"Paul A" wrote in message
news:viXse.13787$Nx1.11750@trndny05...
I need to install a new header to enlarge a window (in a load bearing
wall).

I was always under the impressing that kiln dried lumber, instead of green
lumber.
was the only way to go when altering existing construction, to avoid the
problems
of shrinkage.

As far as I can discover, only green lumber is available in New Jersey for
anything
larger than 2 x 4's.

I am particularly concerned that the ceiling, which is supported by this
header,
will crack over time, as the new header shrinks.

Am I worrying about this unnecessarily, or is there a technique of
installation
that avoids the problems of shrinkage?

Window header stock (beams) doesn't come kiln dried. At least I've never
seen it come that way. Your option is to use 2x (insert width here) kiln
dried stock and nail them together using 1/2" plywood in between to fill the
width. Or buy the thick stock beam you need which is what I would do if I
was framing it.
SH - The "general contracting" woodworker