I'm building a 10 x 14 shed with a 6/12 pitch roof. Do I need collar ties and ceiling joists for each rafter. The rafters will be spaced at 16". I live up north where snow is very common. Thanks

Use collar ties on every rafter and a cross joist every 3 or 4 rafters.

If using ceiling for storage install joist at every rafter and collar tie every other rafter. Collar tie should be set at 1/3 the distance from ridge to floor.

Chuck