"JayB" wrote in message
...
I am insulating and finishing an attic space. The sloping roof rafters are
24 inches on center. Between the rafters, I will be placing rafter vents
and insulation, and then sheetrock over that.

My question is about the thickness of sheetrock that I need to use. I
think that 1/2-inch sheetrock is probably too thin for rafters that are 24
inches on center and would tend to sag.

One option is to use 5/8-inch sheetrock.

Another option is to double-rock it with two layers of 1/2-inch sheetrock.

Any suggestions as to what would be the best way to go with this? --
5/8-inch, double 1/2-inch, something else?

1/2 inch will work on 24" centers. If the insulation is heavy you can go to
high strength.
http://www.nationalgypsum.com/submit...29%2000-06.pdf

Be sure to put the sheetrock perpendicular to the rafters. The place
next door to me, which I bought a few years ago, has a 16x20 den that
was added, and the ceiling was installed parallel to the 24" oc
rafters-- it looked like a washboard. It had been vacant for a while and
the roof leaked so a lot of the ceiling was laying on the floor by the
time the deal was closed. I ripped the rest out, added 2x4's between the
rafters, so I actually had 12"oc, reinsulated and put the sheetrock the
other way. For an amateur, I think it came out pretty well-- looks 100X
better than it did. BTW, both old and new SR were 1/2". Larry

Lp1331 1p1331 wrote:
Be sure to put the sheetrock perpendicular to the rafters. The place
next door to me, which I bought a few years ago, has a 16x20 den that
was added, and the ceiling was installed parallel to the 24" oc
rafters-- it looked like a washboard. It had been vacant for a while
and the roof leaked so a lot of the ceiling was laying on the floor
by the time the deal was closed. I ripped the rest out, added 2x4's
between the rafters, so I actually had 12"oc, reinsulated and put the
sheetrock the other way. For an amateur, I think it came out pretty
well-- looks 100X better than it did. BTW, both old and new SR were
1/2". Larry

Yep, there is a grain with sheetrock, and it is longitudinal with the "long"
axis as your observations bear out.

Jon

"Pat" wrote in message
nvilleaccesscompany...

"JayB" wrote in message
...
I am insulating and finishing an attic space. The sloping roof rafters
are 24 inches on center. Between the rafters, I will be placing rafter
vents and insulation, and then sheetrock over that.

My question is about the thickness of sheetrock that I need to use. I
think that 1/2-inch sheetrock is probably too thin for rafters that are
24 inches on center and would tend to sag.

One option is to use 5/8-inch sheetrock.

Another option is to double-rock it with two layers of 1/2-inch
sheetrock.

Any suggestions as to what would be the best way to go with this? --
5/8-inch, double 1/2-inch, something else?

1/2 inch will work on 24" centers. If the insulation is heavy you can go
to high strength.
http://www.nationalgypsum.com/submit...29%2000-06.pdf


Horse Hockey....Go buy a couple of bundles of Fur Strapping and run it 16
OC..It isn't that expensive and will make a world of difference in the ease
of installation of the drywall and the look of the final product.....If you
don't you will forever be dealing with popped screws and cracked butts..As a
pro I will NOT do a ceiling with no strapping as I can't guarantee it
because it WILL have problems and look wavey......HTH....