decorative keystone

A decorative keystone is a polyurethane element, often relief-detailed and protruding, placed at the very top centre of an arch. In classical architecture it is used to accentuate the centre of an arch; it is applied at the upper midpoint of door, window and facade arches. The polyurethane material is light and is applied directly to the surface with assembly adhesive; it resists moisture and impact, does not crack, swell or warp, and can be painted. Being far lighter than its stone counterpart, it is easily installed at high arch points. Because it is mould-cast, the relief detailing repeats identically across every piece. Polure produces decorative keystones in a range of sizes and motif options.