The ceiling in my attached garage is dipping at a seam in the sheetrock. It started gradually, and now is dipping probably 1.5"-2". I suspect the 2"x10"x20' joist is cracked. Is there anyway to brace this with a new joist? A contractor said he would have to take down all the garage door bracing, springs and motor, do the work in the attic, then put the garage door stuff back after the repairs are done. I'm looking for a "Plan B." He wants about $2,500 to do replace the joist. Anyone have any suggestions?