Can anyone tell me which of two plywood sheet configurations would be
the stiffest, or do they have the same stiffness?
Any other observations about the stiffest configuration of plywood
sheets under 5/8" thickness?
A bottom layer of sheets of 1/4" plywood plus a top layer of 1/4"
plywood sheets overlaid in the centre of the lower layer's joints and
glued to the lower layer.
A single layer of 1/2" plywood with the same outside dimensions as
Thanks in advance for your helpful replies.
In configuration 1 you mention joints.Are you laying out a series of sheets
and then staggering the second layer? Done properly, that would have
marginally more stiffness at the joints. Lots more labor and no assurance
the glue joint is as good as the factory ply. I'd go with the single
The local lumber yards here, sell 1/2" CDX with 3,4, & 5 ply. Five ply
will be your stiffest (and most expensive out of the 3 choices) plywood, the
plys are alternated when glued/compressed together.
IMHO, stay away from 3 ply for any application except when hung vertically
for exterior walls.
Being _normal_ building grade sheets are 4'x8', it sure does make a
difference how it is installed.
Guess if you've never used the better grade of 4 ply compared to 3 ply, you
wouldn't see any difference.
All else being equal a single sheet composed of the same total number of
layers as two sheets half as thick and having half the total layers as the
single will be stiffer. However that difference is not likely as the total
number of layers will not likely be equal and you need to consider the
overlap of joints that will add overall application stiffness. In addition
there are many other factors relating to stiffness.
Iff stiffness is the only consideration and water resistance is not a
factor, then wafer board offers greater stiffness than plywood, not overall
strength, just stiffness.
Remove the obvious to reply. Experienced and reliable
Concrete Finishing and Synthetic Stucco application in the GTA.
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