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Presentation 37:
STAIRWELL LENGTH AND HEADROOM
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Stairwell Lengthand Headroom
• A stairwell is the opening in a floor through which stairs are used.
• Its length depends on the unit rise and unit run of the stairs.
• Sufficient headroom must be maintained along the entire stair.
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Stairwell Lengthand Headroom
Stairwell length
Hea
droo
mUnit Rise
Unit Run
• Headroom must be more than 6′- 8″ (80″).
• The stairwell length is adjusted to maintain headroom.
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Stairwell Length
• Gentle stairs need a longer stairwell length to allow for the headroom.
Stairwell length
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Stairwell Length
Stairwell length• How many unit runs under the opening?
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Stairwell Length
Stairwell length• How many unit runs under the opening?
• This number depends on the number of rises under the opening.
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Headroom
• Number of rises is related to the desired headroom.
Hea
droo
m
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Headroom
• Number of rises is related to the desired headroom.
Upper Construction
Hea
droo
m• Note where the headroom is measured to on top.
• Upper construction must be included with the headroom.
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Stairwell Length Procedure
1. Add desired headroom to upper construction measurement.
2. Divide this number by the unit rise and round up. (This is # of unit runs).
3. Multiply this number by unit run.
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Stairwell Length Calculation
• Determine stairwell length if: 12 ½″
10 ½″
7 ½″80
″
Unit rise = 7 ½″
Unit run = 10 ½″
Headroom = 80″
Upper const. = 12 ½″
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Calculation
• Add headroom to upper construction.80 + 12 ½″ = 92 ½″ total clearance
• Divide by unit rise and round up.
92 ½″ ÷ 7 ½″ = 12.333 → 13 rises
• Multiply by unit run.
13 x 10 ½″ = 136 ½″ Stairwell Length.
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Stairwell Length Calculation
• Stairwell length should be 136 ½″.
7 ½″
10 ½″
12 ½″
80″
136 ½″
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Conclusions
• Headroom is typically more than 80″.
• Stairwell length is determined from headroom, upper construction thickness, unit rise, and unit run.