Fixing Stuck Sash Windows

  • 1-3 hours
  • Beginner
  • 0-50
What You'll Need
Utility knife
Screwdriver or power drill
Rubber mallet

Sash windows are very common on older homes. They consist of a frame that surrounds two halves. Each sash is a window pane with its own frame. The top sash is usually fixed, while the bottom sash slides up and down to open and close. For numerous reasons, sash windows can get stuck. Expansion of the wood due to humidity or hot weather, paint over the seams, or even nails or screws can be the culprit. Storm windows installed on the exterior of sash windows can help stabilize temperatures and also reduce inefficiency.

If the sash windows are stuck and you need to free them up, this how-to will walk you through the process.

Step 1 - Perform a Visual Inspection

Both on the inside and outside of the window, perform a visual inspection for any obstructions. You need to first find the source of the sticking window so that you can fix it. It may be that nails or screws were set into the frame of the window to prevent it from opening. If this is the case, they may have been painted over. The other likely causes of stuck sash windows are painted-over seams and swollen frames.

Step 2 - Remove Obstructions

If you find nails or screws hidden beneath paint, use a hammer or crowbar to pry out the nails. Use the power drill on reverse to remove the screws. They may be set in there tightly, so keep a firm hand while being careful not to damage the glass or the wood.

Step 3 - Clear Out the Seams

If the seams between the window frame and the sash have been painted over, take your utility knife and run it through the seams entirely around the window. Doing this should separate the paint and free up the window so you can open it. After running the knife along the slit, tap the sash (the wooden part) lightly with a rubber mallet to help loosen it further.

Step 4 - Pry the Window Open

If you followed the previous steps but the window still will not open, try prying it. Place a small block of wood on the sill. Using the block as a leverage point, insert the flat edge of the crowbar in between the sill and the sash. Apply downward force on the bar. The block of wood will help to safeguard the sill. Be careful not to go too fast or else you could slip and crack or break the glass.

Step 5 - Wait for Cool Weather

If none of these steps work, the wood of the sash may have swollen to an extreme point. Wood contracts in the cold. You might wait until a cooler evening before trying again to pry the window open.

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