A half column (also called a pilaster) is a column that's attached to a wall, with half of the column's profile projecting from the wall. The pilaster has a capital at the top, a base at the bottom, and a shaft that's attached to the wall. The pilaster is a traditional architectural element, used to frame entryways, accent walls, and other architectural features.
A PU pilaster is a flat-backed column, with the front half of the column's profile and a flat back that sits against the wall. The pilaster is much easier to install than a full column, because it doesn't need a foundation or a structural core — it's simply glued to the wall with construction adhesive and secured with screws.
The most common pilaster application is a door surround. A pair of pilasters on each side of the door, with a head casing and a cornice or pediment above. The pilasters frame the door and add a classical element to the entry.
A second common application is a window surround. A pair of pilasters on each side of the window, with a head casing and a cornice or pediment above. The pilasters frame the window and add a classical element to the wall.
A third common application is an accent wall. A series of pilasters along an accent wall, with a chair rail or a cornice connecting them. The pilasters add a vertical rhythm to the wall and a classical element to the room.
A fourth common application is a fireplace surround. A pair of pilasters on each side of the fireplace, with a mantel and a cornice or pediment above. The pilasters frame the fireplace and add a classical element to the room.
For sourcing, PU pilasters are a stock product at most factories. The factory offers a range of standard pilaster designs (plain, fluted, reeded, paneled, classical orders) and standard sizes, with quick lead times and competitive pricing. The pilaster can be specified with a matching capital and base, or with a custom capital and base.
A practical install note: a PU pilaster is installed by gluing it to the wall with construction adhesive and securing it with screws into the wall studs. The pilaster should be plumb and square, with the joints at the top and bottom filled with paintable caulk. The painter's topcoat goes on the next day.
A practical note on the design coordination. The pilaster's design should be coordinated with the room's other architectural elements. A fluted pilaster in a modern minimalist room reads as out of place; a plain pilaster in a Federal room reads as understated. The selection should be deliberate, and the pilaster should be part of the room's overall composition.
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Frequently Asked Questions
Q: What are PU columns?
A: PU columns are polyurethane molded columns — typically Tuscan, Doric, Ionic, or Corinthian — that replicate carved stone or wood at a fraction of the weight. They ship in two or three halves for assembly around an internal structural post or as a hollow decorative shell.
Q: Are PU columns load-bearing?
A: Standard decorative PU columns are not structural on their own. They are designed as a 2- or 3-piece shell that wraps an internal load-bearing post (steel, wood, or reinforced concrete). For structural applications, specify "structural PU columns" with an internal steel core — these are engineered and tested to published load ratings.
Q: How tall should decorative columns be?
A: For a standard 8 ft (2.4 m) ceiling, use a 96-inch (2.4 m) column shaft plus capital and base, totaling about 100–104 inches overall. For 10 ft (3 m) ceilings, use a 120-inch shaft. Custom heights are available up to 20 ft (6 m) for atrium and lobby installations.
Q: How do you install Half columns (pilasters) for accent walls and?
A: Mount the base plate to the floor with anchor bolts. If structural, set a steel post first; if decorative, mount an internal PVC pipe for rigidity. Assemble the two or three PU column halves around the post, glue the seams with PU adhesive, and clamp for 30 minutes. Mount the capital and base with construction adhesive. Fill and sand the vertical seam, then paint.