This 18"x 48" Black Hearth Extension is approximately 1" thick and very rigid. It protects floors fro intense heat, hot coals, ashes and soot that wood and coal stoves can produce. A HY-C Stove Board/Hearth Extender will protect the floor from heat and sparks in front of your fireplace or beneath, in front and around a wood burning stove. Constructed of embossed printed steel over 1/2" thick specially formulated fiber board which is non-combustible. It may also be used as a wall shield to protect walls from intense heat.