Polyurethane Keystone
Polure polyurethane keystone brings classical architectural focal points to door architraves, window surrounds, and facade arches. Molded from high-density rigid polyurethane (150-220 kg/m³), this decorative accent piece delivers wood-like mechanical toughness while remaining lightweight for single-installer positioning. Its closed-cell physical core ensures water absorption stays below 1%, making it completely immune to moisture, frost cracking, and mold growth on exterior facades or humid interiors. Rated B2 for fire safety and thermally unyielding between -100 °C / +80 °C, it comes pre-primed with factory white acrylic. Installation requires clean, level substrate surfaces. Apply a continuous bead of polyurethane assembly adhesive on contact faces; silicone sealant is strictly forbidden. Mechanical screw fixing is required for permanent installation; countersink screw heads, fill with facade putty, sand smooth with 180-220 grit paper, and finish with water-based interior paints or elastic UV-resistant exterior paints.
Frequently Asked Questions
What material is Polure polyurethane keystone made from?
It is molded from high-density rigid polyurethane (150-220 kg/m³), offering wood-like impact toughness and B2 fire class safety.
Is polyurethane keystone suitable for exterior window and door surrounds?
Yes. Water absorption is under 1%, ensuring it will not crack from frost, rot, or mold when exposed to outdoor weather.
How is polyurethane keystone installed?
Mount using PU assembly adhesive and screws (silicone is forbidden). Fill screw holes with putty, sand smooth, and paint.
What paint should be applied to polyurethane keystone outdoors?
After light sanding (180-220 grit), apply elastic UV-resistant exterior paint to protect against weathering and sun fading.