Sandwich panel

• A. A panel that adds an insulation layer and a non-structural exterior concrete wythe to the standard structural concrete layer
• B. A panel with no insulation
• C. A panel used for interior partitions only
• D. A panel for roofing systems

Answer: (A)

Sandwich panels in tilt-up construction are built as a composite with two concrete wythes and an insulating layer between them. The inner wythe is structural, carrying the loads of the wall, while the outer wythe provides a weatherproof, non-structural exterior finish. The insulation between the wythes gives the wall thermal resistance, improving energy efficiency and reducing heat transfer, often enabling faster on-site construction since much of the wall can be manufactured off-site.

The described option matches this concept: you end up with insulation between the structural inner layer and an exterior non-structural concrete skin. That combination is exactly what makes a panel a true sandwich panel—structural core plus an insulated, weatherproof exterior finish.

The other options don’t fit because a panel with no insulation lacks the essential thermal core; a panel used only for interior partitions isn’t providing an exterior skin or a structural, insulated assembly; and a panel intended for roofing systems describes a different application rather than a wall sandwich panel.