Things You'll Need:
- Replacement window
- Plane
- Adhesive
- Saw
- Hammer and nails
- Carpenter's square
- Window caulk
- Caulking gun
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Step 1
Raise the sash and measure the width of the window(s) you want to replace in three places: near the top, in the middle and near the bottom.
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Step 2
Measure the height of the window from the head jamb to the sill, just past where it meets the window stool.
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Step 3
Measure every window you want to replace. Don't assume all of the windows are the same size.
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Step 4
Draw a diagram showing the location of each window you want to replace, showing the measurements.
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Step 5
Pry off the inside stop if it's a traditional double-hung window. There may also be a set of outside stops, which are not removable. Be careful removing the stops, because you can reuse them.
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Step 6
Cut the sash ropes and remove the lower sash.
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Step 1
Set the replacement window in the opening to see if it's a snug fit. There should be no gaps between the window stool and the outside stops. If there is a gap, nail a strip of wood to the window jam to fill the space.
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Step 2
Check to see if the bottom of the window matches the sloped sill of your old window. If not, you must measure the gap between the front lower edge of the new window and the sill. Cut a piece of wood to match the gap, and nail it in place under where the new window will rest.
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Step 3
Center the window in the opening and make sure the window is square by using a carpenter's square.
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Step 4
Shim the sides of the window behind the predrilled screw holes in the jamb.
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Step 5
Pry out the blind stop, which separates the two sashes, and remove the upper sash.
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Step 6
Screw the window into place, and replace the inside stop.
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Step 7
Inspect the window, inside and outside, to make sure it works properly, and then caulk all around it to seal the gap between the window and the outside stop.
