Precast Concrete slabs

[enkaynj]

Hi Folks,
New to the forum. Planning to install a backyard pizza oven. I see a lot of folks cast their own concrete slab for the floor of the hearth. Me being lazy (and impatient), I was wondering if I could use a precast slab like the one found in this link.
Equipment Pads by DIVERSITECH - A/C Mounting Pads at Zoro
Does anyone have any advice as to why I can / can not use this ?
Thanks in advance.

[NCMan]

Re: Precast Concrete slabs

I would not recommend using something like that. They are not designed for the use you are considering. They don't appear to be of sufficient thickness or width/depth. They also are designed to be sitting on a solid base, such as the ground, etc., not to span over an unsupported space. Just my 2?.

[dakzaag]

Re: Precast Concrete slabs

Pre-cast is fine as long as it is designed to support the load. Remember you are typically spanning between two walls, so the slab must support itself and the weight of the oven. An AC unit probably weighs the same as your oven floor and the pad is only designed to sit on the ground, not bridge two supporting walls.
You could kill yourself building an oven if you try hard enough. (kinda blows the lazy confession out of the water...)

[Tscarborough]

Re: Precast Concrete slabs

I used 4 similar to those, with several caveats: My base was built such that there was very little bridging needed, and the pads I used had wire in them.

Those say they can support 125 pounds per square inch which is well below the load of an oven, BUT that is the compressive, not the flexural strength.