| The minimum stair
tread run for the inside radius of a circular set of stairs can't be
smaller than 6 inches. I did find one building code that requested
a 10 inch minimum, instead of 6 inches.
Always double check with your building department. Remember, this
measurement is from stair tread nosing to stair tread nosing, not from
the back of an individual stair tread, to the front of the same stair
tread nosing.
2000 International Building Code Book calls out for 11
inch minimum from the 12 inch inside radius, not 10 inches.
The minimum stair tread width for a set of circular stairs is going to
follow the minimum stair tread
building code, except for the fact that you will be measuring 12
inches from the inside of the circular stairway, to find your reference
point, to check the stair tread minimum.
Example: You're going to be building a set of
circular stairs for a private residence and when you measure 12 inches
from the inside radius of the circular stairway, you have a 9 1/2 inch
wide stair tread. This would be acceptable under most building codes,
but would not be allowed in some other buildings that would have high
occupancies or accessible to the public, where the minimum stair treads
depth is 11 inches.
Attention: Don't forget to check with your local
building department to verify any building codes on this website. This
information could be incorrect or outdated. Building codes are updated
regularly and to some building departments have different
interpretations for certain building codes.
|
