How to Construct Contemporary Window Trim
- 1). Measure the width along the top of the window opening, from corner to corner, using a tape measure.
- 2). Transfer the measurement to a piece of trim, making two marks on the lower edge of the trim with a pencil and leaving space beyond each of them.
- 3). Set the trim on your miter saw facing up, with the bottom edge facing the saw blade. Line up one of the marks with the blade. Swivel the blade outward (pointing away from the middle of the trim) by 45 degrees. Make the cut.
- 4). Slide the second mark under the blade. Swivel the blade to point 45 degrees to the other side, so it's against pointing away from the center of the trim. Make the cut.
- 5). Position the cut trim over the top of the window opening, with the bottom edge lining up along the casing and the two angles at the ends flaring up and out over the corners of the opening. Secure the piece with trim nails and a hammer, putting in nails every 10 or 12 inches along the top and bottom edges of the piece.
- 6). Repeat the process for each of the spans of trim around all four sides of the window, butting the mitered ends to one another to form the corners.