How to Trim a Window Exterior
- 1). Measure across the top of the window. Transfer the measurement to the bottom edge of a piece of trim, putting two marks and leaving 6 or more inches beyond each.
- 2). Set the trim on a miter saw with marked edge facing the blade and one of the marks directly in front of it. Swivel the blade 45 degrees, pointing away from the main span of the trim. Make the cut.
- 3). Move the other mark under the blade. Swivel it to 45 degrees in the opposite direction. Make the cut. The top of the trim will be longer than the bottom.
- 4). Hold the cut piece of trim along the top of window, with the smaller side down. The two miter cuts should start at the two corners and span up and out. Secure the board by shooting in nails with your nail gun along the top and bottom edges, every foot or so.
- 5). Repeat the process of measuring and cutting each board for each side of the window. Secure them in the same manner, with the mitered cuts butted against each other to form the corners.
- 6). Caulk along the whole perimeter of the trim, on both sides of each piece and along the mitered lines, using a caulk gun. Let the caulk dry for 24 hours.
- 7). Paint the trim, using a paintbrush.
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