I am building my garage I put trusses 4' on centers with 2x4 perlins every 2' for the tin roof my friend put up sheet rock and he said will sag with sheet rock since it is on 4' centers, I may have to put tin ceilings, is there any other way. I am going to spray foam ceiling for insulation. thanks Ray my garage is 33x38 with 10' ceilings
