Maximum height for a single step

[David Jensen]

I have a situation in my remodeling project where the floor elevation needs to change about 8 inches. My question is this: at what point does a single step from one platform to another (in other words you are stepping up or down onto a large area, not a "step") become awkward, uncomfortable, unsafe, out of code etc. I imagine that it is somewhere between 7.5 and 9 inches, but I'm not sure.

Thanks in advance for your input.

David Jensen

[Arin]

8" max. riser height no more than 3/16" difference from one riser to the next.

[Dan G]

I need to double check, but I think the newest UBC calls out a maximum of 7 1/4".

8" is right on the verge tall, sure nothing over it.

[JTM]

The American National Standards Institute (ANSI) recommends 7" maximum rise with

11" minimum tread. Of course local codes will govern. Values outside this may be classified as stair ladders which can exceed the recommended values for a stairway.

A single step probably falls under a separate category not governed by stair design. I would be guided by local building codes. Why not create a shallow ramp in front of the rise to get the rise into the stair range. If it is feathered in it would be hard to spot. Or just make it a two step affair.

Stadium design often (usually) violates these recommendations because of the incompatible requirements of shoehorning as many people as possible in a very steep configuration. (either the tread must be too narrow or the rise must be too high or both.

Regards,

John

[Ann G]

Even without my code books home to confirm, I doubt the stair code has changed from the last '01 U.B.C version to the newest '03 I.B.C.

To absolutely check the latest you'd check the '03 I.B.C - "International Building Code", since BOCA, ICBO and SBCCI recently joined forces to form the International Code Council and has produced the "I-Codes". ICBO being the former code model group who formerly provided the U.B.C. - Uniform Building Code