If you prefer to face your home with a natural material, sliced rock is a good, noncombustible option. Use a fire-rated mortar, like MetaCaulk, and periodically repair cracks to lessen the likelihood that the heat of a fire will cause the stones to pop off. The fire resistance of Natural Stone Veneer International's fieldstone veneer is amplified if it sheathes masonry-block or ICF framing instead of wood framing that hasn't been treated with fire-retardant chemicals. Natural Stone Veneer International;
$8 to 14 per square foot.