Garage Roof Trusses Sagging

Should the bottom cord of one or more trusses be sagging or damaged it may be reflected in a sagging ceiling or if the roof is over loaded to heavy then the downward pressure may cause the sagging.
Garage roof trusses sagging. If the framing is sound and problems are not found elsewhere but the roof still sags the problem might have originated because of poor installation of the plywood sheathing or shingles. It can be nailed temporarily to each truss as the next truss is put in place. Typically they are lapped and then toe nailed together in its center so that the correct length can be achieved. A sagging roof line may original from the ceiling s horizontal rafters.
As demonstrated by the dent in my pickup s hood vibrations from the garage door opener can cause items to shimmy around and eventually crash down onto your car or you. This repair will keep the trusses from sagging. If you have traditional site built roof framing your storage capacity depends on the design of the framing. Drywall instead of 5 8 in.
If your ceiling drywall is sagging between joists sometimes called pillowing it s probably on the top floor and attached to the roof trusses. Then slowly allow the trusses down. Are doors sticking or jambs out of square. However it is important to fix the rafters before doing any other work to the roof.
Usually trusses are put 24 inches apart. Half inch drywall can sag if it s hung under roof trusses that are spaced every 24 in. When the framing of the roof is put together quite frequently two of the ceiling rafters will be fixed together as this will create a much longer span. Finally make sure stored items are securely locked in place.
The first step is to find out how many rafters are sagging and if anything else is damaged. Even ceiling cracks can be caused by damaged trusses or downward pressures. However a bigger problem is nailing the new web member to the ridge peak of the truss and there will be 2 members nailed in this location. Sagging rafters may be the result of having framed the roof with lumber of dimensions smaller than current building standards such as using 2x4s or 2x6 s or there may be damage to the framing from insects or rot.
If so i bet the installers used 1 2 in. So you should start by inspecting the roof from the under side or attic. One good thing about wood construction is that failures occur slowly and with a crack or split in the wood.