Steel joists and rafters?

[Danny P.]

Hey ya’ll, we just closed on our second flip today and I have a question about the construction. The house is a 1990 Habitat for Humanity build and when I poked my head up in the attic, I was surprised to see that the whole structure above the ceiling is steel construction. It looks really solid and the roof sheathing and everything else looks very clean and dry. It has a typical plywood sheathing and architectural shingle roof. Ceiling joists looked to be maybe 2x6 square tubing and then steel cross members going up to the roof rafters that looked like they were just unistrut. Just wondering if anyone else has run into this type of construction before, Habitat house or not.