Hearth pad
A hearth pad is the noncombustible floor protection under and around a wood stove — stone, tile, or a listed board — that guards the floor against embers and radiant heat. The stove's listing specifies the required size and thermal rating (ember protection only, or a specific R-value).
Requirements differ by stove: models with low bottom-heat output need only ember protection, while others require insulating pads with a minimum R-value. The pad must also extend defined distances beyond the stove's sides and loading door (commonly 8 inches at the sides and 16 inches at the front under US listings).
A rug is not a hearth pad, and neither is sheet metal alone when an R-value is required — check the manual's floor-protection section before installation.