Is it rafters you have, or trusses?
Good point. They are 2 x 4 trusses that span a very wide area so even if I stiffen them with another board the load in the middle really stresses them. I could move towards a side where the leverage of the weight would not be so bad but then I would not be able to work around it.
I have had problems in the past when there is heavy snow on the roof the trusses sag down low enough to keep the overhead door from opening - they block it from traveling back under the trusses on the tracks. I have to shore up the trusses when that happens also. It is not the best built pole barn in the world. The PO built it and he was not what you would accuse of being a skilled builder.
I did pick up the lumber but failed to get the engine pulled this weekend due to issues with my CUT not starting and I had to work on Monday. The CUT starting problem is in the stupid safety switches and I got it running by totally bypassing them. I think I will install a separate starter button and be done with the safety junk. It did start again later without by-passing the safety circuit so the problem is intermittent and would be a real pain to hunt down. I don't have time to piddle with it, I just want a tractor that will start reliably when I need it to.