In a style appropriate to the existing house, add a 16-by-25-foot room on a crawlspace foundation with vinyl siding and fiberglass shingle roof. Include drywall interior with fiberglass insulation, pre-finished hardwood floor, and 180 square feet of glazing including windows, atrium-style exterior doors, and two operable skylights. Tie into existing HVAC. Add electrical system to code, including 12 recessed ceiling lights.