Changing the tread size of a staircase in a building
Changing the tread size of a staircase in a building
(OP)
I am aware of the fact that changing the rise dimension of a staircase might cause accidents. So I did not change that. However, I changed one of the floors tread by 20mm. The entire building has 300mm steps except for one of the middle floors which has 280 mm steps. I would like to point out that every floor of the building has the same steps; except for one floor which has the 280mm ones. Are there any rules against it or would people notice it? Thanks.






RE: Changing the tread size of a staircase in a building
RE: Changing the tread size of a staircase in a building
Other details that you have not mentioned, such as the dimension of the rise, number of floors in the building, and which floor is different could make this issue more important. If it is not too late, suggest you keep all rises identical and all the runs identical.
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RE: Changing the tread size of a staircase in a building
Dave
Thaidavid
RE: Changing the tread size of a staircase in a building
Key words being "within any flight of stairs" I haven't found anything regarding successive flights of stairs (separated by landings).
Not sure if this is the case here but you can see the Run (Tread width). Can the human mind react quick enough to a
sudden, approximately 3/4" (20mm) difference in tread width to maintain a stride down the next, completely different set of stairs?
Somebody might have an answer but untill you find it I echo XR250,
PS. Here's a little food for thought.
https://www.youtube.com/watch?v=cji3Ih1GP0k
Looks like a riser height issue but entertaining just the same.
Doug
RE: Changing the tread size of a staircase in a building
RE: Changing the tread size of a staircase in a building
If you are cropping off an inch at the back of the stair tread due to some obstruction and the stair is not used for egress, I would ask an architect.
RE: Changing the tread size of a staircase in a building
It is not one "work line", it is two different stair flights.
I would agree with SRE and Ron in principle, but these stairs are not your ordinary egress stairs. 300 and 280 are both wider than "normal", and I think as long as the treads in each flight are correctly proportioned with the risers, the 20 mm difference in tread length would not be noticeable.
RE: Changing the tread size of a staircase in a building
I know I read a study where stair tread and rise were altered, but I don't know where to look to find it again. I think the study indicated that the key was variation from one step to the next; keeping it the same on an entire flight is best, but continuous increase or decrease is not insurmountable, as long as the variation is small. Human locomotion is adaptable as long as it's not too much change.
RE: Changing the tread size of a staircase in a building
RE: Changing the tread size of a staircase in a building
But for those in the rest of the world, none of us who use the IBC, does it address uniformity between separate flights? That section sounds like just a dimensional tolerance thing.
RE: Changing the tread size of a staircase in a building