How to Build Framing for Exterior Windows
The windows in your home hang in casings, or borders of wood, that are set into the window openings in the walls. The casings have to be adjusted during installation so they're level and square. This requires some space between the casing and the wall. The window frame covers that space and visually dresses out the window. There are several ways to fit the frame together, including mitering at the corners.
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Things You'll Need
- Hammer
- Prybar
- Tape measure
- Pencil
- Wood trim (flat)
- Miter saw
- Trim nail gun
- Caulk
Instructions
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1
Measure across the upper span of the opening, from corner to corner, right along the edge of the window casing -- the border of wood around the window that meets the wall.
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2
Transfer the measurement to a length of trim, making two marks, one of them six inches in from the end, and the other one measured off the first one by the measurement you took. Make the marks on the bottom edge of the trim.
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3
Lay the trim on a miter saw with the face up and the marked bottom edge against the back rail of the saw. Position the trim so one mark is under the blade.
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4
Turn the blade to point 45 degrees toward the closest end of the trim -- away from the measured section. Make the cut.
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5
Slide the trim so the the second mark is under the blade. Swivel the blade to point 45 degrees toward the closest end, which will be in the opposite direction as before. Cut it.
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6
Hold the trim to the top of the window opening, with the bottom edge lined up along the window casing and the mitered ends angling up and out at the two top corners. Secure the piece with your trim nail gun, shooting the nails every foot along the top and bottom edges of the trim.
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7
Repeat for each of the other sides of the window. The mitered ends of the trim will butt to one another at the corners.
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8
Caulk the edges of the trim wherever it meets the wall or casing.
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