I will be starting my basement renovation and need to install an indoor stairway, (currently I have to go through the garage). I will cut the original opening in a current closet space and need to know: How large an opening do I need? (8ft to basement) Can I save space (length) if I turn the stairs? Are the stringers I see at home improvment places the same used indoors? (pressure treated/needed) Although I am going through in a closet do I still need to "beef" up around, in case the out side walls are load bearing? THNX!