Create A Ceiling Vault In Existing Rafter Roof
Is it possible to retrofit a standard rafter/joist style roof to a scissors truss configuration without replacing the existing construction?
It sounds like what you are proposing is not necessarily to make a scissors truss from conventional framing but to vault the ceiling joists. This is certainly an option but we recommend consulting a structural engineer for this project.
An alternative is to use scissors trusses, which would replace the existing roof framing.