On Apr 28, 9:47*am, dpb wrote:
stryped wrote:

...

I was told by the metal supplier they do it all the time and it does
not sag. The truss manufacturer says drywall is too heavy.

It's done by going perpendicular across the trusses or adding purlins
same way as a wall; your choice. *The rigidity in metal is lengthwise
across the corrugation or ridge; lengthwise it has no resistance to
bending much at all and would be quite limber and difficult to install
w/o support.

I'd suggest go to a manufacturer's web site pick a product and get their
recommendations on installation for the application envisioned (or start
w/ the applications and get recommendation on product(s) _and_
installation actually makes more sense).

--

I would be going perpendicular to the trusses. I actually have small
furring strips between the russes every two feet or so to hold the
insulation in, but not sure if they are spaced right to use as
additional nailers without it fallin gon a rib or something.