Special boxes designed for use with ceiling fans are sturdier than standard boxes and will typically have a support bar or attach directly to a joist.
While you're at it, make sure that the box is securely fastened to the overhead joist or beam.
The instructions on your deck plans will tell you exactly how far to place your joist apart.
Always secure the brackets into a structural element like a stud or joist.
Make sure you are anchoring your tracks to a stud or ceiling joist.
Apart and supported by a cross-channel joist at each springing.
Joist was formerly deemed a remarkable achievement, though now there are several works producing 24-in.