Understand and Calculate Stair Angles
From How to Find the Angle of Your Stairs · Step 3 of 3 · Video by drdecks
Showing 0:00–0:35 of the source video. Watch the full video with every moment.
What happens in this clip
The video highlights the crucial importance of precisely calculating stair angles, identifying it as the most critical, challenging, and time-consuming phase in stair construction. It introduces a general formula for determining both the upper and bottom angles based on the main 'stair angle'. The stated formulas are: Upper Angle = Your stair angle + 2 degrees; Bottom Angle = (90 degrees - stair angle) + 2 degrees. The presenter illustrates this concept with a hand-drawn diagram of stairs, showing various angles (e.g., 16.5°, 33°, 28.5°) and calculations, explaining that once these core angles are correctly established, they can be consistently duplicated for every rise and run throughout the entire staircase. This approach ensures uniformity and simplifies the subsequent building process, allowing for efficient construction of symmetrical stairs regardless of the total number of steps.
Goal: Accurately determine the upper and bottom angles for stair construction using provided formulas and apply the principle of angle duplication for consistent results.
What's used
Tools
- Angle Finder/Protractor
- Framing square with pivot
- Calculator
- Online calculator
- subtraction).
- Paper
- Digital drawing tablet
- Cardboard
- Pen/Pencil
- Digital pen
- Ruler/Straightedge
- Measuring tape
About the full video
This video provides a conceptual guide to accurately calculating and understanding stair angles, emphasizing their critical role in stair construction. It presents a simple formula for determining the upper and bottom angles of stair stringers, ensuring consistency across all steps and simplifying the duplication process for a complete staircase.
What's said in this clip
The most important [music] part and the hardest part and the most time consuming part is making this piece right here. Once we got that figured out, then the [music] rest of this becomes a little bit easier and you're just duplicating your angles on [music] right and left. Now, the cool thing about this particular set of stairs, every single rise, every single run, they're exactly the same [music] on every staircase. So, even though there's different amounts of stairs, my angles should be able to be duplicated [music] for each set of stairs so that as long as I remember these angles or write them down, then I'll know that I'm in the right zone.
Automatically transcribed from the source video.
Step 3 of 3: Calculate the stair angle
With the total rise and total run values obtained, use the arctangent (or inverse tangent) function to calculate the angle of the staircase. The formula is: Angle = arctan(Total Rise / Total Run). You can use a scientific calculator or a spreadsheet program for this calculation. The result will be in degrees.
Every video in How to Find the Angle of Your Stairs
Step 1: Measure the total rise of the staircase
- 0:15–0:29 Measure Total Rise
- 2:54–4:34 Determine the Total Rise
- 0:01–0:28 Measure Total Vertical Rise
Step 2: Measure the total run of the staircase
- 2:54–4:47 Measure Straight Stairs
- 0:15–0:29 Measure Total Rise
- 2:06–3:02 Measure Total Run
Step 3: Calculate the stair angle
- 0:31–1:14 Retrieve Default Stair Parameters
- 0:00–0:35 Understand and Calculate Stair Angles (this video)
- 1:21–2:07 Determine Staircase Angle
How to Find the Angle of Your Stairs
This project outlines the process for accurately determining the angle of existing stairs, which is often needed for repairs, renovations, or when building new stairs to match existing ones. The process involves taking precise measurements of the stair's rise and run and then using trigonometry to calculate the angle.
Read the full guide Browse all guides
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