Before Installing Ridge Vent
This looks like someone has removed the roof
ridge vent and is going to replace it or do some repair work.
I have never been able to install a continuous ridge vent in the areas
where I work, because you need the roof ridge for some of your
structural nailing.
The roof ridge is part of the diaphragm nailing and helps hold the house
together in case there is an earthquake.
I worked on a job one time where the building inspector told us that the
roof would need a continuous ridge vent, and the structural engineer
told us we were not allowed to damage the diaphragm nailing. At all...
The structural engineer of coarse takes precedence over any building
inspector and in a case like mine he was the winner. No ridge vents were
installed on that job, however the city did require more dormer vents
that I have ever seen on one house before.
The city normally wins in the long run.