A brick hearth system includes a rigid containment shell in which a concave bottom is lined with a hearth refractory sub-layer and hearth brick working layer. The outer perimeter of the hearth refractory is ringed with thrust blocks to compress the whole toward the center and to thereby deny gaps from forming between the separate bricks. Many individual thrust rods penetrate the outer bottom of the containment shell, and such are used to transmit compression forces generated outside the shell to be applied against the thrust blocks in unison. Each thrust rod receives an adjustable amount of inward force from a spring, acting either directly or through a beam or rocker arm. These are anchored to and use the hoop strength of the containment shell as leverage. As the hearth brick working layer grows during its service life, the ring of thrust blocks grows in diameter as well inside the margins provided within the containment shell. The individual thrust rod springs are periodically adjusted to keep the pressures in the optimal range.