There have been cracking/snapping sounds coming from my ceiling. I can't see disturbance with the cornices. However, when I go up into my roof, I found that these hitches (which perpendicularly connnect the bottom cord of the roof trusses to the top cord of the internal walls [non-load bearing]) have their nails all the way down the bottom of the slot. I read that they are meant to freely move vertically, and at the time of construction the nails are near the top of the slots, indicating there is meant to be some space between the roof trusses and the internal walls (which now has been reduced.)
This is a two storey house. Below these internal walls, on the ground floor, it is an open space. A carpenter told me it should be ok becase there should be a metal beam between the ground and second floor. HOwever, I do not remember there being a metal beam at the time of construction, just the timber I-beams. Additionally, the floor has dipped/sagged at the door way of these internal walls on the second floor, and whenever I walk near them there is the cracking/snapping sounds, especially first thing in the morning.
I think that the roof is sagging onto the internal walls and pushing the floor down. What do you think? And if so, can you point me to where I can find out how to rectify the situation as non-invasively as possible?