"RicodJour" wrote in message
oups.com...
xrongor wrote:
hey all

im hanging 4' x 8' x 5/8" firex type drywall on my garage ceiling and
plan
to pump in 8-10" (max) of loose insulation on top of it.

rafters are 24" apart. am i good with 12" screw spacing to hold this up?
for a 4x8 sheet this basically puts 5 screws across the width, every 2'.
or
25 screws for a whole board.

everything ive read seems to point to 12" spacing, and ive been told it
meets code. i just want to make sure before i pump the stuff in and
watch
my ceiling fall due to the weight.

USG calls for 12" OC screws as maximum spacing. Don't be pennywise.
Go with 8" OC. It'll cost you an extra fifteen minutes of your time
and a few bucks for the screws.

but why is there such a discrepancy? my local inspector told me that 12"
centers is good enough for up to 12" of blown in insulation on top of the
5/8 firex. code normally has some fudge factor built into it... if code
says x is enough, why does everyone seem to suggest using x+1?

have you seen an actual failure when someone used 12" spacing?

i mean you don run 10 gauge wire when 12 will do, just to stop from being
pennywise... you dont make fishing poles out or rebar either...

randy