Interior work 8 sqft exterior work structural alterations category 2: install replace 2x floor joist @ 16" on center on 1st and 2nd floor. New steps 7 1 2" rise 12" tread new stringers. Replace roofing framing 2x8 @ 24" o. C. New roofing. Insulation on walls r21 insulation under roof r49 replace 8 int. Doors same size and location. Replace 12 windows drywall on wall and ceilings same size and location new flooring kitchen cabinets and replace front and rear doors as per code