Because slate is stable thermally and chemically inert; many laboratory tables are topped with slate. Which enable those pretty hard to move, too, but they provide a rut for chemists and individuals that work with volatile chemicals to task. It wouldn't do to accidentally drop hydrochloric acid on a wooden table top, but if it happened on a Slate flooring for sustainable Construction one it wouldn't matter.
These aren't huge fire pits; they small yet elegant as a result often the guts piece associated with nice patio furniture set. The modern ones are run be gas and can be fired up and removed from a turn knob end of it. Just use a fireplace starter and enjoy the fun. It's not really a pit much more dug in your yard. Most of them sit on four legs, like a table, more importantly have a ledge surrounding the middle.
Know possibilities. Some homes have Dryvit with mold and water problems.