I want to hang n fan in a covered pavilion which has a gazebo like roof, held up by rafters. I've purchased a ceiling fan box/support that is designed to fit between joists, but there are no joists. I was wondering if I could use 2 stacked 2x4's attached perpendicular to the rafters (with lag bolts) and then connect the fan box between the two by fours.

This photo shows the roof rafters and the drawing indicates the idea. The other photos show a mock-up of what it would look like (ignore the clamp, it is just holding the mock-up together -- in the application the 2x4's would be attached to the rafter with bolts).

Basically, the 2x4's create a 'joist' for the fan box to attach to. (The plates on the end of the fan box are aligned so that they can only be attached on the ends, and not flat against the joists).

Will this work? Or is there another way to do it?

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  • Are you OK with having the fan a bit off-centered in the gazebo? Commented Jun 23, 2020 at 23:44
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    You could easily run a short piece of 2x4 level between two rafters at the peak, and use the saddle box on that. That's what I did for my cathedral ceiling porch, worked beautifully and should work here as well. Commented Jun 24, 2020 at 1:52
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    Your crossbar and box unit are not rated for exterior use. Commented Jun 24, 2020 at 4:05
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    Dude, seriously, one of the best "first posts" I've seen! Well done! Clearly asked. Good details. Nice, focused photos. If we had a Hall of Fame for first posts, this would be a definite entry!
    – FreeMan
    Commented Jun 24, 2020 at 13:50
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    @ThreePhaseEel It's obviously a radially symmetric space. Off-center will look stupid. Laziness is the only reason to do it that way. Ask yourself what you would think if you paid a professional to do it and that's what they did - you'd fire them and never call them back, right? It's a very quick and very easy job, even with limited framing experience, to build out a simple support structure up there to hold the box in the center.
    – J...
    Commented Jun 24, 2020 at 14:08

2 Answers 2


A lot of this comes down to aesthetics and practicality, so you will probably get lots of right answers. Here's my take:

I would run your short piece of 2x4 level at the peak alongside 2 of the rafters. You will then be able to use a saddle fan box to mount your fan. This box slides over the 2x4, and is only fastened using a set screw. You then use wood screws to actually fasten the fan bracket to the 2x4 behind the box, not the box itself.

enter image description here

  • Really helpful, thanks! Looks like a perfect solution.
    – bill333
    Commented Jun 24, 2020 at 2:14
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    Is that type of box legit for outdoor locations...? Commented Jun 24, 2020 at 4:04
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    @JimmyFix-it Some locales would be OK with it if you used armored cable and a clamp. Since it has a knockout on the side, this should work since it's not directly exposed.
    – Machavity
    Commented Jun 24, 2020 at 12:38
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    If you want this to be really centered, continue your thought of using a couple of 2x4s (or 2x6s for additional stiffness) on each side of opposing rafters, then run a 2x4 horizontally between the pairs. This will get the horizontal 2x4 directly centered under your peak and you'll be able to align the saddle box directly under it for as exact an centered mount as you can get.
    – FreeMan
    Commented Jun 24, 2020 at 13:56
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    Conduit = good. Exposed box that is designed to be inside the wall = bad. To do this properly you need an outdoor electrical box. This could be easily accomplished by mitering a 2x4 to span the rafters and surface-mounting a weatherproof box right in the middle under the peak, then running conduit to it. Commented Jun 24, 2020 at 22:39

Return that bracket and get a box only (no metal bar) rated for a fan. Run a length of 2x4 or 2x6 horizontally across from one rafter to the opposite one. Mount the box on the underside of this 2x. It will have no wobble and you can center it. You don't need bolts to attach this horizontal member; 2 to 4 screws on each end would do.

You might need an extended 18" down tube on the fan so the ends of the fan blades don't get too close to the rafters.

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