Calculate the Number of Treads and Understand the Logic

What happens in this clip

The number of treads is calculated using the formula: Number of Treads = Number of Risers - 1. This rule is explained by a small illustrative diagram, demonstrating that the final 'tread' of the staircase is typically the floor slab of the upper level, and therefore not considered a separate, individual tread that needs to be constructed as part of the staircase run. Therefore, if there are 22 risers, the number of treads will be 22 - 1 = 21 treads.

Goal: Determine the quantity of treads and understand their relation to risers

What's used

Tools

• Marker
• Whiteboard

About the full video

This project provides a step-by-step guide on how to calculate the basic dimensions for designing a staircase. It covers assuming appropriate riser and tread dimensions, determining the number of steps and treads, understanding staircase width guidelines, and calculating the total horizontal distance (run). The video emphasizes practical units (feet) for construction site applications.

Step 4 of 6: Determine Number of Treads (Steps)

For any staircase, the number of horizontal treads (the surfaces you step on) will always be one less than the number of vertical risers. If you determined you need 13 risers, you will need 12 treads.

Open this step in the guide

Every video in How to Measure Stair Rise and Run

1. Step 1: Determine Total Rise

   • 0:04–0:30 Measure Total Rise
   • 2:54–4:34 Determine the Total Rise
   • 0:54–1:25 Calculate Final Total Rise

2. Step 2: Calculate Ideal Riser Height

   • 0:29–1:07 Calculate Rise and Run
   • 4:32–5:10 Calculate Individual Riser Height
   • 0:28–1:03 Calculate Approximate Number of Risers

3. Step 3: Determine Actual Riser Height

   • 4:32–5:10 Calculate Individual Riser Height
   • 1:03–1:44 Calculate Riser Height (Option 1)
   • 0:28–1:03 Calculate Approximate Number of Risers

4. Step 4: Determine Number of Treads (Steps)

   • 0:54–1:13 Determine Number of Treads
   • 3:54–5:04 Calculate the Number of Treads and Understand the Logic (this video)
   • 8:59–9:54 Calculate Number of Risers and Treads

5. Step 5: Measure Total Run

   • 1:31–2:57 Calculate Unit Run and Total Run
   • 1:13–1:29 Calculate Total Run
   • 9:54–10:28 Determine Tread Run and Total Run

6. Step 6: Calculate Actual Tread Run

   • 0:29–1:07 Calculate Rise and Run
   • 1:31–2:57 Calculate Unit Run and Total Run
   • 10:55–11:31 Calculate Overall Run (Treads)