Type of sheathing?

[Kristi Silber]

This is a photo under an eave. 1955 house, flat roof. I'm not sure if this is actual roof decking or not. From interior photos of the house I found on the internet, it appears that the same stuff is used uncovered as ceiling inside the house. I'm not familiar with it. Tried to find it on the 'net, to no avail. What is it?

[Jerry Peck]

Kristi,


I forgot to include this with that photo I sent you ;) : Tectum is what that is called.

Long span planks, roof deck tile and concealed tee acoustical decks (http://tectum.com/tectumi.htm)

[Markus Keller]

Looks like standard wood particle strand board. Was used a lot more. Don't see it used as much more these days around here at least. I think OSB overtook it as a cheaper plywood alternative. Does not like water. Typically non-compliant for interior exposed use due to lack of fire rating. Could be fire protected but no way to tell from the pic.
Just my guess.

[Kristi Silber]

Ah, Tectum, that's it! Aspen wood fibers bonded with a cement binder. Interesting! I figured that wouldn't take long.

Thanks for the pic, Jerry ;)