If your roof is made with trusses you will need a special shutter that allows the truss to run right through the middle of the opening. That is because you should never cut a truss because it is engineered to be strong only when it is complete with all of its members. There is one panel in the middle of the shutter that does not open and covers the truss. Another option would be to use a regular shutter but lower the ceiling in the area of the fan by about 6 inches so the regular shutter would have room to open entirely below the truss.

If your roof is made with conventional rafters and joists, you just need the regular premium shutter.