Learn how to install replacement windows frame and sash. This article includes measuring for new windows, preparing the existing window frame for the new replacement window frame and installing the new windows.
Steps covered are removing the interior and parting stops, the old sashes and hardware, insulating the opening for the sash weights and the gap around the new frame, leveling and installing the frame and reinstalling the interior stops.
Directions on How to Install Replacement Windows Frame and Sash
Do you need to know how to measure and install frame and sash replacement windows? This fairly easy and straightforward process can be handled by just about any beginner. Read the easy steps below on how to install replacement frame and sash windows.
Replacement frame and sash windows offer an easy way to replace existing windows without removing the old window frame, moldings or siding. It’s less work than full replacement window installation, easy enough for most beginners and the bulk of the work takes place inside. This is how to install replacement frame and sash windows.
Measuring for Frame and Sash Windows
You may need to remove the interior stop in order to measure accurately. Use a putty knife to slip behind the stop and gently pry it loose from all four window sides. Be as accurate as possible while measuring.
Measure width between the side jambs at the top, the middle and at the bottom. Do the same for the height of the window, measuring on the left side, the middle and right side between the top jamb and the sill. This is different than measuring for full replacement windows where the rough jamb opening is measured.
Use the smallest measurements for ordering your replacement frame kits. If you removed the stops for measuring, replace them until the new windows arrive.
Preparing for Installation
Wear a dust mask and safety glasses. Old windows are often painted with lead paint and the dust should not be inhaled. Remove the interior stop using a stiff putty knife to get between the stop and the jamb and pry it loose. Be careful not to damage the stop or the molding surrounding the window frame. You will need the interior stop to complete the installation.
If your window sashes have ropes with weights, cut the ropes near the opening. Otherwise, remove the channels or hardware the lower sash moves up and down on and then remove the lower sash.
Pry the parting stop away from the jamb with a flat pry bar. Cut the rope weights or remove the upper sash hardware and remove the upper sash. Check the window opening for nails, screws or other pieces of hardware. Stuff insulation in the weight holes if possible.
How to Install Replacement Windows Frame and Sash
Place a bead of exterior caulk between the blind stop and the window jamb, and along the back of the stool. Set the bottom of the new replacement window frame on the window sill and tilt the window into the opening tightly against the blind stop.
Place a level on the lower part of the new frame. If necessary, use shims to adjust one side of the window frame up. Once the bottom of the frame is level, install the screws that hold the frame in place but only put them in far enough to hold the frame. Leave plenty of adjustment room.
Hold the level against the sides and adjust them in or out with shims until they are level. Measure diagonally between opposite corners to check for square–both measurements must be the same or the window won’t seal properly. Keep measuring and adjusting until the window frame is perfectly square.
Finishing the Installation
Tighten the installation screws until they are snug, but don’t over tighten. Just snug them up. Place insulation in any gaps that show, and underneath the window. Test the fit by sliding the sashes up and down. They should function smoothly, meet evenly and not show uneven gaps at the top or sides.
Caulk the outside of the frame where it meets the blind stop. Stuff insulation into the gap between the frame the existing sill. Most frame and sash window inserts come with a filler strip to install over this gap.
Installing the interior stops completes how to install frame and sash windows. Nail the old interior stops against the new frame with finishing nails or cut new ones to replace them.