A premixed gas burner has a hollow body including a closed end and an entry end into which a combustible gas and air mixture may flow. The body has a multiplicity of apertures through which the mixture may pass from the hollow interior. A burner portal deck is positioned in superposed relationship over the apertures for permitting the gas air mixture to form a controlled flame. A porous woven fabric formed from ceramic fiber having high thermal insulation properties is located above the deck and separates the deck from the flame front formed when the mixture is ignited. The fabric insulates the deck from excessive temperatures, prevents flash back, allows use of conventional stainless steel for the deck and body components and makes possible the manufacture of long burner sections. A long burner section has a number of decks in side-by-side relationship with an insulating fabric mat over the decks for not only providing insulation, but also forms a gasket between the adjacent decks.