Vinyl replacement windows provide a significant upgrade to your home. They seal out the weather better than old windows and look better too. The steps for how to install vinyl replacement windows in a wood frame are meant for experienced do-it-yourselfers. Vinyl windows should only be installed in frames free of rot. You also need an opening that is not warped in any way. An out-of-square frame will result in leaks, drafts, or a window that is difficult to open and close.

How to Install Vinyl Replacement Windows in a Wood Frame Steps

1. Examine existing wooden window frame to confirm that it’s not out of square or rotting.
   1. Measure the frame diagonally twice like an X. If the measurements are equal, then the frame is square.
   2. The presence of rot or differing diagonal measurements indicates that the frame requires rebuilding.
2. Measure the width and height of the opening and buy vinyl replacement windows of the corresponding size.
   1. Take three measurements in both directions and use the smallest figure to determine new window size.
   2. Width is measured between the interior trim edges.
   3. Measure height from the highest point of the sill to the top.
3. On the inside, cut any caulk or paint around the old window with a utility knife.
4. With a pry bar or putty knife, gently remove the inside window stop without breaking it.
5. Set stop aside to attach after completing the steps for how to install vinyl replacement windows in a wood frame.
6. Take out the lower window sash.
7. Pry out the old parting stop along the top and discard.
8. Lift away the top sash of the old window.
9. Pull out the sash liner and all old components of the pulleys, cords, and weights.
10. Pack some fiberglass insulation into the empty sash pockets.
11. Scrape off any old paint or caulk clinging to the frame.
12. Run a bead of caulk around edge of frame and two beads of caulk along the sill.
13. From the inside of the house, lift the new window into place.
14. Press the new window tightly against the exterior window stop.
15. Place shims behind the holes for mounting screws.
16. With a power drill, drive a mounting screw on each side.
17. Take the measuring tape and check to ensure the window is square with two diagonal measurements.
18. If window is not square, add shims and adjust as necessary.
19. Drive the remainder of the mounting screws.
20. Run a bead of caulk around interior edge of frame.
21. Reattach the old window stops.
22. Head outside and apply caulk around the edges of the new vinyl window.
23. Attach the new pieces of vinyl trim.