How to Fasten Replacement Windows to the Frame
Installing replacement windows is a relatively easy way to transform your home and increase energy efficiency. Modern replacement windows are manufactured in pre-hung, self-enclosed units that are designed to be put right into the frame of the old window opening. They're generally held in by just a few mounting screws through the sides of the frame, along with front and back trim and caulk. Careful measuring when ordering your new windows is crucial, and the old windows have to be removed properly for the installment to go smoothly.
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Things You'll Need
- Tape measure
- Hammer
- Prybar
- Replacement window
- Fiberglass insulation
- Level
- Wood shims
- Long mounting screws (provided with replacement window)
- Screw gun
- Caulk
Instructions
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1
Measure the height and width of the window opening from the inside of the jamb (the flat part of the frame that goes through the wall). Subtract 1/4 inch from each measurement, and order your replacement window with these dimensions.
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2
Remove the old window by using your hammer and prybar to carefully pry out the interior stop-trim that's holding in the window. Don't break the trim, as you'll have to re-use it. Pull the window sashes straight out. Leave the exterior stop-trim in place. Go around the inward-facing side of the frame with your hammer to make sure there are no nail heads or other obstructions that will prevent a proper fit for the window.
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3
Set a strip of fiberglass insulation on the bottom span of the frame. Set the bottom of your replacement window on the frame, on top of the insulation. Push the window into the frame, stuffing more insulation around the edges of it as you do. Push it all the way in, until it's pressing against the exterior stop trim.
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4
Put wood shims on the bottom and sides of the window unit as necessary to level it, holding your level along the top and sides to check.
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5
Use your screwgun to sink the long mounting screws through the sides of the unit and into the surrounding frame, through the provided screwholes. Generally, there will be just two screws per side (top and bottom), though some models will also have one in the middle. Get the screwheads snug against the sides of the window but don't overtighten, as that could pull the sides of the window out of square. Most models don't fasten at all on the top or bottom.
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6
Re-install your interior stop trim to "trap'' the new window unit inside the frame (you can often use the original nails and nail holes). Caulk all around the perimeter where the window unit meets the frame on the interior and exterior.
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Tips & Warnings
Wear goggles during your ripout of the old window, and while you're using your screwgun.
