In article Zs_le.7390$tv3.1003@trnddc06, wrote:

Edwin Pawlowski wrote:
"Joseph Meehan" wrote in message

Well few builders will put a beam in larger than necessary to carry the
weight of the structure. You need to know what it is already supporting.


Once you determine that, I'd still put in a vertical support under the beam
while I was doing the lifting.



And I would make the vertical support have a very large base
in order to NOT crack my concrete floor with a point load.

Say you use a 4x4 as the support. Isn't there a max base size that's going
to do any good? If it was 3/4 plywood, at some size of the plywood and
load, woulnd't the ply "buckle" upwards and reduce the area that is
transfering the load to the concrete?

--
charles