Many current codes frown on risers over 7". IIRC current IBC is 7
3/8". I try to come as close to 7 rise / 11 tread as possible.
This makes a combined riser+tread dimension of 18 or a 2R+tread of
25. There is no limitation of number of continuous stairs of
which I am aware. The number is most often determined by
dimensions and head clearance issues. The bigger issue, in my
professional opinion, is keeping stair noses in plane and avoiding
odd gaited risers. IBC speaks to this and limits variations in
any run of stairs to 1/4" or so. As has been mentioned here
before, a slight variation at top or bottom is not as accident
causing as anything mid run.

PRO:The lower the rise, the easier the climb.
CON: More steps, more total run distance.

(top posted for your convenience)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Keep the whole world singing . . . .
DanG (remove the sevens)




"scobiewan" wrote in message
oups.com...
Hi all,

A little background:

We're redoing the stairs in our 1865 house. They were
replaced in the 1920s or so and we're trying to put
them back more to their original configuration. There
are some walnut stair parts from the original stairs
in the attic and we plan on reusing as much of them as
possible.

We had an architect involved with some other aspects of
our renovation, and she also designed the new stair
layout for us.

The total rise between floors is 128". She designed a
staircase with 17 risers for a unit rise of 7.53". She
also specified a unit run of 11".

As I undersand it, this may or may not be code, but
definitely violates a couple of the guide formulas
that are commonly used (i.e. 2*rise + run = 24"-25").

I'm also reading that the rise should really be kept
at or below 7" and that you should only violate that
if you have space constraints or something.

So I was thinking of adding an extra stair (unit rise
would be 7.11") and making the unit run 10.5" (with +1"
bullnose). This would fall within the formula.

One other thing is that it's a straight stair. Is 18
steps too long to go up without a landing somewhere?

Does anyone have any experience with these issues that
might have some insight for us? We want the stairs not
to feel too steep. But we really want them to feel as
comfortable as possible.

Thank you very much in advance!
Dan