I recently took down a light fixture in the guest room with the intent of installing a ceiling fan. My home is a 90+ year old rowhouse and does not have an attic, so I can't view from below. What I am seeing is the metal j-box attached directly to one of the main roof joists. It appears to have two bolts and one screw attaching j-box to joist. My question, is this enough to support a fan? The box seems very solid, no movement at all, but all the attachment points are on one side of the box.
I will try to attach pictures later, they don't seem to be working now.