Sister Form

• A. A form used for interior walls only
• B. Similar to edge forms, they differ only when the contractor decides to cast panels side by side, separated with only a common form
• C. A type of bracing system for slabs
• D. A temporary facade system for aesthetics

Answer: (B)

Sister forms are a formwork approach used when tilt‑up panels are cast side by side and share a single boundary form between them. They’re like edge forms, but the setup is specifically to allow two adjacent panels to be formed with only one common form between them. This arrangement makes it possible to cast multiple panels efficiently, with aligned edges and a common boundary, rather than building entirely separate forms for each panel. It isn’t about interior walls, it’s not a bracing system, and it’s not for aesthetics; it’s a practical formwork strategy to enable adjacent-panel casting with a shared boundary.