How to Fix a Window That Won't Close

A window that won't close fully lets in cold air, rain, insects, and noise. It's also a security risk. Here's how to find the cause and fix it properly.

Why Won't My Window Close?

• Warped or swollen sash: The window sash has expanded or twisted and no longer fits the frame
• Broken sash balance: The counterweight or spring balance has failed, preventing the sash from staying down
• Debris in track: Dirt or buildup is blocking the sash from closing fully
• Bent or damaged frame: The frame has shifted or been damaged
• Broken hardware: The crank, operator, or latch mechanism is faulty
• Paint buildup: Layers of paint have made the sash too thick for the frame

Step 1: Clean the Tracks

Vacuum and scrub the window tracks thoroughly. Even small amounts of debris can prevent a window from closing fully. After cleaning, lubricate with silicone spray.

• DuPont Silicone Lubricant with Teflon 10oz — spray into tracks after cleaning for smooth operation

Step 2: Check for Warping or Swelling

Close the window as far as it will go and look for where it's binding. Mark the contact point. If the sash is swollen, sand the binding edge lightly on a dry day.

• Sanding Sponge 8-Pack (60–220 grit) — for sanding window sash edges by hand
• Amazon Basics Hand Planer No.4 — for removing more material from a significantly swollen sash

Step 3: Check the Frame for Damage

Inspect the frame for bowing, cracks, or impact damage. A bowed frame narrows the opening and prevents the sash from closing. Minor bowing can sometimes be corrected by adjusting the window stops.

Step 4: Fix Paint Buildup

If multiple paint layers have made the sash too thick, strip the paint from the sash edges and repaint with a single thin coat. This is common in older homes that have been repainted many times.

Step 5: Repair or Replace the Sash Balance

For double-hung windows, a broken sash balance (spring or cord type) can prevent the lower sash from staying closed. Replacement balances are available by window brand and size at hardware stores.

Step 6: Adjust the Window Stops

Window stops are the thin strips of wood that guide the sash. If they're too tight, the sash can't close. Remove the stop, move it out slightly, and re-nail.

Step 7: Seal After Any Sanding

Always prime and paint any sanded window edges. Bare wood absorbs moisture and will swell again, causing the same problem to return.

Quick Diagnosis

• Won't close at all → check tracks for debris first
• Closes partway then stops → swelling or paint buildup at that point
• Closes but won't latch → latch or lock hardware issue
• Closes but won't stay closed → broken sash balance