I have started to work on our 44 yr old bungalow purchased in the fall last year. The first thing to do is remove the 12" x 12" paper board tiles from the ceiling and then the strapping that was used to staple them to. The straps are 2" x 2" and spiked in four places to the floor joists above. I have started removing the 2" x 2" and I thought I should double check that they weren't also there to maintain spacing between the floor joists. In other words, they aren't structural. I'll post pics.