Is it possible that my ceiling does not have joists?

It may be a dropped ceiling. The actual ceiling above it will have the joists.

The only thing that i can come up with is that when it is a ceiling which is made of plaster boards, usually there are joists every 60 cm (in the Netherlands that is), starting from the wall.
That could be worth a try?

Assuming you can locate a joist:
If you need to firmly attach a ceiling hook into a joist several inches above the ceiling surface, consider using a “hanger bolt”, which is typically a ¼ or 5/16” bolt threaded at both ends. One end has coarse threads for wood & the other end has fine machine threads that will accept standard hex nuts or hex joiners, the latter for attaching (if necessary) a threaded extension rod of any length. The rod can simply poke down through the ceiling to accept a mating hook.

The hanger bolt can be screwed into the joist by attaching a pair of nuts and tightening them against each other, then applying torque to the outer nut to rotate the whole assembly into the wood (drill a pilot hole first). Make sense?

@gasman that makes sense, yeah. Is there a way to locate the joists without tearing the whole ceiling down though?

You said, “I ripped a hole in the ceiling to take a look around and saw that there was some wooden support about 2.5 inches above…” Are you describing a horizontal beam / joist or just the bottom of the floor above?

In the U.S. floor joists are 16 inches apart (though 12” or 24” is possible)—that’s a very old standard, so chances are when you find one joist you’ve found them all. You might have to enlarge the ceiling hole to allow sticking your head into the space above the ceiling with a flashlight & looking 360 degrees around.

Stud finders aren’t always that reliable if the framing is non-standard, or if (like my house) the walls & ceiling use plaster & lath instead of drywall. You might need to buy a super-long drill bit to probe for solid wood by drilling a series of holes. It helps to at least know which direction the joists run. If the floor above is hardwood boards, they’ll be perpendicular.

I actually made that hole in another room. I haven’t done it in this room yet. the space between the ceiling and the possible joist is only a few inches, so I couldn’t really look to other space in any case.

There’s no floor above me, but I’ll look into buying an extra long drill bit.

thanks!

Also before you start drilling up vertically through the ceiling, beware of electrical cables !