Polyurethane Semi Circular Arch Pediment with Central Keystone

The P1456D75VID semi-circular arch pediment is a structural-style decorative element designed to frame door headers, window tops, and interior passageways. Measuring 1150 mm in width, 671 mm in height, and projecting 170 mm from the wall, this architectural feature creates a classic portal effect. It introduces a curved transition to flat walls, transforming standard square openings into grand, classical entryways.

Engineered from a high-density rigid polymer with a rating of 150-220 kg/m³, this arch offers the physical toughness of wood without the vulnerability to moisture, rot, or wood-boring insects. Assess water and moisture exposure using the product technical data, surface finish and installation details. Unlike heavy concrete or natural stone alternatives, its lightweight nature prevents structural strain on building facades while ensuring long-term durability.

Visually, the arch features a multi-tiered, stepped profile that curves symmetrically to meet a prominent, trapezoidal keystone at the center apex. This central block adds a focal point of classical architectural order. The smooth, pre-primed white surface is ready to receive paint, allowing the detailed shadow lines of the concentric curves to stand out sharply under both natural and artificial lighting.

This versatile component is widely implemented in premium European residential and commercial projects. It is ideal for exterior window pediments on classical facades, main entrance door surrounds, grand hotel lobby corridors, and interior wall niches. When paired with vertical pilasters or flat architrave mouldings, it forms a cohesive, high-end framing system for portals of various scales.

For installation, the dry and clean surface must be prepared before applying polyurethane (PU) assembly adhesive along the mounting edges. Mechanical fastening with screws is mandatory to secure the arch while the adhesive cures. Joint lines can be finished with a suitable exterior-grade filler and sanded smooth. While the factory-applied primer prepares the surface, applying an additional primer is optional and depends on your choice of paint manufacturer guidelines. Outdoor applications require a high-quality UV-resistant paint finish to prevent discoloration.

Combining the refined detail of traditional plasterwork with the modern resilience of advanced synthetics, this arch pediment is a low-maintenance, high-impact solution. It provides architects and interior designers with a reliable, easy-to-install decorative trim that stands up to harsh weather conditions and high-traffic interior environments alike.