Common Interior Door Threshold Questions:

Interior Door Thresholds – Overview & Guide

Why Use Interior Door Thresholds?

• Floor transitions: Used when connecting rooms with different flooring materials.

• Height differences: Helps bridge uneven floors (e.g., 1/4", 1/2", or larger differences like 3/4" hardwood to thinner flooring).

• Gap coverage: Covers gaps between rooms, especially in renovations or additions where flooring may be missing.

• Wide coverage options:

  • Standard widths up to 6 1/2"

  • Two-piece thresholds up to 13" wide (requires a filled, even subfloor)

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Can They Be Used as a Thermal Break?

• Doors typically have a 1/2"–3/4" gap underneath.

• An ADA threshold (1/2" height) can help reduce this gap and improve insulation.

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Types of Hardwood Interior Thresholds

1. Small Thresholds

• Designed for minor height differences between floors

2. Wider Overlap Thresholds

• Extend further onto one flooring surface for better coverage

3. Flat Thresholds (Tapered Edges)

• Available in:

  • 1/2" height (ADA compliant) – wheelchair accessible

  • 3/4" height

• Widths: 3 1/2" to 6 1/2", or up to 13" (2-piece)

• Used for:

  • Covering gaps

  • Accessibility transitions

4. Tapered Thresholds

• Thickness:

  • Up to 3/4" at highest point

  • Tapers to 1/4" or less

• Widths up to 6 1/2"

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Installation Methods

⚠️ Important: Do NOT simply nail directly into the floor

• Can crack the threshold if done improperly

Proper Nailing Method

1. Ensure a solid, flat base

2. Drill pilot holes

3. Use finishing nails

4. Countersink nails with a punch

5. Fill holes after finishing

Adhesive Method (Recommended for Concrete)

• Use construction adhesive

• Requires a stable, level surface

• Avoids drilling large holes for fasteners

Key Installation Tip

• Always install over a solid, even base

• Thin areas (as little as 1/4") can crack under pressure if unsupported

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Finishing Requirements

• Thresholds are shipped unfinished

• Must be stained or painted before installation

• Finish all sides to prevent:

  • Moisture absorption

  • Warping

• Especially important for:

  • Concrete installations

  • Wider/longer thresholds

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Options for Floors with Different Heights

Option 1: Butt-Up Transition

• Threshold meets the higher floor directly

• Creates a smoother, safer transition (reduces tripping risk)

• Works well for 1/2"–3/4" differences

Option 2: Overlap Transition

• Covers seam between floors

• Gradually transitions between heights

• Ideal for 1/4"–1/2" differences