I am in the process of putting a large addition on a 1940's bungalow to make at a 3b/2ba ranch. We are adding new pergo flooring throughout but I have one problem. Where the addition meets the old house there is a 10' threshold. Due to the house being 75 years old, some of the joists have sagged on the older side of the house. The ledger, which is sitting on a sill plate has remained level, but 3-4 joists in have sagged a little. I have had it inspected and there is no structural issue, just age. The drop off is about an inch over 4', after that the floor levels out. My GC has just recommended putting a T strip molding at the threshold and said I should be fine. Is there something else I can do? Should I add some leveling compound to make that drop more gradual?