I figured if I get the chance, I may do something to reinforce it. I didn't know if by adding a strap, I would weaken the bottom part of the board doing all the work. I guess I shouldn't nail within two feet of the hole? or something like that.
Its amazing that the original owner went to the trouble to make sure that all vertical duct runs are on interior walls, yet let the installer cut a large hole in a joist.
Now, that I have a sofa on that side of the living room, it has become a small concern. We use the family room and game room most of time and the living room sees little use. I thought I might do something with it before having any large groups over that might congregate there and apply stress to this joist.
Let me know what type of strap I might use?
I also like the idea of a support beam. Would I put a support beam right up against the joist directly below the hole, or make a U bracket to support the joist on either side of the hole?