Call the lumber yard and ask if your market is dry or green. If dry start
with about 19 % or a little less. If green you may want to start with a
little more although we would specify that the building should not be warped
until it has dried to 19% or less. Keep in mind that the framing will dry
as it is being erected and before the finishes are on or plumbing in.
Framing in Iowa will dry out to about 6% winter and 9% in summer. 3/8" per
floor is typical.
George Richards, P. E.