Help Identifying old roof deck 3

[KingKongdoor]

An architect sent me the pictures below, they are wanting to construct a small light framed dog house type structure on to an existing building to add some curb appeal. There is a mod bit flat roof on the other side. Age of building is not known, but appears to be around 60 to 70 years old. I"m headed to the building tomorrow to core the deck, but it is a panel I have not seen before and was hoping one you guys have.

 

[r13]

It looks like concrete deck to me - no seams, and no color of metal deck under the peeling paint. I don't know the darker stripes though.

 

[jdcollins]

That looks like a gypsum bulb tee roof.

 

[JedClampett]

If it's Poured Gypsum, here's a design and installation guide. It's from 1973, so it's very fresh.
It was big 50 or so years ago, than it fell out of style. One disadvantage it had was that if it got wet, it kind of dissolved.

A roof....

that gets wet...

dissolves.

Where's the flaw in that?