How to Fix a Door That Has a Gap at the Top

A gap at the top of a door lets in noise, light, drafts, and insects. It also usually signals a door alignment problem that will get worse over time. Here's how to diagnose and fix it.

Why Is There a Gap at the Top of My Door?

• Sagging door: Loose hinges have let the door drop, creating a gap at the top latch corner
• Door was trimmed too much: The top was cut down excessively
• Frame has racked: The door frame has shifted out of square, creating an uneven gap
• Door has warped: The door has twisted so the top corner pulls away from the frame
• Weatherstripping worn: The top seal has compressed or fallen off

Step 1: Check Hinge Tightness

A gap at the top latch corner almost always means the bottom hinge is loose. Tighten all hinge screws, especially the bottom hinge. Use 3" screws that reach the wall stud for maximum holding power. Test the door — this often closes the gap completely.

Step 2: Add Hinge Shims to Adjust Door Position

If the door hangs too low even with tight hinges, add a shim behind the bottom hinge to raise the latch-side corner, or behind the top hinge to lower it.

• Door Hinge Shims 10-Pack (0.040") — precise thickness for fine-tuning door position

Step 3: Add Weatherstripping to the Top Frame

If the gap is consistent across the full top edge (not just one corner), the door was trimmed too much or the frame has shifted. Add weatherstripping to the top of the door frame to seal the gap.

• Foam Weather Stripping Seal Tape 16ft (1/2" x 1/4") — self-adhesive, high-density foam, easy to apply to door frame

Step 4: Check Frame Squareness

Use a carpenter's square to check if the frame is still square. A racked frame creates a diagonal gap — large at one corner, small at the other. This requires shimming the frame or professional repair.

• Mr. Pen Carpenter's Square 8×12" — quickly verify frame squareness

Step 5: Fix a Warped Door

A warped door that twists away from the frame at the top corner is harder to fix. Options include:

• Add a third hinge in the middle to pull the door flat
• Apply weight to the door overnight to flatten a mild warp
• Replace the door if the warp is severe

Step 6: Replace Worn Top Weatherstripping

If the door fits correctly but the top seal is worn or missing, replace the weatherstripping on the door stop.

• Foam Weather Stripping Seal Tape 16ft — apply to the door stop where the door contacts the frame

Quick Diagnosis

• Gap at top latch corner only → tighten bottom hinge
• Gap across full top edge → door trimmed too much, add weatherstripping
• Diagonal gap (large one corner, small other) → frame racked, needs shimming
• Top corner pulls away when closed → warped door, add middle hinge