Mike Marlow wrote:
Bill wrote:

Another possibility I am willing to consider is using 2 layers of 3/4"
ply (Columbia "Purebond brand hardwood plywood, since it's
Formaldehyde-free--not Baltic Birch). Of course at +$40 a sheet,
that's a pricier alternative. I'll check with with local lumberyards and
see
whether they have started carrying the Purebond products (as LarryJ
keeps reminding me to do!) Maybe 2 layers is overkill for this
application...but maybe not--I know stacking layers of drywall is
"routine".
Do yourself a favor Bill. Cut a piece of 3/4" plywood the size you are
planning to use. Support it off the floor at all four corners in a similar
manner to what the casters will do. Get up on it. Jump up and down. Park
your car on it. Notice any deflection? You're going into major overkill
here.

Stacking layers of drywall is routine? Maybe for very specific
applications, but not generally.

My drywall book made layering drywall sound
pretty typical for commercial applications (IIRC, even going
to 3 layers, on occasion). I guessit depends on how
particular one is about his or her wall.

Say you had a wall that hada lot of wear. It would probably be
faster to put a new 1/4" sheet on topthan to replace the old stuff.
I haven't done it, and there are probably some code issues too.