[VAC] Re: More frame off stuff

["Dr. Gerald N. Johnson, electrical engineer" <geraldj@xxxxxxxx>]

CCA is a copper and arsenic compound used to rot proof green colored
outdoor lumber. The standard retention is 0.40% and the standard lumber
used for decks is delivered wet from the treatment. It shrinks
excessively for any nice use. Foundation grade has 0.60% retention, is
kiln dried after treatment so it doesn't shrink nearly so violently, and
is guaranteed for 40 years in the ground. Foundation grade plywood comes
in nominal 5/8 and 3/4 thicknesses, probably 1/32" shy like most
plywoods (other than marine). And there are 2x6, 2x8, 2x10 and 2x12
available in foundation grade for use in making wooden foundations walls
and for use as footer plates. As far as I know the only grade is CD so
its not ready for a finish floor. Might need an overlay to make a smooth
surface for vinyl sheet goods or tile. Part of the weight is the
treatment, part is the use of strong wood like long leaf southern yellow
pine that is heavy without treatment.

Besides the treated wood, wooden foundations depend a great deal on very
careful drainage to minimize the water pressure from the soil.

Gerald J.