Understanding Tread Depth and Nosing

What happens in this clip

The video uses a 3D animated model of a staircase to demonstrate how tread depth is measured. Starting with a 9-inch tread, it shows that while the structural tread might be 9 inches, additional length can be gained through nosing (an overhang). The presenter references the '2024 International Building Code - 1011.5.2 Riser Height and Tread Depth' to emphasize that these dimensions are governed by regulations. Examples are shown where adding an inch makes it a 10-inch step, and adding an additional 1.5 inches results in an 11.5-inch step. A warning is displayed: 'Long Nosing Can Create Trip Hazards', indicating that excessive overhang can compromise safety.

Goal: This step illustrates how adding nosing to a stair tread can increase its effective length, referencing building codes and highlighting the difference between actual tread depth and the total step length with overhang.

About the full video

This video explains the reasons why stair treads cannot be indefinitely lengthened, especially in tight spaces, focusing on building code requirements for riser height and tread depth, and how nosing affects usability when ascending versus descending stairs.

Step 1 of 4: Measure Stair Tread Depth

Place a tape measure at the very front edge of the stair tread, ensuring it is flush with the nosing. Extend the tape measure straight back along the tread surface until it meets the riser (the vertical part of the step). Record this measurement as the tread depth.

Open this step in the guide

Every video in How to Measure Stair Tread Depth and Nosing Overhang

1. Step 1: Measure Stair Tread Depth

   • 0:54–1:39 Measure Stair Tread Depth
   • 0:57–1:16 Measure Treads and Mark Laminate
   • 0:24–0:56 Understanding Tread Depth and Nosing (this video)

2. Step 2: Measure Nosing Overhang

   • 0:55–1:13 Measure and Mark Tread and Nosing
   • 5:03–6:09 Determine Tread Overhang and Length
   • 0:28–1:15 Measure and Mark Nosing Length

3. Step 3: Measure Total Tread Depth (Including Nosing)

   • 0:57–1:16 Measure Treads and Mark Laminate
   • 0:54–1:39 Measure Stair Tread Depth
   • 0:31–1:01 Measure Riser Height and Tread Depth Consistency

4. Step 4: Record Measurements

   • 0:57–1:16 Measure Treads and Mark Laminate
   • 0:31–1:01 Measure Riser Height and Tread Depth Consistency
   • 0:55–1:13 Measure and Mark Tread and Nosing