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

A gap at the bottom of a door lets in cold air, noise, light, insects, and dust. It also wastes energy and raises heating and cooling bills. Here's how to seal it properly.

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

• Standard clearance: Interior doors are designed with 3/8"–1/2" clearance for airflow and carpet clearance
• Door was trimmed: The door was cut down and the gap is now too large
• New flooring removed: Old thick flooring was replaced with thinner material
• Door has sagged: Loose hinges have let the door drop, creating a gap at the top and a drag at the bottom — or vice versa
• Exterior door gap: The threshold seal has worn out

Solution 1: Install a Door Sweep (Best for Most Doors)

A door sweep attaches to the bottom of the door and seals the gap automatically. It's the fastest and most effective solution for both interior and exterior doors.

• GroTheory Door Bottom Sweep 2-Pack (39") — fits exterior and interior doors, blocks cold air, noise, and insects; easy screw-on installation

Installation: Cut to width if needed, align with the door bottom, and screw into place. The sweep should lightly brush the floor when the door closes.

Solution 2: Install a Door Threshold

For exterior doors, a threshold strip seals the gap between the door bottom and the floor. It also protects the floor from wear.

• Floor Transition Strip Self-Adhesive Threshold (3.3ft) — deep brown wood grain, fits laminate, carpet, and tile transitions

Solution 3: Add Weatherstripping to the Door Frame

If the gap is between the door bottom and the threshold (not the floor), add foam weatherstripping to the threshold surface.

• Foam Weather Stripping Seal Tape 16ft (1/2" x 1/4") — high-density foam, self-adhesive, soundproofing and insulation

Solution 4: Fix Sagging Hinges

If the gap is uneven — larger on one side than the other — the door has sagged from loose hinges. Tighten all hinge screws and use longer 3" screws to reach the wall stud.

Solution 5: Adjust the Door Height

If the gap is too large across the full bottom (more than 1"), the door may need to be rehung higher, or a new door installed. This is a more involved repair but may be necessary for exterior doors with large gaps.

Choosing the Right Solution

• Gap under 1" on interior door → door sweep (normal, leave it or add sweep for noise/privacy)
• Gap over 1" on interior door → check hinge alignment, consider door sweep
• Exterior door gap → door sweep + threshold seal for best energy efficiency
• Uneven gap → fix hinge alignment first

Energy Savings Note

Sealing a 1/4" gap under an exterior door is equivalent to closing a 2.4 square inch hole in your wall. A door sweep pays for itself in energy savings within one heating season.