Finishes, systems, framing top costs Interior finishes (e.g., cabinets, drywall, flooring): 24.1% Major system rough-ins (e.g. electrical, HVAC, plumbing): 19.2% Framing: 16.6% Exterior finishes (e.g., roofing, windows): 13.4% Foundations: 10.5% Site work (e.g., architecture, building/permit/impact fees): 7.6%