1930's Era Roof

[CSFlanagan]

I'm evaluating a roof system for a client to place two (2) new HVAC units. The units weigh 600 pounds each, and can be placed near the end of the joist bearing. Joists are spaced at 7 ft centers. I've used SJI to determine that the joists are "186" Open Web Longspan steel joists from Bethlehem Steel's 1938 catalog.

What I don't know is the decking system. It appears to be a concrete panel, framed in metal. Width is about 18". There aren't any opening in the roof where I can measure thickness or profile the roof system.

I'm hoping someone has seen this before and can point me to a source for dead load.

Thanks,
Scott

 

[bridgebuster]

Is it concrete or could it be a gypsum roof with a cement board form? You could try this link, it's a site with 1000's of old trade publications.

Link