# Calculating Stair Run Length

• posted on February 21, 2004, 1:20 pm
I am trying to figure out given a 9 foot ceiling height on the first floor how long a staircase will be to the second floor using a standard rise/run. Basically I need to to see how long to make a hallway with stairs in it to the second floor. Thanks for your help. Tim
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
• posted on February 21, 2004, 3:06 pm
You should go to the library and get a good carpenter book.
The basic answer is that a comfortable stair has about 7" risers and 11" treads. There are other methods, such as 2 risers + 1 tread %". In your case divide 108" by 7" to find the number of risers. Code restricts height of risers, I believe it is currently 7 3/8" if your risers get larger than this, you need to add another step. Find the total number of treads and multiply by 11"
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Keep the whole world singing. . . . DanG

<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
• posted on February 21, 2004, 6:22 pm

Shouldn't this be find the total number of *risers* (not treads) and multiply by 11"? I'm no carpenter, but seems to me that you'd need to know how many risers you'd need first to know how many treads you'd need in order to multiply by 11 (and thusly be able to calculate how far the staircase will extend), no?
Or maybe I shoulda just learned my lesson from the ice dam and furnace working harder topics and shut up ...
Nah.
AJS
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
• posted on February 21, 2004, 6:27 pm
"AJScott" wrote in message

That's what Dan said. I believe you need another cup of Java this afternoon AJ! :o)
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
• posted on February 21, 2004, 8:42 pm

No, that's not. Dan said (generally) risers are 7" and treads are 11". He gave the math to calc the number of risers (108"/7"), but not how many treads would be needed according to that calc that in the end gives you the total length of the staircase. He simply said "find the number of treads and multiply by 11." Under that instruction, he didn;t give any calc on *how to find the number of treads*. Seeing that he said multiply 11 (instead of 7), I naturally assumed he meant to write riser instead of tread but got himself reversed while writing the post.
AJS
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
• posted on February 21, 2004, 8:59 pm
wrote:

need
the
afternoon
Maybe it didn't confuse me because I can build steps. Now, the 108/7 _will_ be the number of treads, depending if you want your first tread starting even with floor . You find the number of treads exactly like he said, depending how you want the first tread to fall. Then you multiply exactly how he said. You multiply the run (tread width) by rise, exactly what he said in answer to the OP's question of " I need to to see how long to make a hallway with stairs in it to the second floor."
Make that you need yet another cup of java.
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
• posted on February 21, 2004, 9:07 pm
"Gunner" wrote in message

_will_
a
width x the _#_ of risers which is found by 108/7
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
• posted on February 23, 2004, 3:17 pm

I wasn't confused the first time around, since I know that the number of risers you have will give you how many treads you'll have. I'm not *that* retarded. It was the wording of the very last sentence (Find the total number of treads and multiply by 11") that I raised an issue about. I thought the *way* he worded it *may* confuse people who don't know how to build stairs because he didn't make clear that the number of risers you get automatically provides you the number of treads with which to multiply by 11" or whatever depth you want your tread to be. He simply said "find the number of treads" without saying that you've already found it with the number of risers provided by the "divide by 7" calc.
You said it in your post here, but Dan didn't make this clear in his original post, IMO.
AJS
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
• posted on February 21, 2004, 6:45 pm
Oh AJScott...
Is there anything you *don't* know? =:-)
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
• posted on February 21, 2004, 8:46 pm
snipped-for-privacy@aol.com (HA HA Budys Here) wrote:

Plenty of things I don't know, but I'm not against being the retarded guy if something doesn't make sense to me. Asking stupid questions is pretty much the only way anyone learns anything.
AJS
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
• posted on February 22, 2004, 2:23 pm
I assumed . . . . . . .
A prudent person would make a sketch of the situation. I gave the correct method of determining the number of risers required.
Make a line on a piece of paper to indicate the floor at the bottom of the stair. Make another line to indicate the floor at the top of the stair. Make the sketch with the number of risers that were calculated. The number of treads does not necessarily equal the number of risers. It will be totally dependent on how you tie in the top and/or bottom.
From the sketch determine the number of treads that you will need to complete the stair as sketched. Multiply by 11" or whatever tread dimension you chose to use. If you are cutting the stringers you will need to do a lot more figuring. You will need to know tread depth, finish floor treatment at top and bottom. As an example, if you are looking at subloor dimensions before completing hard wood flooring, you will need to adequately consider this information in your calculations. Code will also require that you create an "even gaited stair" We have all stumbled on stairs with an odd ball riser at top or bottom.
Hope this made it more clear. I repeat, pictures are worth 100 words. Go to the library.
On a wild googlechase I found this:
http://www.vil.downers-grove.il.us/pdf_files/codesrvs/VODGIRC2000.pdf
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Keep the whole world singing. . . . DanG
wrote:

risers
of
to
multiply by

and
need to

you'd need

far the

furnace
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
• posted on February 23, 2004, 12:05 am
Another minor correction: After you figure the number of treads and determine the tread width, say 11 1/4", than multiply the number of treads by 10, not 11 1/4. This would be the run since there is a 1 1/4 overhang.
wrote:

<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
• posted on February 22, 2004, 1:48 am

Just a minor correction (I hope). It has been years since I did it but doesn't the number of treads come to 1 less than the number of risers? Not sure now, and too lazy to look it up.
Harry K
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
• posted on February 21, 2004, 8:24 pm
As state below, dived the height (rise) by 7 this will give you the number of risers. (don't use 108, this is to the bottom of the ceiling you need to the top of the 2nd floor). Depending on how you build the stairs you will have either the same number of treads (runs) or one less.

<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
• posted on March 4, 2004, 1:34 pm
Fine Home Building has had a couple of very good articles on stair design in the past 10 years. You might try to search their web site.
RB
Nelson wrote: