Abstract: A radiant gas burner construction is disclosed which utilizes a gas combustion mixture plenum closed on one side by a porous refractory matrix. The matrix is supported in the plenum by a plurality of clamping clips that extend about the marginal edge of the matrix and have inturned lips that engage the edge thereof, the clips being fastened to the external portion of the plenum. Non-combustible gas supply enclosures are provided that discharge a non-combustible gas around the edge of the combustion gas plenum by using plates that are spaced slightly away from the edge of the combustion gas plenum so that the non-combustible gas will be discharged down along the side of the gas plenum and then toward the free edge of the matrix adjacent the burning face thereof, or alternately into the edge of the matrix below the supporting clips so that an air seal is provided around the peripheral portion of the matrix.