Bypass Sliding Barn Door Track CCJH U-ShapeStability L Shaped Bracket L Shaped Bracket make the bypass system run more stability. Q&A Q: How much space do I need above the doorway? A: 6" clearance is needed from the top of the door to the ceiling (or crown molding) for CCJH sliding barn door hardware kit to fit accurately. Q: Can I cut the rails? A: Of course, you can cut it by yourself. But we have 3 20ft rails for your choice in fact. You can choose any size you need. Q: What is the