Chances are this is a non bearing wall.
Non load bearing roof truss.
If there are two plates refer to an engineer.
It can take various forms and often used for aesthetic purposes adding height and focal interest to the ceiling.
An example of a load bearing wall call be seen on the right.
For many multi family projects floor and roof trusses joists span from unit wall to unit wall while interior non load bearing walls tend to fall near the center of the floor span.
For example a gable end truss may be designed with support members that transmit the roof weight load outward to the side walls allowing the end wall directly below it to have breaks or openings in it that would otherwise be impossible.
An example of a non load bearing partition wall can be seen on the left.
To enable the roof truss to deflect under loads nails to the truss must be installed at the top of the slotted holes and not hammered home to allow a loose fit only.
A rolling node is assigned to provide support in only one direction often the y direction of a truss member.
A pitch truss with a sloping or non sloping vertical interior ceiling detail.
If the wall in question is parallel to the joists trusses it will likely not be load bearing.
One top plate and a space between the bottom chord of the truss and the top of the wall non load bearing.
Internal wall brackets are used to connect internal non loadbearing walls to roof trusses at maximum 1800mm centres.
Actually a quick way to determine if the wall is bearing is to cut hole at the top to see if it has one or two top plates.
The formula for truss loads states that the number of truss members plus three must equal the twice the number of nodes.
The remaining third node of each triangle is known as the load bearing node.