What is this ceiling material made of?

[Randall Clark]

This structure sat over a pool patio that was likely built in the 70's. The ceiling is something I've seen before but can't recall where and what this is made of. Any idea? Ignore the water stains.

[Jerry Peck]

Tectum-The Noise Control Solution-Structural Acoustic Roof Deck (http://www.tectum.com/roofdeck.htm)

Tectum.

[Randall Clark]

Tectum-The Noise Control Solution-Structural Acoustic Roof Deck (http://www.tectum.com/roofdeck.htm)

Tectum.


Thanks!