What Was Behind the Ceiling (and Why It Failed)
Ceiling fans are heavy. Most of them are between 15 and 50 pounds, and when they spin out of balance they pull on the mounting point with way more force than the static weight suggests. Electrical code (NEC 314.27) requires fans to be mounted to a UL-rated fan box that's either screwed directly into a joist or supported by an expandable metal brace designed for the load.
The previous owner had used a regular plastic electrical box (the kind designed for light fixtures, not fans) screwed into a piece of construction scrap. That scrap was already split when I pulled it out, and the screws had been working their way loose for years. Once the wood gave up, the fan came down. I should have inspected it when we moved in. I did not.
The good news is that this kind of repair is one I had done before, just not under a hanging electrical fixture in my own bedroom. The basic steps are the same as any medium-sized ceiling patch, with the added complication of installing a proper fan brace through the hole before you close it up.
What I Bought and What It Cost
Total spend for this repair was $63.40. Most of it I already owned. Here's the breakdown of what I had to buy:
Saf-T-Brace expandable fan brace (Home Depot, $24.97). This is a metal bar with adjustable ends that you push up through the ceiling hole and tighten until the spikes bite into the joists on either side. It's rated for 70 pounds for fans and 150 pounds for fixtures. Critically, it does not require attic access to install, which is good because my attic access is in the closet at the far end of the house.
I picked Saf-T-Brace because the reviews on the Westinghouse equivalent had too many complaints about the spikes not seating properly. Both are sold at most home stores. For more on choosing fan supports, the Family Handyman guide to fan brace installation walks through the differences.
Fan-rated metal pancake box (Home Depot, $6.43). This replaces the plastic box that pulled out. It mounts directly to the new brace and is the actual support point for the fan.
Drywall patch kit with 6x6 metal mesh and joint compound (Lowes, $14.00). I actually had compound at home, but the kit included the metal mesh patch I needed and was cheaper than buying mesh separately.
Replacement ceiling fan (already owned). The old one had bent blades from the fall, so I used a spare we had in the basement from our last living room project.
Miscellaneous (in tape, primer, paint touch-up): $18 worth from existing supplies.
The Repair, Step by Step
I did this over two days, mostly waiting on compound to dry. Active work was maybe four hours total.
First, I cleaned up the existing hole. The drywall was torn rather than cut, so I used a utility knife to trim the ragged edges back to a clean shape. I ended up with roughly a 5-inch round hole. I didn't enlarge it any more than I had to because the metal mesh patch was rated for openings up to 6 inches.
Next, the fan brace. The Saf-T-Brace goes in through the hole, you rotate it until both ends contact the joists, and then you keep rotating to expand the bar. The spikes on the ends dig into the joists as you tighten. I'll admit I was nervous about this part because you can't see whether the spikes are seating well, but I tugged hard on the brace once it was tight and it didn't budge. The instructions said to expect that.
Then I attached the new pancake box to the bracket on the brace, fed the wiring through, and confirmed everything looked right before patching.
For the drywall patch itself, I used the self-adhesive metal mesh approach instead of cutting a backer board. The mesh stuck over the hole, two thin coats of compound covered the mesh, and a third feathered coat blended it into the surrounding ceiling. I sanded between coats with 150-grit, then 220 before priming.
What I Got Wrong
Two mistakes worth mentioning.
First, I put the first compound coat on too thick. I was so focused on hiding the mesh that I loaded up about a quarter inch of mud in one pass. It cracked while drying. I had to scrape it back and start over with a much thinner coat. Hot mud (setting compound) would have been fine to apply that thick, but I was using regular premixed all-purpose, which shrinks more and cracks if you go too heavy. The USG technical documentation on joint compound is clear that premixed compounds work best in thin layers.
Second, I didn't account for the fact that the ceiling had a knockdown texture. Once the patch was smooth and primed, it looked like a perfect circle of polished drywall surrounded by texture. I had to mix up a thin coat of compound, dab it on with a brush, then knock it down with a putty knife after it set up for a few minutes. It took two tries before the texture matched well enough that you have to be looking for it to find the patch.
Should You Just Hire Someone?
If you're not comfortable working with electrical wiring, yes. The patch itself is straightforward. The fan brace installation is also pretty foolproof. But cutting the power at the right breaker, identifying the wires correctly, and reconnecting the fan are not steps to wing if you've never done them.
The local quote I got from a handyman was $280 to install the brace and patch the hole, not including the fan itself. That's reasonable for the work involved. For me the math worked out because I was comfortable with everything except the patching, which I wanted practice with anyway.
One thing I'd push back on: don't let a handyman put up a new fan without using a proper fan brace. The original installation in my house was exactly this, and it took 17 years to fail. Pay the extra $25 for the brace. It's not optional. The Consumer Product Safety Commission has documented dozens of incidents involving falling ceiling fans, and almost all of them trace back to inadequate mounting.