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George E. Cawthon George E. Cawthon is offline
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Default plywood, weight capacity

Rich wrote:
George E. Cawthon wrote:
Don Young wrote:
"AKA gray asphalt" wrote in message
news How can I figure the amount of weight a piece of plywood, probably
3/4 or 1" ... how much weight it would hold? It would be 24" x 60"
and supported on both 24" sides and one of the 60" sides? The
weight would be evenly distributed but there wouldn't be any
support in the center except along that one side. I could use
butcher board or block, whatever it is. Thanks ...


Over time it will sag noticeably of its own weight. You need more
support for a shelf or platform that size.

Don Young


You must be using plywood made from cardboard.
3/4" plywood on 24" studs (essentially what the op
is doing) is never going to sag by itself.

The Sagulator, shows that a 1400 pounds would
result in a deflection of 0.1 inch. a sag of 0.1"
wouldn't be a problem even if visual was important.


I don't think your reading the OP's specs. It is 24X60 shelf supported on
both ends and along one of the 60" sides leaving one of the 60" sides
unsupported it will deflect and sag under it's own weight with that
configuration over time. Time to recalculate with the "sagulator".

Rich



Sorry, I apparently read it wrong, thinking it was
supported along the two long sides. Don't think
the sagulator will help. It won't sag along the
24" sides or the one 60" side. 24 inches wide is
pretty wide, so with enough weight it will sag.
It will not sag on it's own from my experience.

I have 10" wide shelves 30" long supported only on
the end and they don't sag with a full load of
large books. I also have a bookcase with 9" wide
shelves 48" long and supported with nails through
1/4" plywood on the back edge and these shelves
don't sag with a full load of magazines. Each
shelf supports 140 pounds (I weighed a 6" section
of magazines).


The only way to tell how much the ?shelf? will sag
is to support a 2 x 5 shelf on 2x4's (on the
floor) and step on the shelf along the unsupported
edge and in the middles of the long length (and on
other parts of the shelf). That will give a
decent idea of what the shelf will support. I
suspect that the shelf will support at least 300
pounds distributed evenly over the shelf with
little sagging.