[DangeloInspections]

The trusses are 24" o.c. , running perpendicular from your Lanai sliding glass doors on most designer homes.
Dependent on what type of stud finder you have it should work.

I often find at least one small crack running between the sheets of ceiling drywall in the Lanai.....if you have a crack that will show you a truss.

Often knocking on the ceiling you can hear the difference in the sound when you hit a truss...it will sound less hollow.

Hope this helps. Frank