This type of stair saves lots of space and can have standard rise and run dimensions to meet code. However, it is quite steep and a bit scary to go down head first (most people turn around, like you would on a ladder). Some building codes will allow this type of stair into lofts of 250 sf or smaller. Here are some suggestions about how to build this type of design. It is sometimes called a Jefferson stair as Thomas Jefferson was an early promoter of the space efficient design.

I hope this gives you some useful ideas. John Raabe, For a better printing PDF file click HERE

I think I would add a non-slip surface material to the step portion of the tread.

Adjust the riser height to the space between floors. For a 9’ floor to floor height there would be 14 risers of 7.714”. Start with this and adjust the angle of the carriage from there.