We are building a 16'x28' workshop. We intend to put a gambrel roof on it to allow for maxium height inside. there will not be any joists going across the middle. I am not sure if I am using the right term for that. What I am trying to say is the building will be open from floor to roof. I have been looking at the gambrel roofs at the HD display sheds and I would like to know where to purchase those metal ties they have holding the trusses together? I see ones that look like them in the store but they all say not for trusses.
Also the HD sheds have a 2x12 going across the middle of the shed for structural support. If I instead put a 2x12 5' in from the front and 5' from the back leaving approximately 18' of open space in the middle will that sufficient structural support?