Helping a friend at the weekend, and found a roof leak has caused the wallplate to disintegrate, which I removed with the vacuum cleaner ;-)
Originally sitting on this was a sodding great compound beam which runs the length of the house and has a loft extension built on it. It was floating in mid air with the wall plate having gone from under it, and has dropped about an inch from where it originally was. I have for the time being packed the gap under it with engineering bricks so it can't drop any further, although before that I got friend to go and walk around and then jump in the loft extention, and there was virtually no movement in the beam-end (much less than 1mm).
So the question is, is it worth trying to jack the beam back up by the inch it's dropped before reinstating the support under it? The two doors in the loft extention both jam slightly in the frame, possibly due to this distortion. I'm guessing the weight might have transferred to some other part of the structure which might not be so well suited to take it, although there's nothing else under that beam for a few metres at least.