Can you mortar firebrick onto a concrete slab?

[Mr Greenbee]

Hi,

New to this forum! I'm going to build an outdoor kitchen where I will cast a concrete countertop. At one end of the counter, I plan to lay firebrick directly on the concrete and then up towards each wall to create a fireplace in the corner. The walls at the intended fireplace will be built with leca. Attached is a drawing.

Will the concrete countertop crack due to the heat, or will it hold up if the mortar is fireproof?

 

[jonwal01]

How did the project go, did you build according to this and has it worked? I'm considering a similar solution myself.

 

[Mr Greenbee]

How did the project go, did you build according to this and has it worked? I'm considering a similar solution myself.

I chose to build a shelf with a thin metal sheet, then vermiculite boards, and on them firebrick. Then I will cast a concrete countertop that instead fits into the square that the firebrick forms. In other words, I avoided placing firebrick on concrete, as I didn't want to risk cracks.
Turned out really well!