Some stairways won't
require the use of, stair risers. However, if your stairway is going to
require risers, you can use plywood, oriented strand board and even
construction standard lumber.
Now pay attention here, this could be another problem that you're not familiar with. If you're building a stairway that's going to do be used as an emergency building exit, it might require special stair treads and risers.
I built a heavy-duty stairway that required 2 x 6 stair risers, just in case a fire ever started underneath the stairway. Remember, in a situation like this, your local building department and structural engineer, could become your best friend.
However, if you're planning on building a light duty stairway, your choices for stair riser building materials, are practically unlimited.
Stair Building TipYour stair riser can provide additional structural support, for your stair treads, if positioned properly. Make sure that the risers are always held up tight against the bottom, of the stair tread.
It's important to cut your stair treads and risers as Straight as possible. Any gaps between the top of the riser and the bottom of the stair tread, could cause stair tread fluctuation, otherwise known as structural damage and stair squeaks.