Starlite was a material invented in the 1960s that allegedly withstood 10,000°C temperatures.

Here, NighthawkInLight shows his copycat of the secret recipe, withstanding a still whopping 2000°C at less than 1" thickness.

The way it works: when exposed to high temperatures, it expands, creating a carbon foam barrier that pushes the heat away while forming an insulator.

The Recipe:

2 parts Flour
1 part Corn Starch
1 part powdered Sugar
1 part Borax
1.5 parts Water

When mixed and formed and let dry, you have a fireproof tile with heat resistance claimed to be on par with alumino fire brick, while protecting against both insects and mold.
Maybe worthwhile to coat with a resin for extra weather resistance if making tiles for a fire shelter. Maybe an idea to retrofit a room in the house with panels of this on steel studs, I don't know. Get creative.

Good luck and Godspeed