the air space for a radiant barrier...which is what foil bubble foil wrap is..is a minimum of 3/4"
air space. using 3" wide bands of bubble wrap doesn't achieve this minimum space.
that said..foil bubble foil doesn't provide much insulating value, contrary to what
sales hype tells you.
here is a comprehensive article about this product:
http://www.energyvanguard.com/blog-b...diant-Barriers
spray foam doesn't do a good job of sealing duct leakage.
I know the foam company will disagree, but I have tested for duct
leakage on foam insulated ductwork..and it does not seal as they believe.
as it goes on quickly & expands, it does not get into the small gaps like
using a paint brush to apply mastic does.
it isn't an approved ACCA duct insulating/sealing product.
if you've ever used great stuff in a can, and gone back a couple of months
later, you'll see that foam shrinks.
you'd be much better off to mastic seal and use duct wrap. foil faced scrim kraft paper
with R-8 insulation properly installed, stapled & taped with fsk tape.
there really aren't shortcuts that work for long, or we would be using them.
routing the water from under the house & installing a vapor barrier on the
ground is the solution for the standing water under the house.
again..no shortcuts to do it properly.
best of luck.
The cure of the part should not be attempted without the cure of the whole. ~Plato