A window trim upgrade is similar to a door trim upgrade, with the addition of the stool and apron details that are specific to windows. The window is a major visual element in any room, and a thoughtful trim treatment turns the window from a hole in the wall to a designed feature.
The simplest window trim upgrade is the addition of a casing. A PU casing, 80 to 150 millimeters wide, applied to the window frame around the opening. The casing frames the window, adds visual weight, and the room reads as more finished.
A more developed window trim upgrade is the addition of a complete surround. A head casing, side casings, a stool, and an apron. The surround is a substantial architectural element, and the window reads as a designed feature.
A more developed window trim upgrade is the addition of a cornice. A small PU cornice applied above the head casing, with a flat or stepped profile. The cornice adds height to the window treatment, and the window reads as more substantial.
A more developed window trim upgrade is the addition of a pediment. A PU pediment applied above the window, with a classical triangular or segmental shape. The pediment adds a substantial classical element to the window, and the room reads as more formal.
A more developed window trim upgrade is the addition of a full surround with pilasters. PU pilasters applied to each side of the window, with a substantial head casing, a cornice or pediment above, and a stool and apron below. The surround is a major architectural element, and the window reads as a designed focal point.
For sourcing, the right conversation with the factory is about the window size, the design style, and the level of upgrade. The factory can supply any of the above options, from a simple casing to a full surround with pilasters. Custom sizes are available on longer lead times.
A practical install note: the window trim should be planned around the window's existing condition and the room's style. A window in a modern room gets a simple, clean casing; a window in a traditional room gets a developed surround with a cornice or pediment. The trim should be coordinated with the room's other trim (baseboard, chair rail, crown).
A practical note on the stool depth. The stool is the horizontal trim at the bottom of the window, inside the casing. The stool is typically 100 to 200 millimeters deep, providing a small ledge at the bottom of the window. The depth should be proportional to the window's size — a larger window gets a deeper stool, a smaller window gets a shallower stool.
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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.