I had transplanted a 90degree curved staircase out of an old victorian into a remodeling project home. At the time I had left 8 inches from plywood subfloor to top of 1rst tread allowing for about a half inch space for flooring to match the rest of the 7 1/2 inch steps. It’s done and secure. Don’t want to move it.
Now I’m thinking of changing the flooring to some 1 or 1 1/4 inch thick by 6 or 8″ oak randoms that I came across still roughcut to be planed down to desired thickness.
My question is how much tolerance one can be permitted to alter that height of the first step from the rest before it would become a safety hazard.
Could I have a 7 inch rise on the first and 7 1/2 on the rest?
Is that too much but 7 1/4 inch for the first step wouldn’t be noticeable?
Seems planing down to a 3/4 inch flooring thickness would be the minimum one would want to go. Thanks
Replies
Code in MA says they can't vary more than 3/16". Don't know if it's a code issue or a comfort one. Even still, 1/4" is as much as I would go.
You'll find some useful stair code info here.
http://www.arcways.com/IRC2000a.pdf
Nice link Joe. Hadn't seen that one.
All:
Our NC code allows the botton riser to be lower. Personally, I think it is fine, and do not think it is a safty hazard. The rest of the risers have to be the same within 3/8".Matt
Our NC Code, IBC, says that the top and bottom riser of interior stairs can't be more than 3/4" taller than the smallest riser in the set. I always figured they could be 3/4" less, too, but I don't really see that in the book.
An inspector once told me that the variance was allowed because of changing floor coverings, exactly Rez's situation.
I'd put something on the floor that was what the flooring will be, put my phone on the floor, and walk down the stairs. If I didn't have to call 911 from a horizontal position, I'd lay that flooring. EliphIno!
You are right. I stand corrected. It is only on exterior stairs that the bottom riser can be smaller. Matt
It's a code issue for safety. People tend to trip if the diff in stairs is noticeable. Your feet get used to a certain height and prefer consistency throughout that staircase.