How to Install a Door Threshold

A door threshold seals the gap between the bottom of the door and the floor, protects the flooring from wear, and creates a clean transition between two floor surfaces. Here's how to install one correctly.

What Is a Door Threshold?

A door threshold is a strip installed on the floor directly under the door. It bridges the gap between two floor surfaces (like hardwood and tile) and works with the door sweep to create a complete bottom seal.

Types of Door Thresholds

• Flat threshold: Low-profile strip for same-level floors; easiest to install
• Saddle threshold: Raised in the middle; bridges height differences between floors
• Transition strip: Covers the gap between two different flooring types
• Interlocking threshold: Works with a door sweep for a complete weathertight seal

What You'll Need

• Threshold strip
• Measuring tape
• Hacksaw or miter saw (to cut to width)
• Drill and screwdriver (for screw-down types)
• Adhesive (for self-adhesive types)

• Floor Transition Strip Self-Adhesive Threshold (3.3ft) — deep brown wood grain finish; fits laminate, carpet, tile, and hardwood transitions; 1/5" to 2/5" height range

Step-by-Step Installation

Step 1: Measure the Doorway Width

Measure the width of the doorway at floor level. Standard doorways are 30–36" wide. If the threshold is longer, mark and cut to size with a hacksaw or miter saw.

Step 2: Check the Floor Height Difference

Measure the height difference between the two floor surfaces. Choose a threshold profile that bridges this gap smoothly without creating a trip hazard. The maximum recommended height difference for a standard threshold is 1/2".

Step 3: Position the Threshold

Center the threshold under the door so it sits directly below the door bottom when closed. The threshold should be centered on the door frame width.

Step 4: Install the Threshold

For self-adhesive types: Clean the floor surface with rubbing alcohol, peel the backing, press firmly into position, and hold for 30 seconds. Allow 24 hours before heavy foot traffic.

For screw-down types: Mark screw hole positions, pre-drill pilot holes, and drive screws flush with the surface.

Step 5: Test with the Door

Close the door and check that it clears the threshold without dragging. There should be no more than 1/8" gap between the door bottom and the threshold top.

Pair With a Door Sweep for Complete Sealing

A threshold alone doesn't fully seal the bottom gap. Pair it with a door sweep for maximum draft, noise, and insect protection.

• GroTheory Door Bottom Sweep 2-Pack (39") — works with the threshold to create a complete bottom seal

ADA Compliance Note

For accessible doorways, thresholds must be no higher than 1/2" and must be beveled on both sides at a slope no greater than 1:2. Keep this in mind when selecting a threshold profile.