I am converting a 18x22 garage into living space. Is there any way to retro fit a ridge beam under the current rafters so the joist can be removed to vault the ceiling. The rafters are 2x6 (2x8 ridge board)on 16 centers and the roof's pitch is 4/12. I would like to avoid collar ties if possible. I live in northen Ohio so snow is a concern. I will contact an engineer but would like so insight before hand.
General answer, but yes, it can be done in most cases. Essentially, the engineer will probably have you add a beam of some sort under the existing ridge. With conventional framing and ceiling joists, the ceiling joists keep the ridge from moving down and allowing the walls to thrust outward. With your potential setup, the ridge is sized as a beam, and is sized so it cannot move downward and allow the rafters and walls to thrust.
The challenge is getting the beam up there and getting solid bearing under the ends.
You're definately smart to contact an engineer for some design help.