NC-Dek is a 3" deep, cellular structural roof deck unit that provides a support surface for various types of roofing materials. The liner panel with Dek-Knek″ Sidelap Attachment System provides a finished underside ceiling with self-aligning sidelaps and concealed fasteners. NCA-Dek is a 3" deep, cellular, acoustical structural roof deck unit with a perforated liner panel that provides a noise reduction coefficient (NRC) value of 0.95 with rigid insulation. Fiberglass insulation batts are installed in the deck cells at the factory under controlled conditions.