Help with ceiling

[MarkDePonzi]

Hi
I want to sheetrock my ceiling . My Joists or 2x6s are about 48 inches apart.

I searched around and many suggest strapping the joist with 1x3 on 16 inch centers.

I am wondering if I should put another 2x6 in-between the 48 inch span to keep the strapping from flexing ? Or use 2x4s instead of 1x3 for strapping ?

I am guessing I maybe using the wrong terminology these may not be joists this garage is framed not with trusses but more like rafters.

Regardless the 2x6s that run on the bottom that I would attached the strapping or furring two are 48 inches apart. I need to frame in some more studs to prevent sagging
Any ideas

 

[mikegt4]

From the photo those appear to be rafter ties, not joists. Rafter ties are for keeping the walls from spreading apart and not designed to take a vertical load such as a drywall ceiling.
With some properly engineered additional structure a ceiling such as you want is possible.