How to Replace a Window Without Removing the Old Frame

Window replacement can save on energy costs and can improve the aesthetics of a home. It is most common to replace old windows without removing the entire framework. If the framework already in place is solid, leaving it as it stands makes for a cheaper and easier window replacement.

Difficulty: Moderate

Instructions

Things You'll Need:

• tape measure
• hammer
• drill
• screwdriver
• pry bar
• chisel
• utility knife
• caulk
• square or level

1. Using the tape measure, measure the existing window from the bottom sill to the top frame, just to the jambs. This will give the size of replacement window that you should purchase.

2. Remove the stops from the window by gently using the pry bar. These are the thin pieces of trim that are found at the sides of the window, usually quarter round or similar thin trim. They will be reused on the new window, so save them for later.

3. Now comes the time to remove the windows themselves, which are known as sashes. The inside sash needs to be removed first, followed by the outside. Care should be taken not to damage the window sill or jambs since these will be kept in place.

4. Clean up the jambs, including pulling any nails and scraping any old caulk from the area. If there are any holes present, these should be filled using caulk.

5. Use the caulk gun to lay a bead of caulk along the outside stops and along the sill.

6. Place the header on top of the window and caulk the top of it.

7. Place the window into the frame against the new caulk bead. Use the square and level to check the window and be sure that it is plumb and even all around. If small gaps are present, use shims to even out the window and secure it into place.

8. Use the mounting screws provided to secure the window to the jambs. They should be secure, but not overtightened.

9. Slide the header to the appropriate position against the top jamb and secure it in place with mounting screws.

10. Check the operation of the sills and be sure that they slide easily up and down. Adjust the window as necessary for proper function.

11. Finally, caulk the inside of the window and replace the stops that were removed earlier.

Tips & Warnings

• Be sure to measure properly, both before ordering windows and after they arrive.
• Try placing the window in the opening when they arrive to be sure it will fit
• It is difficult to find exact size windows, particularly for older homes with odd sizes. Always go a little under the measurement if exact sizes aren't possible. A too-small window can be adjusted with shims, but a too-big window can not be fixed.