normally have 3 stringers, which are the long pieces of wood that
bear the weight from the stair tread. The stringers are on both
ends and a single one in the middle.
the load to the both the upper and lower floors, the stringers have
a stair step pattern cut into them, so that the stair tread and
riser can be fastened.
can be fastened to the floor by using a joist hanger or metal bracket.