Seven years ago, the stunning plaster interior of the dome of the Clinton County Courthouse was under attack--from water. Previous attempts to seal the dome using traditional caulk and backer-rod materials and methods had failed to provide a lasting solution.

The material exposed to the weather is a factory-controlled and cured bellows of low-modulus silicone.  It is backed by an acrylic-impregnated foam that provides non-invasive anchoring to the stone substrate through adhesion and through compression in the foam matrix.  A small corner-bead of silicone between the silicone bellows and stone further ensures watertightness.  The corner-bead, because of the backpressure of the foam, is never in tension and therefore suffers no adhesion loss as in the caulk and backer-rod option.