Outside Corner Blocks: Protecting Wall Edges with Style

An outside corner is where two walls meet at an exterior angle — the corner of a room that projects into the space, the corner of a column, the corner of a chimney breast. Outside corners take more abuse than inside corners, because they're exposed to impact from furniture, vacuum cleaners, and people walking by.

A PU outside corner block is the right answer for two reasons. First, the block protects the corner from impact. The block is a solid element at the corner, made from the same high-density PU as the rest of the trim, and it takes the impact that would otherwise damage the drywall corner. Second, the block simplifies the trim install at the outside corner, replacing a miter with two butt joints.

The standard outside corner block is a square or slightly rectangular block, the same thickness as the trim (crown or baseboard), the same width as the trim's projection, and the same height as the trim's drop or run. The block is the same material as the trim, the same finish, and the same pre-primed surface.

A more developed outside corner block has a small raised panel, a chamfered edge, or a small decorative detail. The block is a feature in its own right, and the design intent is for the block to be seen. Used in traditional and transitional interiors, where the corner detail is part of the room's vocabulary.

A tall outside corner block can extend the full height of the wall, from baseboard to cornice. The block is a vertical element that protects the corner and adds a strong vertical line to the room. Used in formal living rooms, entryways, and any room where a vertical architectural element is part of the design.

For sourcing, outside corner blocks are a standard product at most factories. The blocks are usually sold in matched sets with the crown and baseboard profiles, so the selection is automatic. The lead time is short because the blocks are a stock product.

A practical install note. The outside corner block is the first piece installed at the corner, plumb and square. The crown butts into the top of the block, the baseboard butts into the bottom, and the chair rail (if any) butts into the middle. The joints are filled with paintable caulk, and the painter's topcoat goes on the next day.

A practical note on impact protection. The outside corner block doesn't just simplify the install — it also protects the corner from impact over the life of the building. A PU block at the outside corner takes the abuse that would otherwise damage the drywall, and the block can be touched up with paint if it gets marked. The drywall corner, by contrast, chips and exposes the paper facing, which then peels and requires repair.

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