Traditional
stairs require laying out and cutting multiple
stringers (one stringer for every 18-24"
of stair width) and then attaching and aligning
the stringers. Once the stringers are installed,
the risers and treads can be attached. The
treads must be glued to prevent squeaking.
This method of construction requires one of
the highest skill levels in the building industry.
If you make a mistake or slight miscalculation,
then you have to throw out the wood and build
the stringers again from scratch.