Old work fan box

[mkgrady]

I need to install old work fan boxes in an existing metal strapped ceiling covered with sheet rock. This would be easy if the frame were wood. I would use the box with the bar that gets rotated and it jams into the wood joists. What do I use when the ceiling is strapped with metall channels every 24"? The metal channel is that stuff shaped like a "v" with a flat bottom instead of a pointed bottom. I hope that makes sense.

 

[Ponchik]

IMO, it will be better and safer to open the sheetrock and construct a support system that is somehow attached to the structural ceiling. i would use 2x4 or 2x6.

Even with 2x4 lumber 24" spacing i don't feel comfortable using the retrofit ceiling fan boxes. They claim it is designed for 24" spacing but it feels very flimsy.

 

[hurk27]

U use Arlington saddle and side saddle boxes for retro-fit and even new construction, but with metal strips I'm not sure depending upon how stiff they are.

Here's there web site, there is a lot of different types so maybe one will help.

Arlington

Or here is a direct link to their "Fan and Fixture Box's"

 

[masterinbama]

What are the metal firring channels attached to?

 

[kwired]

IMO, it will be better and safer to open the sheetrock and construct a support system that is somehow attached to the structural ceiling. i would use 2x4 or 2x6.

Even with 2x4 lumber 24" spacing i don't feel comfortable using the retrofit ceiling fan boxes. They claim it is designed for 24" spacing but it feels very flimsy.

It may feel flimsy but the fan pulls downward and does not reciprocate. I weigh near 300 pounds and if I can hang my weight from that brace I sure hope it can support a fan that likely only weighs between 10 and 50 pounds, and the brace likely has at least a 70 pound rating.

You ever climb around on framing members and realize only a single 16D nail is supporting your weight or a temp brace that supports your weight? They are stronger than one realizes. I also trust them more than screws. If a single screw - especially the ones used for framing type purposes, is all that is holding me up I am more conscious of that fact. If those screws fail it is because they are harder metal and just break off, the nail on the other hand just bends and still holds on longer than the screw will.

 

[mkgrady]

What are the metal firring channels attached to?

They are screwed to metal bar joists. Not sure of the distance between bar joists.

I wonder if I could slide a piece of unistrut in a round hole and lay it on top of the metal firring, then put a round fan box that has old work ears, then screw the back of the box to the unistrut using a spring nut. It probably should be 2 unistrut spring nuts. I don't know, I just wish someone made a product for this application.

 

[kbsparky]

Strut supported by bar joists should do the trick. I would not want to attempt to support dynamic weight of a fan with "hat channel" -- that stuff can be flimsy.