Expert: Dave Johnson - 11/23/2007

Question
QUESTION: need to build steps from first floor to basement.will have to b alternate stair design.the existing opening is below stairs from first floor 2 second floor.only available opening as basement clearance is 77" .total run is 25",total rise 51" available width 24"How do i determine angle of staircase .How do i build stringer eg. i need u to tell me unit rise ,unit run etc. since angle will be steep(assuming u can figure based on the limited info)i cant figure where i am to have each tread attached to figure how to cut the stringer

ANSWER: Hi James,
This is going to take some correspondence, but I think we can get thru it.
First the measurements: when you say total rise do you mean basement floor to 1st floor? total run seems short...
sound like you'll be using more like a ladder type. width not important.
let me know and we'll work on it...
Dave

---------- FOLLOW-UP ----------

QUESTION: yes basement floor to 1st floor is really 84" but was to make turn because head space for clearing is issue therefore thought L shape for landing which makes the total rise less i thought to account for turn. run is issue total is 49" ladder not solution nor spiral.

Answer
O.K. If what I think is true, you need a rise of 8.4"
That would give you 9 steps and then onto the floor.(actually 10 steps).
You would have 3 steps, then a "landing" of 24" x 24" that will have 2 pie shaped steps radiating from the inside corner of landing.
Then you will have 4 more treads to the first floor.
I would make the treads all 6" except for the landing.
Using a framing square, align the outside of it along the edge of your stringer using 8.4 on one side and 6" on the other...mark along the edge and repeat for as many steps as you need.
(SURE WISH THERE WAS A WAY TO DRAW A DIAGRAM FOR YOU...)
Please mail me again for anything you want.....
Dave