Through how much concrete can a Zircon MetalliScanner MT6 find rebar?

If you drill into concrete without going through the scanning process, you won't know for sure if something will be hit. For instance, if you hit post-tension cables or rebars, you can create a significant compromise on structural stability. You also risk cutting into water lines or electrical conduits, which could cause power outages or, worse, electrocution and explosion. This can cost you time, money, and injury to workers.

Concrete scanning involves the use of ground penetrating radar (GPR) to survey the location of voids, conduits, rebars, post-tension cables, and anything else within the concrete that is invisible to the open eye. It helps you make informed decisions before doing any extensive project that could harm your property or any workers present onsite.

Figure 1 90 lb. bag per square ft., 6" deep.
Don't forget sand to grade and rebar to reinforce.
You probably won't find enough guys to mix all that concrete, so you'd really be better off hiring a concrete truck.
Tip: It's best to over estimate a little so you won't be caught short.

Take it to an electrical place to be checked out .

Hi
Thanks for the video. I appears that you have concrete floors in your home. A couple of things that drasticly reduce wifi distance or signal strength is electrical fields caused by wiring in the walls and concrete walls or floors. Concrete is very dense and also has a lot of metal rebar in it for structural strength. This combination is very tough to penetrate with radio signals. The best thing you could do is either mount the router higher in the first room you showed so that it is at a level about even with the floor of the second level or add a repeater somewhere on the second floor. Mounting the router higher allows the radio waves to bounce around both levels without having to go through the concrete and rebar between them.

A rebar locator is used to find and locate rebar reinforcements in a wall, usually made of concrete.

rebar are steel rods that are used to reinforce concrete, usually found in buildings.

The concrete and metal rebar in building block any signals to the radio hence the squelch comming on and wont go off, And you blocked to the repeater your using.