These are the two finishing stages of a construction project:

• Shell construction (obra gris): the unfinished structure. Concrete walls, floors, and ceilings, plus basic installations. The space exists, but it cannot be occupied yet.
• Finish-out (obra blanca): everything that makes it livable. Tiling, paint, bathrooms, kitchens, carpentry, lighting, and final finishes.

A project "completed to shell" and one "completed to finish-out" are at very different stages: only the second can receive guests or tenants.

Example: Phase 2 of Circular Houses reached 100% in July 2026: shell, finish-out, installations, finishes, and furnishing. In other words, ready to operate, not just built.