Yes either a ridge board or a ridge beam is necessary and required by the building code where roof rafters meet at the the center of their span.
Ridge board roof trusses.
They are secured at the bottom by ceiling joists.
These horizontally installed boards give the trusses strength and stability.
The ridge board runs the length of the building and provides support for the tops of the rafters helping the whole roof structure work together as a system.
Ridge beam sizing is based on the span of the beam between supports and the amount of roof load supported by the beam.
The ridge board must be the same width as the rafter boards.
King post truss parts explained.
Collar ties placed horizontally halfway down the rafters hold the rafters and roof planes together.
Line the top of the truss with the top of the ridge board and nail the truss rafter to the ridgeboard on each side.
It will probably be a tight fit and take a little hammer work to get each one into place.
This video shows how to make roof rafters with a rafter square and or a speed squ.
It is often used in simple roof trusses such as in the shed porch and garage.
A ridge beam is a structural member used to support the ends of the rafters at the ridge transferring it s loads to posts or gable end walls.
A non structural member of the truss where rafters can lean against and connect to.
Rafters are made from sloped framing boards of dimensional lumber usually 2x8s or 2x10s connecting the roof peak called the ridge board to the plates of the exterior walls.
The ridge board and rafters are the strength of the roof.
The ridge board must be set as perfectly as possible so take your time and use careful measurements.
This video covers one of the most exciting parts of roof framing installing rafters.
Also called minor rafter because it is smaller than the principal rafter major rafter.
In heavy duty construction a ridge beam might be used instead.
Raise the trusses one at a time and work the ridge board into the gap.
We will go over raft.
This board forms the bottom member of each rafter and of course the ceiling of the space below.
Ridge beams are required by code if the roof slope is less than 3 in 12 irc section r802 3.