'C'
| Cavity Wall | - | Usual construction for external walls comprising an inner and outer leaf with a space between for insulation |
| Ceiling Joist | - | A wood or steel beam which carries the ceiling beneath it |
| Cistern | - | Tank for storing water - usually located in the attic |
| Cleat | - | cable fixing for phone wire, etc |
| Coping | - | Protective finish to the top of a wall |
| Corbelling | - | Successive projecting courses of brickwork |
| Cove or Cornice | - | Moulding around room at junction of wall and ceiling |