Exterior Keystone Ornament
Polure Exterior Keystone Ornament crowns window arches, door pediments, and facade architraves with classical architectural authority. Precision-molded from rigid high-density polyurethane (150-220 kg/m³), this exterior keystone delivers wood-equivalent mechanical strength without cracking, checking, or adding heavy structural dead weight. Featuring a closed-cell water absorption rate strictly under 1%, it remains completely immune to frost, heavy rain, UV degradation, and biological growth. Rated B2 fire retardant and thermally stable from -100 °C / +80 °C. Installation requires applying a continuous line of polyurethane assembly adhesive on rear contact faces and joinery seams, reinforced with countersunk mechanical screws; silicone adhesives are strictly forbidden. Outdoor joint connections must also be mechanically fastened to each other. Screw heads and joints should be filled with facade filler and sanded smooth using 180-220 grit paper. Pre-primed at the factory with white acrylic primer, it must be finished with UV-resistant exterior paint.
Frequently Asked Questions
What density material is used for Polure Exterior Keystone Ornament?
It is molded from rigid high-density polyurethane (150-220 kg/m³), delivering wood-like impact toughness for arches.
Is Polure Exterior Keystone Ornament weather resistant?
Yes, water absorption is strictly under 1%, resisting rot, frost, and thermal expansion from -100 °C / +80 °C.
How is Polure Exterior Keystone Ornament installed above arches?
Mount using continuous polyurethane assembly adhesive and mechanical screws. Joints must be screwed together. Silicone is forbidden.
What coating is required for Polure Exterior Keystone Ornament?
It arrives with a factory-applied white acrylic primer and must be painted with UV-resistant exterior paint.