Probably been asked but if any pros can advise I would appreciate it.
I have a year 2000 built house with those TJI I beams 16" on center (with a few closer than that) which I can access from the unfinished basement. And they are glued down as well as nailed (I can see two nails that missed)
The room in question is 12' by 15' so pretty small.
I want to run the hardwood parallel to the joists. I haven't yet pulled the old carpet but I would prefer not to add more subfloor due to a major transition from one room to the next and I don't want to make it even taller.
The flooring feels really solid. With these newer home construction I beams is running parallel that big of a deal?

(BTW-this is not our forever home so while I want to do it with quality I don't want to sink a ton of money in the house)

well now I see the sticky above. duh

that being said, some more info-
16" on center with a 14.5" unsupported span. looks like from a hole i drilled to run wires through a crawl space it's 3/4" ply.

I'm having a hard time thinking i can't run it parallel as the floor seems pretty stout.

Have you laid a six ft level across the floor to check for dips? Either that or a string under a bucket?
As the owner you can do anything you want, you just don't want to see dips between the joists. 16" on center is pretty tight.