polyurethane keystone ornament

A polyurethane keystone ornament is a decorative element inspired by the keystone form, placed at the top of door and window arches. In classical architecture it is used to create emphasis at the central upper point of an arch and is applied together with a surround set. The material is lightweight and bonds directly with mounting adhesive; it resists moisture and impact, will not crack, swell or warp, and takes paint well. On exterior facades, unlike plaster it is unaffected by moisture and temperature changes, and unlike timber it does not rot. Because each piece is cast from a mould, the relief detailing repeats identically across every unit. Polure produces keystone ornaments in a range of sizes and motifs.