Hearth

The inner hearth sits under the fire itself and takes direct heat, while the outer hearth is the extended slab or paved section in front of the fireplace opening that catches stray embers and sparks before they reach carpet or wood flooring. Both sections need a solid masonry base rather than just a decorative surface layer over wood framing, since looks alone don't provide real fire protection if there's nothing fireproof underneath.

Hearths get built from brick, stone, or tile set over a masonry or concrete base, and the choice often comes down to matching whatever stone or brick is already used elsewhere in the room. The outer hearth has to extend out far enough in front of the opening and to each side to meet fire code clearances, which depend on the size of the fireplace opening itself. On outdoor fireplaces and fire pits, the same fireproof-base principle applies even though there's no surrounding wood floor to protect.