and stack them about 3 inches, and then pour the mortar over it all? I don't have a cement mixer and I don't like the idea of mixing all that mortar by hand. Also I'm a little worried about the weight of all that cement on my floor, although it looks like in the crawlspace under the house that there's a big cement pillar right under the fireplace.

 

[Shrewboy]

Hi sj!
What model is the insert that you are putting in? We will need to know that in order to see what the clearances need to be

 

[kennyp2339]

To patch the cracks use furnace cement, as far as raising the stove 4" get some boiler block and put the under the insert.

 

[sj6x]

Hi sj!
What model is the insert that you are putting in? We will need to know that in order to see what the clearances need to be

It's a stuv 16-68 wood burning insert. It will go right up against the inside of the fireplace as it's about the same width and depth as my fireplace opening. Keep in mind that my fireplace is lined with big stone, so this would be to point the cracks in between the stones.

 

[sj6x]

To patch the cracks use furnace cement, as far as raising the stove 4" get some boiler block and put the under the insert.

Thank you, I'm reading that furnace cement need 500 degree to cure... not sure my wood burning stove insert will reach that temperature on the outside? I guess it will?