A PU architrave is a factory-made trim assembly that surrounds a door or window opening, designed in a classical European vocabulary. The architrave is typically more substantial than a standard casing, with a developed profile, multiple layers, and classical details.
The most common PU architrave is a three-layer assembly. A base casing (80 to 120 millimeters wide), a secondary casing (30 to 60 millimeters wide) applied on top of the base, and a top casing (10 to 30 millimeters wide) applied on top of the secondary. The three layers create a substantial architectural surround, with the classical vocabulary of the profiles creating the visual character.
A second common PU architrave is a single developed profile. A wider casing (150 to 200 millimeters) with a classical profile (a cyma, a torus, a small bead or dentil). The single piece has the same visual weight as a three-layer assembly, with a simpler install.
A third common PU architrave is a surround with a plinth block at the base. A standard casing, with a plinth block (80 to 150 millimeters tall) at the base of each side casing. The plinth block terminates the casing cleanly at the floor, and the surround reads as a designed classical element.
A fourth common PU architrave is a surround with a small pediment above the head casing. A standard casing, with a triangular or segmental pediment above the head. The pediment adds a classical element to the surround, and the door or window reads as a formal entry.
For sourcing, PU architraves are a stock product at most factories that produce classical trim. The factory's catalog typically has 10 to 30 standard architrave designs, with a range of profiles and configurations. Custom designs are available on longer lead times.
A practical install note: the PU architrave is installed in layers, with each layer applied after the previous one has set. The base casing is installed first, with construction adhesive and finish nails. The secondary casing is installed second, aligned to the top edge of the base. The top casing is installed third, aligned to the top edge of the secondary. The joints are filled with paintable caulk at each stage.
A practical note on the right architrave for the right room. The architrave's design should be coordinated with the room's overall style. A classical architrave in a modern minimalist room reads as out of place; a modern flat casing in a classical room reads as understated. The selection should be deliberate, and the architrave should be part of the room's overall composition.
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Frequently Asked Questions
Q: What is polyurethane (PU) decorative material?
A: Polyurethane (PU) decorative material is a high-density closed-cell polymer molded into architectural profiles such as cornices, ceiling medallions, wall panels, columns, and skirting boards. It replicates the appearance of plaster, carved wood, or stone at one-quarter the weight, is fully waterproof, impact-resistant, and arrives factory-primed for paint.
Q: How does PU compare with plaster and wood mouldings?
A: PU is lighter than plaster (no scaffolding required), impact-resistant during transport, and immune to cracking. Compared with wood, PU does not warp, split, or attract termites, and it tolerates moisture in bathrooms and kitchens. The trade-off: PU cannot be refinished the way solid wood can, but its lifespan is 20–30+ years with minimal maintenance.
Q: How do you cut and finish PU mouldings?
A: Cut PU mouldings with a fine-tooth miter saw (40+ teeth for a 10-inch blade) to avoid chipping the molded edge. Sand the cut edge with 220-grit, then apply two coats of interior latex paint. Mitre joints at corners, fill seams with lightweight spackle, sand smooth, and finish with one final top coat.
Q: Is PU moulding safe for indoor air quality?
A: Yes. Premium PU mouldings are manufactured without formaldehyde, asbestos, or VOCs. They meet EN 13501-1 Class E fire classification as a minimum, with Class B fire-retardant versions available for commercial projects. The factory-applied water-based primer further reduces off-gassing once installed.