Which statement about form liner sealing is correct?

• A. To prevent concrete leakage during the pour, form liners must be properly sealed to the slab or form edge.
• B. They must be sealed only after the pour
• C. Sealing is optional if bond breaker is used
• D. Sealing can be replaced with painting

Answer: (C)

Form liner sealing is about preventing concrete from leaking through joints between the liner and the surrounding slab or form edge during the pour. When a bond breaker is applied to the liner, it creates a barrier at the interface and can reduce the tendency for concrete to intrude into joints, which in some practice guidelines leads to sealing being optional. That’s why the statement that sealing is optional if bond breaker is used is considered the best match to the scenario described.

Sealing ahead of the pour is typically advised to stop leakage, but the option here implies sealing isn’t always required due to the presence of the bond breaker. Painting cannot substitute for a proper seal, and sealing after the pour misses the purpose of preventing leakage during placement.