mark wrote:
Greetings All,
I am wondering if there is a short set of rules for residential stair
tread heights. In a nutshell,
we had a second floor added a couple of years back. The stairs are
just site-built plain old utility grade 2x treads that are held by
nails and construction adhesive. The flooring at both the bottom of
said stairs and top are now finished, so I would like to pretty up
the stairway. I know there are certain dimensions to adhere to
pertaining to tread height, depth and the max variation from tread to
tread. Is this something covered by a national code, or does it vary
by municipality? An architect (student) told me allowable tread
height is from 7" to 7 1/2" and no more than 3/32" variation in tread
height over the run of stairs. I plan on having to remove the 2x treads
and hope to use the existing
stringers. I have a thickness planer, so I can pretty much make any
thickness product necessary to conform to code. Thanks to all who are
able to help, Mark

The big reason for no variation in tread height is muscular expectation of
where the next step will be. If your body doesn't find the step where it
expects, there's an excellent chance of falling.