subceiling

/ˈsʌbˌsilɪŋ/
noun
  1. A secondary ceiling installed below the main ceiling, often for insulation, soundproofing, or decoration.
    • They added a subceiling in the basement to improve energy efficiency.
    • The old building had a subceiling that hid the original ornate plasterwork.
    • The contractor installed a subceiling to reduce noise from the floor above.
Antonyms