Materials used to cover or encase walls, ceilings and roofs of framed structures (examples include gypsum, OSB, and plywood) are called ...

• A. Insulation
• B. Framing
• C. Sheathing
• D. Finishing

Answer: (C)

Sheathing is the layer that covers the framing on walls, ceilings, and roofs, creating a solid surface for attaching the final finishes and giving the structure stiffness. Gypsum, OSB, and plywood are common sheathing materials. Gypsum boards are typical interior finishing panels, while OSB and plywood panels form the exterior or roof sheathing that nails to the framing and provides a base for siding or roofing while helping resist loads and transfer forces. This is different from insulation, which lives in cavities to reduce heat flow; framing, which is the structural skeleton; and finishing, which is the final surface treatment applied after the sheathing.