For pricing and availability.
Rafter ties for lean to roof.
You can possibly remove them altogether of you include posts in the gable walls to support a structural ridge.
From a practical perspective it s difficult to use high rafter ties on a low pitched roof because the force in each tie increases with the inverse of the pitch.
Simpson strong tie 5 2 7 in 18 gauge triple zinc steel rafter tie.
A lean to roof also called a shed roof slopes in one direction with rafters that rest against another structure at their high end and overhang support posts or an exterior wall at their low end.
Simpson strong tie 6 in 18 gauge triple zinc steel rafter tie.
For pricing and availability.
Rafter ties or ceiling joists acting as rafter ties are required by code unless the house is designed so that the walls or a structural ridge beam carries the full load of the roof.
Lean to rafters then connect to a ledger board against a wall of another shed or house.
You can use common rafters on any shed roof but they make the most sense when constructing a gable roof or lean to type shed roof where they can sit on or attach to top plates of a wall.