Sagging floor joists
I have a house in RI built in 1956 that seems to have been built like a tank in most respects, but lately it seems that the floor has sagged in one quarter of the house. The only changes that have occurred have been a rather heavy bunk bed put in and, more recently, two large skylights. It is a ranch. I'm wondering if this could be perceptual but my whole family seems to notice it. There are no cracks in walls, though one small one in the ceiling is newish. Under the house (the basement is a 4 foot crawlspace) there is a noticeable sag over a span of about 20-30 feet.
Could changes to the roof when the skylights went in have any effect?
Is an LDL beam of some sort a simple solution?
Thanks. I can post photos if that helps if I can figure it out.