The main/loft floors are ¾" × 3¼" T&G pre-finished
oak I bought from a flooring guy in Medford for $3.35/ft², a good deal.
The brand name I didn't know but quality is very good, as he claimed. I
also bought a flooring nailer from Harbour Freight, who usually sell only
the cheapest of crap, but the flooring guy said that is what his crews use
and like and at $140 it works just as well as the $400-500 name-brand ones.
I'm starting with the loft since I need to penetrate the loft floor with
the demand heater vent pipe. Underlayment is 15# felt (rosin paper, such as
my flooring book says to use, is unknown out here). I'm laying out the
first eight rows loose on the floor to pick the pieces for color and grain,
and make sure the joints are staggered.