Concrete under insert?

[Toomb]

Guys,


I have a heatilator woodburning fireplace that I put a Rockland 550 insert in last year. The original fireplace had firebrick on the floor of the fireplace and a brick hearth. The fireplace is in a room on slab. The original hearth is flush with the floor........which actually puts it below the level of the finished floor. We Want to raise the hearth up a bit and are using a 1.5-2 inch slab of limestone. My question is what to do in the firebox where the insert will sit. I was originally goind to use firebrick, but am contemplating just pouring concrete in over top of the original firebrick. What do you think? My thinking is it isn't going to be seen. I don't need more insulation.......thanks . Chris

 

[Simonkenton]

How thick would the concrete be?

 

[Toomb]

About 2.5 inches......was gonna use high strength concrete. Or is there any other product i could use ?

 

[kennyp2339]

why not just get 2 more 8" wide pieces of limestone and put them in the fireplace then re-install the insert? Pouring concrete seems like a lot of work and if you ever want to remove the insert and use the fire place you just got to pop out the additional limestone pieces.

 

[Toomb]

I could do that, but i will never burn a fire in the fireplace. I may replace the insert with a stove at some point. Pouring concrete in that small space is nothing compared to what I have done at this point. In fact, a pourable product would be easier than mortar and cutting firebricks. I just don't know enough about available concrete products, and weather concrete can withstand the heat under the insert or a free standing stove?............

 

[Toomb]

What I am talking about......

 

[Easy Livin’ 3000]

Poured concrete would be fine under an insert in your application, I think.

I wouldn't do that. I'd just use loose bricks, stacked cement board, whatever masonry product that gets you to your desired thickness. Doesn't have to fill the entire space, so if you found bricks the right thickness, just dry fit them, probably little or no cutting required. If you really wanted to make a mess, and the bricks leave too much gap around the perimeter, fill the perimeter gap with mortar. You could mix that much in a bucket.

Hopefully someone who actually knows what they are talking about will chime in.

 

[Sodbuster]

Couple pieces of steel channel would work just fine too.

 

[Simonkenton]

I think poured concrete would work fine. I mean, my hearth is made of big flat rocks set in mortar. The mortar takes that heat just fine. Really not that much heat goes down from a wood stove.