We bought a 3 year old house in Illinios with a crawl space. The floor at one end of the house(kitchen)sags toward the middle of the room. I don't see any cracks in the foundation but when I checked the level of the floor joists, it shows that the Mainbeam is too low. I think I could level this myself but I'm worried as to what other problems I could cause if I don't go about the job properly. I would appreciate any help. Also the floor is somewhat bouncy. Is there a way to reinforce the 'I' joists. Thanks, Jim.