How to Unstick a Window

Windows are often trouble spots. Along with doors, windows are the major source of heat-loss in most homes. They also may stick shut when they're painted or swell shut from humidity. Inside, shades and venetian blinds may not work right, glass gets broken, and screens get torn. In this article, we'll discuss what you can do to keep your windows working properly. One common problem that homeowners or apartment-dwellers will encounter are windows that won't open.

Unsticking a Window

Double-hung wood-frame windows, especially in older homes, often stick. The most common cause is that the window has been painted shut and the paint has sealed it closed. The solution is usually simple: Break the seal, and clear and lubricate the sash tracks.

What You'll Need
Here are the tools to have on hand to unstick a window:
  • Stiff putty knife or paint scraper
  • Hammer
  • Chisel
  • Medium-grade sandpaper
  • Sanding block
  • Silicone lubricant
  • Block of scrap wood
  • Small pry bar

Opening a window that has been painted closed takes strength, but it isn't difficult. Here's how to unstick a window:
Step 1: Before you start to work, make sure window is unlocked.

Step 2: Look for evidence of a paint seal between sash and window frame. To break seal, push blade of stiff putty knife or paint scraper into joint, cutting straight in through paint. If necessary, lightly tap knife with hammer to force blade in. If window was painted on outside, repeat procedure to break seal on outside.

Step 3: If window still doesn't open, check tracks in window frame above sash; they're probably blocked with built-up paint. Using hammer and chisel, carefully clean excess paint out of window tracks. Cut out thickened paint, but be careful not to gouge the wood of the tracks. Smooth cleaned-out tracks with sandpaper on a narrow sanding block, then spray them with silicone lubricant.

A really stuck window may require using a small pry bar to open it.
©2006 Publications International, Ltd.
A really stuck window may require
using a small pry bar to open it.
See more window fixing pictures.

Step 4: If window still sticks, the paint in lower part of tracks is probably holding it. Set block of scrap wood against sash at window frame. Gently tap block of wood with hammer to force sash back from frame. Move block of wood all around window sash, tapping sash back from frame; then try window again. If it opens, clean and sand tracks, and lubricate them with silicone spray.

Step 5: If window still doesn't open, use small pry bar on it, preferably from outside. Insert flat end of pry bar under sash; set block of scrap wood under it for better leverage. Pry gently at corners of sash and then from corners in toward center. Use pry bar very carefully; too much pressure could damage both sash and frame. If window opens, clean and lubricate tracks with silicone spray. If it still doesn't open, sticking may be caused by extreme humidity, poor construction, or uneven settling. Call carpenter to fix window rather than trying to force it open.

Windows receive a lot of use while protecting your home from the heat and the cold, so from time to time the glass might break or crack. Learn how to handle this type of window repair in the next section.