Monolithic Hearth Slab

Hi getting ready to to form up for a single slab poor of the hearth deck. I know I need to have the knock out to accommodate the insulating layer of vermiculite and cement. I don’t really want brick around the perimeter of the firebrick cooking hearth. I was planning on pouring the hearth slab thick enough to accommodate the firebrick as well. Do you foresee any issue with this.
Dave LaCroix
Branford, CT 06405

Shouldn’t be a problem. I have a friend who (almost) did it that way. He did a monolithic slab (with a curved front) but allowed enough space to put a 3/4" piece of granite on top flush with the firebrick. He found a remnant at a local shop that he got cheap and it looks great.

Thanks, I wasn’t sure if there would be an issue cracking in the corners.

Hi Dave,

I don’t think there will. The rebar matrix is still essential, and pay careful attention to your concrete mix.

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I am planning on a mono pour of the deck as well. Same as yourself I do not want the brick deck, instead planning a natural rock exterior from ground up. Did you have any issues with the width of the oven building fitting on that foot print? If so what were they. Also how thick did you pour the deck. On the instructions it shows the combined thickness at 9.5 inches. Is that what you poured? Can it be a couple inches less?

My project is merging the Mattone Barile with a DIY fireplace design from Backyard Flare.

Central Wisconsin

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Hey Joe, very cool looking project. I did not have an issue as I cantilevered out over the block using the high strength 5000 mix. I may have over built the rebar matrix but didn’t want to take any chances. I set 5’ long rebar through the block and then tied the hearth deck rebar into it and cut to length so the mono pour with its rebar matrix is tied right back to the slab. I left a large overhang because I am using an oversized antique brick for the outside skin of both base and oven shell. I hope this makes sense see picks below.

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Dave thanks for the insight on your pour. I like the rebar configuration. How thick is your finished slab?
In my 5th course I built an arch to go with the fireplace design. The weekend of the 20th I will make some adjustments to my form. I guess it should be 9.5 inches thick to hold the vermiculite layer, sand layer and brick.
My plan is to stay flush with the cement block on the back and two sides. My property has an abundance of white quartzite ranging in size from those that fit in my palm to boulders needing a backhoe to move. I plan to do the exterior of the entire project with this quartz. That said the quartzite will bring out the exterior walls another 6 inches minimum. The cement overhang will interfere with the flow of the rock going up. After I make the arch with quartzite I hope to grind it smooth and bring it flush with the fire brick.

Does this make sense in regards to not having the overhang? Will the oven build fit on the cement wall footprint? Maybe I should bring the rock up to the same level as the shelf just incase I need the surface space for oven?

Attached image of a

fire pit. Take note in the forefront I have some of the quartz rock as a border for wood chips. Also in back ground right side is one of the mid size boulders/


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