In this video, This Old House general contractor Tom Silva shows how to free a painted-shut window.
1. Unlock the sash and then use a 5-in-1 painter's tool to break the paint seal that's adhering the sash in place. Gently tap the painter's tool with a hammer.
2. Cut through the paint seal along both vertical sides of the sash, along the stool at the bottom of the sash, and at the meeting rail where the two window sash meet.
3. As you tap the painter's tool, have an assistant hold the vacuum hose directly below to catch all paint dust and chips.
4. Move outside and repeat the process, cutting the paint seal around the entire sash.
5. Slip a flat pry bar underneath the sash, directly in line with the window's vertical stile. Gently pry up until the sash breaks free.
6. From inside the room, raise and lower the sash a few times to see how smoothly it slides.
7. Next, use a utility knife to slice through the paint that's sealing the stop bead to the window jamb. Repeat for the opposite stop bead.
8. Pry both stop beads from the window using the painter's tool. Again, collect the dust with the vacuum.
9. With both stops removed, pull the sash free from the window frame and set it aside.
10. Unscrew and remove the access door from each side jamb, then pull out the old sash weights. 11. Pry the old sash cords from the sides of the window sash.
12. Feed a new length of sash cord over the pulley on each side jamb and down into the wall cavity.
13. Tie the sash weights onto the new cords and drop them back inside the wall. Replace the access doors to conceal the sash weights.
14. Set the sash partially into the window opening. Pull one of the sash cords until the sash weight hits the pulley, then lower the weight about 3 inches.
15. Secure the sash cord to the side of the sash with two ¾-inch screws. Repeat to attach the second cord to the opposite side of the sash.
16. Trim off the excess cord with a utility knife.
17. Lubricate each piece of metal weatherstripping, then slip them between the sash and the side jambs.
18. Secure the weatherstripping to the side jambs with small brad nails.
19. Reattach the stop beads with 1½-inch finishing nails.
20. Test the operation of the window.