Can 2x4s holding up ceiling drywall support a ceiling fan using a brace and box?

Question

I went to remove a plastic ceiling box where a light fixture was in our home in order to install a ceiling fan brace and box, only to realize that there's actually another old popcorn ceiling above our drywall ceiling, and our ceiling drywall only seems to be supported by 2x4s, which are spaced about 2 feet apart. Is this sturdy enough to support a lightweight (< 35lb) ceiling fan, such as this one, using a simply a ceiling fan brace and box, or would something more drastic need to be done here? My question is similar to this question, except that (1) I have no attic access, as it's below our second story, and (2) the 2x4s seem to be more stable than the metal rods the new ceiling drywall was screwed to in that question.

Edit: The 2x4s appear to be around 8 feet or so long, at least. That's the width of the room, and they seem to span the width of the room, if not longer than that. On the other side I don't even seem to see if they are connected to the other side of the room.

A 2x4 that's 2 feet from the one that the plastic ceiling box was attached to

The 2x4 that the plastic ceiling box was attached to, running to the end of the wall, where there appears to be another 2x4 nailed in to something.

Answer 1

I wouldn't do it.

Even a 35-lb. fan needs to be connected to a solid structure, such as the house's framing. Those strips are often used in my area, and are typically not considered part of the house structure. They are likely just strong enough to support the ceiling (a static, distributed load)--not an overhead vibrating point load.

One thought: how about reinforcing the existing 2x4? You could:

1. Remove part of the ceiling;
2. Add a sister beam (or two) to the existing 2x4;
3. Add some Strong-Tie-type brackets to the ends of the 2x4's to better tie them to the existing structure.
4. Replace the ceiling drywall.

Admittedly, a hassle, but a real improvement over what you have.