If you have older wooden double-hung windows that move up and down, or sliders that open by moving left and right, sooner or later you'll likely have issues with the windows sticking and refusing to open and close smoothly. In most cases, the fix for sticking windows is simple and inexpensive.
Why Windows Start to Stick
Structural settling of the house may be causing the window framing to pinch the windows, or the window sashes themselves may be bowing due to age. In these situations, the best solution is to remove the entire window, reframe the opening, and install an entirely new window.
Fortunately, this serious fix is usually unnecessary. Windows that refuse to slide in their tracks can often be remedied by cleaning the window tracks, scraping off paint, lubricating the tracks, or lightly sanding the tracks.
Equipment / Tools
- Putty knife
- Utility knife
- Clean cloth
- Shop vacuum
- Silicone lubricant
Clean Window Tracks
Ordinary dirt and grime can increase the friction and cause windows to bind in their tracks. Vacuum the tracks to remove all dust and dirt, then wipe them clean with a clean cloth moistened with furniture wax (for wood windows) or a household cleaner (for vinyl-track windows). This simple step alone may restore your windows to efficient operation.
Inspect the window tracks for dried paint. Windows tracks are not meant to be painted, but they often are, and if the previous paint job was sloppy, it may have left paint drips in the wooden tracks.
Older paint may crack and peel, increasing the friction in the tracks. In this case, scraping away loose paint and lightly sanding the window tracks may loosen things up enough to allow the window to move freely.
Put the sandpaper on a wood sanding block to ensure that the sandpaper is flat when you are using it.
If you choose to paint window tracks, make sure you first scrape away the old paint, sand thoroughly, and apply a very thin coat of paint.
Break Paint Seal
The wooden windows may have been painted shut inside their tracks, in which case the windows won't budge at all. Trying to break the paint seal by lifting the window not only doesn't work but you risk damaging the window this way.
You usually can break the paint seal between the sash frame and the channel with a sharp utility knife, putty knife, or a tool known as a paint zipper, designed for this purpose.
Lubricate Wood Tracks With Wax
Once you have cleaned the window tracks, you can lubricate the window channels by rubbing the wood surfaces with ordinary wax, such as that from a white candle. A light coat is all it takes. Open and close the window several times to distribute the wax and lubricate the surfaces. Cleaning the tracks and applying the wax once each year will keep your windows operating smoothly.
A common solution but a poor one is to lubricate the window tracks with penetrating oil, such as WD-40. Oils will offer only a temporary solution and will soon serve as magnets for dust and grime, making your windows stickier than ever. Never use oil products on either wooden or vinyl windows.
Lubricate Vinyl Window Tracks With Silicone Lubricant
On vinyl-track windows, the solution to sticking windows is to remove the window sashes, then clean the vinyl tracks and lubricate them with a thin layer of silicone lubricant applied by wiping it on with a clean cloth. Repeat this routine maintenance once each year.
Repair or Remove Sash Cords
On older wooden double-hung windows, a system of cords and pulleys attached to metal weights inside the frame openings are used to counterbalance the weight of the window and allow it to move up and down easily.
When the lower window is hard to lift upward in its channel—or if the window won't stay in place and slams shut sharply—it may be because the cord-and-weight system is malfunctioning. Most often, this is because the cords that link the pocket weights and the window sash have broken. The solution is to remove the window sash and repair or remove the broken sash cords.